diff --git a/.gitignore b/.gitignore
index 19015866..d80305ef 100644
--- a/.gitignore
+++ b/.gitignore
@@ -56,6 +56,7 @@ env3
 .env*
 .env*.local
 .venv*
+*venv*
 env*/
 venv*/
 ENV/
@@ -66,6 +67,7 @@ venv.bak/
 config.yaml
 bun.lockb
 
+
 # Jupyter Notebook
 .ipynb_checkpoints
 
@@ -76,4 +78,4 @@ bun.lockb
 llmstudio/llm_engine/logs/execution_logs.jsonl
 *.db
 .prettierignore
-db
\ No newline at end of file
+db
diff --git a/Makefile b/Makefile
index 5a43a3e6..6c957607 100644
--- a/Makefile
+++ b/Makefile
@@ -1,2 +1,5 @@
 format:
 	pre-commit run --all-files
+
+unit-tests:
+	pytest libs/core/tests/unit_tests
diff --git a/libs/core/llmstudio_core/providers/azure.py b/libs/core/llmstudio_core/providers/azure.py
index 2dbd7307..f558f9d6 100644
--- a/libs/core/llmstudio_core/providers/azure.py
+++ b/libs/core/llmstudio_core/providers/azure.py
@@ -62,7 +62,25 @@ async def agenerate_client(self, request: ChatRequest) -> Any:
         return self.generate_client(request=request)
 
     def generate_client(self, request: ChatRequest) -> Any:
-        """Generate an AzureOpenAI client"""
+        """
+        Generates an AzureOpenAI client for processing a chat request.
+
+        This method prepares and configures the arguments required to create a client
+        request to AzureOpenAI's chat completions API. It determines model-specific
+        configurations (e.g., whether tools or functions are enabled) and combines
+        these with the base arguments for the API call.
+
+        Args:
+            request (ChatRequest): The chat request object containing the model,
+                                parameters, and other necessary details.
+
+        Returns:
+            Any: The result of the chat completions API call.
+
+        Raises:
+            ProviderError: If there is an issue with the API connection or an error
+                        returned from the API.
+        """
 
         self.is_llama = "llama" in request.model.lower()
         self.is_openai = "gpt" in request.model.lower()
@@ -72,7 +90,6 @@ def generate_client(self, request: ChatRequest) -> Any:
         try:
             messages = self.prepare_messages(request)
 
-            # Prepare the optional tool-related arguments
             tool_args = {}
             if not self.is_llama and self.has_tools and self.is_openai:
                 tool_args = {
@@ -80,7 +97,6 @@ def generate_client(self, request: ChatRequest) -> Any:
                     "tool_choice": "auto" if request.parameters.get("tools") else None,
                 }
 
-            # Prepare the optional function-related arguments
             function_args = {}
             if not self.is_llama and self.has_functions and self.is_openai:
                 function_args = {
@@ -90,14 +106,12 @@ def generate_client(self, request: ChatRequest) -> Any:
                     else None,
                 }
 
-            # Prepare the base arguments
             base_args = {
                 "model": request.model,
                 "messages": messages,
                 "stream": True,
             }
 
-            # Combine all arguments
             combined_args = {
                 **base_args,
                 **tool_args,
@@ -116,13 +130,13 @@ def prepare_messages(self, request: ChatRequest):
         if self.is_llama and (self.has_tools or self.has_functions):
             user_message = self.convert_to_openai_format(request.chat_input)
             content = "<|begin_of_text|>"
-            content = self.add_system_message(
+            content = self.build_llama_system_message(
                 user_message,
                 content,
                 request.parameters.get("tools"),
                 request.parameters.get("functions"),
             )
-            content = self.add_conversation(user_message, content)
+            content = self.build_llama_conversation(user_message, content)
             return [{"role": "user", "content": content}]
         else:
             return (
@@ -139,6 +153,20 @@ async def aparse_response(
             yield chunk
 
     def parse_response(self, response: AsyncGenerator, **kwargs) -> Any:
+        """
+        Processes a generator response and yields processed chunks.
+
+        If `is_llama` is True and tools or functions are enabled, it processes the response
+        using `handle_tool_response`. Otherwise, it processes each chunk and yields only those
+        containing "choices".
+
+        Args:
+            response (Generator): The response generator to process.
+            **kwargs: Additional arguments for tool handling.
+
+        Yields:
+            Any: Processed response chunks.
+        """
         if self.is_llama and (self.has_tools or self.has_functions):
             for chunk in self.handle_tool_response(response, **kwargs):
                 if chunk:
@@ -388,9 +416,25 @@ def convert_to_openai_format(self, message: Union[str, list]) -> list:
             return [{"role": "user", "content": message}]
         return message
 
-    def add_system_message(
+    def build_llama_system_message(
         self, openai_message: list, llama_message: str, tools: list, functions: list
     ) -> str:
+        """
+        Builds a complete system message for Llama based on OpenAI's message, tools, and functions.
+
+        If a system message is present in the OpenAI message, it is included in the result.
+        Otherwise, a default system message is used. Additional tool and function instructions
+        are appended if provided.
+
+        Args:
+            openai_message (list): List of OpenAI messages.
+            llama_message (str): The message to prepend to the system message.
+            tools (list): List of tools to include in the system message.
+            functions (list): List of functions to include in the system message.
+
+        Returns:
+            str: The formatted system message combined with Llama message.
+        """
         system_message = ""
         system_message_found = False
         for message in openai_message:
@@ -407,15 +451,31 @@ def add_system_message(
       """
 
         if tools:
-            system_message = system_message + self.add_tool_instructions(tools)
+            system_message = system_message + self.build_tool_instructions(tools)
 
         if functions:
-            system_message = system_message + self.add_function_instructions(functions)
+            system_message = system_message + self.build_function_instructions(
+                functions
+            )
 
         end_tag = "\n<|eot_id|>"
         return llama_message + system_message + end_tag
 
-    def add_tool_instructions(self, tools: list) -> str:
+    def build_tool_instructions(self, tools: list) -> str:
+        """
+        Builds a detailed instructional prompt for tools available to the assistant.
+
+        This function generates a message describing the available tools, focusing on tools
+        of type "function." It explains to the LLM how to use each tool and provides an example of the
+        correct response format for function calls.
+
+        Args:
+            tools (list): A list of tool dictionaries, where each dictionary contains tool
+            details such as type, function name, description, and parameters.
+
+        Returns:
+            str: A formatted string detailing the tool instructions and usage examples.
+        """
         tool_prompt = """
     You have access to the following tools:
     """
@@ -449,7 +509,21 @@ def add_tool_instructions(self, tools: list) -> str:
 
         return tool_prompt
 
-    def add_function_instructions(self, functions: list) -> str:
+    def build_function_instructions(self, functions: list) -> str:
+        """
+        Builds a detailed instructional prompt for available functions.
+
+        This method creates a message describing the functions accessible to the assistant.
+        It includes the function name, description, and required parameters, along with
+        specific guidelines for calling functions.
+
+        Args:
+            functions (list): A list of function dictionaries, each containing details such as
+            name, description, and parameters.
+
+        Returns:
+            str: A formatted string with instructions on using the provided functions.
+        """
         function_prompt = """
 You have access to the following functions:
 """
@@ -479,35 +553,60 @@ def add_function_instructions(self, functions: list) -> str:
 """
         return function_prompt
 
-    def add_conversation(self, openai_message: list, llama_message: str) -> str:
+    def build_llama_conversation(self, openai_message: list, llama_message: str) -> str:
+        """
+        Appends the OpenAI message to the Llama message while formatting OpenAI messages.
+
+        This function iterates through a list of OpenAI messages and formats them for inclusion
+        in a Llama message. It handles user messages that might include nested content (lists of
+        messages) by safely evaluating the content. System messages are skipped.
+
+        Args:
+            openai_message (list): A list of dictionaries representing the OpenAI messages. Each
+                                dictionary should have "role" and "content" keys.
+            llama_message (str): The initial Llama message to which the conversation is appended.
+
+        Returns:
+            str: The Llama message with the conversation appended.
+        """
         conversation_parts = []
         for message in openai_message:
             if message["role"] == "system":
                 continue
             elif message["role"] == "user" and isinstance(message["content"], str):
                 try:
-                    # Attempt to safely evaluate the string to a Python object
                     content_as_list = ast.literal_eval(message["content"])
                     if isinstance(content_as_list, list):
-                        # If the content is a list, process each nested message
                         for nested_message in content_as_list:
                             conversation_parts.append(
                                 self.format_message(nested_message)
                             )
                     else:
-                        # If the content is not a list, append it directly
                         conversation_parts.append(self.format_message(message))
                 except (ValueError, SyntaxError):
-                    # If evaluation fails or content is not a list/dict string, append the message directly
                     conversation_parts.append(self.format_message(message))
             else:
-                # For all other messages, use the existing formatting logic
                 conversation_parts.append(self.format_message(message))
 
         return llama_message + "".join(conversation_parts)
 
     def format_message(self, message: dict) -> str:
-        """Format a single message for the conversation."""
+        """
+        Formats a single message dictionary into a structured string for a conversation.
+
+        The formatting depends on the content of the message, such as tool calls,
+        function calls, or simple user/assistant messages. Each type of message
+        is formatted with specific headers and tags.
+
+        Args:
+            message (dict): A dictionary containing message details. Expected keys
+                            include "role", "content", and optionally "tool_calls",
+                            "tool_call_id", or "function_call".
+
+        Returns:
+            str: A formatted string representing the message. Returns an empty
+            string if the message cannot be formatted.
+        """
         if "tool_calls" in message:
             for tool_call in message["tool_calls"]:
                 function_name = tool_call["function"]["name"]
diff --git a/libs/core/llmstudio_core/providers/provider.py b/libs/core/llmstudio_core/providers/provider.py
index 07e03835..69a673dd 100644
--- a/libs/core/llmstudio_core/providers/provider.py
+++ b/libs/core/llmstudio_core/providers/provider.py
@@ -152,8 +152,38 @@ async def achat(
         parameters: Optional[dict] = {},
         **kwargs,
     ):
-
-        """Makes a chat connection with the provider's API"""
+        """
+        Asynchronously establishes a chat connection with the provider’s API, handling retries,
+        request validation, and streaming response options.
+
+        Parameters
+        ----------
+        chat_input : Any
+            The input data for the chat request, such as a string or dictionary, to be sent to the API.
+        model : str
+            The identifier of the model to be used for the chat request.
+        is_stream : Optional[bool], default=False
+            Flag to indicate if the response should be streamed. If True, returns an async generator
+            for streaming content; otherwise, returns the complete response.
+        retries : Optional[int], default=0
+            Number of retry attempts on error. Retries will be attempted for specific HTTP errors like rate limits.
+        parameters : Optional[dict], default={}
+            Additional configuration parameters for the request, such as temperature or max tokens.
+        **kwargs
+            Additional keyword arguments to customize the request.
+
+        Returns
+        -------
+        Union[AsyncGenerator, Any]
+            - If `is_stream` is True, returns an async generator yielding response chunks.
+            - If `is_stream` is False, returns the first complete response chunk.
+
+        Raises
+        ------
+        ProviderError
+            - Raised if the request validation fails or if all retry attempts are exhausted.
+            - Also raised for unexpected exceptions during request handling.
+        """
         try:
             request = self.validate_request(
                 dict(
@@ -198,8 +228,38 @@ def chat(
         parameters: Optional[dict] = {},
         **kwargs,
     ):
-
-        """Makes a chat connection with the provider's API"""
+        """
+        Establishes a chat connection with the provider’s API, handling retries, request validation,
+        and streaming response options.
+
+        Parameters
+        ----------
+        chat_input : Any
+            The input data for the chat request, often a string or dictionary, to be sent to the API.
+        model : str
+            The model identifier for selecting the model used in the chat request.
+        is_stream : Optional[bool], default=False
+            Flag to indicate if the response should be streamed. If True, the function returns a generator
+            for streaming content. Otherwise, it returns the complete response.
+        retries : Optional[int], default=0
+            Number of retry attempts on error. Retries will be attempted on specific HTTP errors like rate limits.
+        parameters : Optional[dict], default={}
+            Additional configuration parameters for the request, such as temperature or max tokens.
+        **kwargs
+            Additional keyword arguments that can be passed to customize the request.
+
+        Returns
+        -------
+        Union[Generator, Any]
+            - If `is_stream` is True, returns a generator that yields chunks of the response.
+            - If `is_stream` is False, returns the first complete response chunk.
+
+        Raises
+        ------
+        ProviderError
+            - Raised if the request validation fails or if the request fails after the specified number of retries.
+            - Also raised on other unexpected exceptions during request handling.
+        """
         try:
             request = self.validate_request(
                 dict(
@@ -238,7 +298,28 @@ def chat(
     async def ahandle_response(
         self, request: ChatRequest, response: AsyncGenerator, start_time: float
     ) -> AsyncGenerator[str, None]:
-        """Handles the response from an API"""
+        """
+        Asynchronously handles the response from an API, processing response chunks for either
+        streaming or non-streaming responses.
+
+        Buffers response chunks for non-streaming responses to output one single message. For streaming responses sends incremental chunks.
+
+        Parameters
+        ----------
+        request : ChatRequest
+            The chat request object, which includes input data, model name, and streaming options.
+        response : AsyncGenerator
+            The async generator yielding response chunks from the API.
+        start_time : float
+            The timestamp when the response handling started, used for latency calculations.
+
+        Yields
+        ------
+        Union[ChatCompletionChunk, ChatCompletion]
+            - If `request.is_stream` is True, yields `ChatCompletionChunk` objects with incremental
+            response chunks for streaming.
+            - If `request.is_stream` is False, yields a final `ChatCompletion` object after processing all chunks.
+        """
         first_token_time = None
         previous_token_time = None
         token_times = []
@@ -294,7 +375,7 @@ async def ahandle_response(
         chunks = [chunk[0] if isinstance(chunk, tuple) else chunk for chunk in chunks]
         model = next(chunk["model"] for chunk in chunks if chunk.get("model"))
 
-        response, output_string = self.join_chunks(chunks, request)
+        response, output_string = self.join_chunks(chunks)
 
         metrics = self.calculate_metrics(
             request.chat_input,
@@ -346,7 +427,29 @@ async def ahandle_response(
     def handle_response(
         self, request: ChatRequest, response: Generator, start_time: float
     ) -> Generator:
-        """Handles the response from an API"""
+        """
+        Processes API response chunks to build a structured, complete response, yielding
+        each chunk if streaming is enabled.
+
+        If streaming, each chunk is yielded as soon as it’s processed. Otherwise, all chunks
+        are combined and yielded as a single response at the end.
+
+        Parameters
+        ----------
+        request : ChatRequest
+            The original request details, including model, input, and streaming preference.
+        response : Generator
+            A generator yielding partial response chunks from the API.
+        start_time : float
+            The start time for measuring response timing.
+
+        Yields
+        ------
+        Union[ChatCompletionChunk, ChatCompletion]
+            If streaming (`is_stream=True`), yields each `ChatCompletionChunk` as it’s processed.
+            Otherwise, yields a single `ChatCompletion` with the full response data.
+
+        """
         first_token_time = None
         previous_token_time = None
         token_times = []
@@ -402,7 +505,7 @@ def handle_response(
         chunks = [chunk[0] if isinstance(chunk, tuple) else chunk for chunk in chunks]
         model = next(chunk["model"] for chunk in chunks if chunk.get("model"))
 
-        response, output_string = self.join_chunks(chunks, request)
+        response, output_string = self.join_chunks(chunks)
 
         metrics = self.calculate_metrics(
             request.chat_input,
@@ -451,7 +554,29 @@ def handle_response(
         else:
             yield ChatCompletion(**response)
 
-    def join_chunks(self, chunks, request):
+    def join_chunks(self, chunks):
+        """
+        Combine multiple response chunks from the model into a single, structured response.
+        Handles tool calls, function calls, and standard text completion based on the
+        purpose indicated by the final chunk.
+
+        Parameters
+        ----------
+        chunks : List[Dict]
+            A list of partial responses (chunks) from the model.
+
+        Returns
+        -------
+        Tuple[ChatCompletion, str]
+            - `ChatCompletion`: The structured response based on the type of completion
+            (tool calls, function call, or text).
+            - `str`: The concatenated content or arguments, depending on the completion type.
+
+        Raises
+        ------
+        Exception
+            If there is an issue constructing the response, an exception is raised.
+        """
 
         finish_reason = chunks[-1].get("choices")[0].get("finish_reason")
         if finish_reason == "tool_calls":
@@ -612,7 +737,42 @@ def calculate_metrics(
         token_times: Tuple[float, ...],
         token_count: int,
     ) -> Dict[str, Any]:
-        """Calculates metrics based on token times and output"""
+        """
+        Calculates performance and cost metrics for a model response based on timing
+        information, token counts, and model-specific costs.
+
+        Parameters
+        ----------
+        input : Any
+            The input provided to the model, used to determine input token count.
+        output : Any
+            The output generated by the model, used to determine output token count.
+        model : str
+            The model identifier, used to retrieve model-specific configuration and costs.
+        start_time : float
+            The timestamp marking the start of the model response.
+        end_time : float
+            The timestamp marking the end of the model response.
+        first_token_time : float
+            The timestamp when the first token was received, used for latency calculations.
+        token_times : Tuple[float, ...]
+            A tuple of time intervals between received tokens, used for inter-token latency.
+        token_count : int
+            The total number of tokens processed in the response.
+
+        Returns
+        -------
+        Dict[str, Any]
+            A dictionary containing calculated metrics, including:
+            - `input_tokens`: Number of tokens in the input.
+            - `output_tokens`: Number of tokens in the output.
+            - `total_tokens`: Total token count (input + output).
+            - `cost_usd`: Total cost of the response in USD.
+            - `latency_s`: Total time taken for the response, in seconds.
+            - `time_to_first_token_s`: Time to receive the first token, in seconds.
+            - `inter_token_latency_s`: Average time between tokens, in seconds. If `token_times` is empty sets it to 0.
+            - `tokens_per_second`: Processing rate of tokens per second.
+        """
         model_config = self.config.models[model]
         input_tokens = len(self.tokenizer.encode(self.input_to_string(input)))
         output_tokens = len(self.tokenizer.encode(self.output_to_string(output)))
@@ -628,17 +788,42 @@ def calculate_metrics(
             "cost_usd": input_cost + output_cost,
             "latency_s": total_time,
             "time_to_first_token_s": first_token_time - start_time,
-            "inter_token_latency_s": sum(token_times) / len(token_times),
-            "tokens_per_second": token_count / total_time,
+            "inter_token_latency_s": sum(token_times) / len(token_times)
+            if token_times
+            else 0,
+            "tokens_per_second": token_count / total_time
+            if token_times
+            else 1 / total_time,
         }
 
     def calculate_cost(
         self, token_count: int, token_cost: Union[float, List[Dict[str, Any]]]
     ) -> float:
+        """
+        Calculates the cost for a given number of tokens based on a fixed cost per token
+        or a variable rate structure.
+
+        If `token_cost` is a fixed float, the total cost is `token_count * token_cost`.
+        If `token_cost` is a list, it checks each range and calculates cost based on the applicable range's rate.
+
+        Parameters
+        ----------
+        token_count : int
+            The total number of tokens for which the cost is being calculated.
+        token_cost : Union[float, List[Dict[str, Any]]]
+            Either a fixed cost per token (as a float) or a list of dictionaries defining
+            variable cost ranges. Each dictionary in the list represents a range with
+            'range' (a tuple of minimum and maximum token counts) and 'cost' (cost per token) keys.
+
+        Returns
+        -------
+        float
+            The calculated cost based on the token count and cost structure.
+        """
         if isinstance(token_cost, list):
             for cost_range in token_cost:
                 if token_count >= cost_range.range[0] and (
-                    token_count <= cost_range.range[1] or cost_range.range[1] is None
+                    cost_range.range[1] is None or token_count <= cost_range.range[1]
                 ):
                     return cost_range.cost * token_count
         else:
@@ -646,6 +831,23 @@ def calculate_cost(
         return 0
 
     def input_to_string(self, input):
+        """
+        Converts an input, which can be a string or a structured list of messages, into a single concatenated string.
+
+        Parameters
+        ----------
+        input : Any
+            The input data to be converted. This can be:
+            - A simple string, which is returned as-is.
+            - A list of message dictionaries, where each dictionary may contain `content`, `role`,
+            and nested items like `text` or `image_url`.
+
+        Returns
+        -------
+        str
+            A concatenated string representing the text content of all messages,
+            including text and URLs from image content if present.
+        """
         if isinstance(input, str):
             return input
         else:
@@ -667,6 +869,23 @@ def input_to_string(self, input):
             return "".join(result)
 
     def output_to_string(self, output):
+        """
+        Extracts and returns the content or arguments from the output based on
+        the `finish_reason` of the first choice in `output`.
+
+        Parameters
+        ----------
+        output : Any
+            The model output object, expected to have a `choices` attribute that should contain a `finish_reason` indicating the type of output
+            ("stop", "tool_calls", or "function_call") and corresponding content or arguments.
+
+        Returns
+        -------
+        str
+            - If `finish_reason` is "stop": Returns the message content.
+            - If `finish_reason` is "tool_calls": Returns the arguments for the first tool call.
+            - If `finish_reason` is "function_call": Returns the arguments for the function call.
+        """
         if output.choices[0].finish_reason == "stop":
             return output.choices[0].message.content
         elif output.choices[0].finish_reason == "tool_calls":
diff --git a/libs/core/tests/unit_tests/conftest.py b/libs/core/tests/unit_tests/conftest.py
index 23f070e3..5eeccc83 100644
--- a/libs/core/tests/unit_tests/conftest.py
+++ b/libs/core/tests/unit_tests/conftest.py
@@ -1,6 +1,7 @@
 from unittest.mock import MagicMock
 
 import pytest
+from llmstudio_core.providers.azure import AzureProvider
 from llmstudio_core.providers.provider import ProviderCore
 
 
@@ -11,14 +12,6 @@ async def aparse_response(self, response, **kwargs):
     def parse_response(self, response, **kwargs):
         return response
 
-    def chat(self, chat_input, model, **kwargs):
-        # Mock the response to match expected structure
-        return MagicMock(choices=[MagicMock(finish_reason="stop")])
-
-    async def achat(self, chat_input, model, **kwargs):
-        # Mock the response to match expected structure
-        return MagicMock(choices=[MagicMock(finish_reason="stop")])
-
     def output_to_string(self, output):
         # Handle string inputs
         if isinstance(output, str):
@@ -27,6 +20,24 @@ def output_to_string(self, output):
             return output.choices[0].message.content
         return ""
 
+    def validate_request(self, request):
+        # For testing, simply return the request
+        return request
+
+    async def agenerate_client(self, request):
+        # For testing, return an async generator
+        async def async_gen():
+            yield {}
+
+        return async_gen()
+
+    def generate_client(self, request):
+        # For testing, return a generator
+        def gen():
+            yield {}
+
+        return gen()
+
     @staticmethod
     def _provider_config_name():
         return "mock_provider"
@@ -42,3 +53,27 @@ def mock_provider():
     tokenizer = MagicMock()
     tokenizer.encode = lambda x: x.split()  # Simple tokenizer mock
     return MockProvider(config=config, tokenizer=tokenizer)
+
+
+class MockAzureProvider(AzureProvider):
+    async def aparse_response(self, response, **kwargs):
+        return response
+
+    async def agenerate_client(self, request):
+        # For testing, return an async generator
+        async def async_gen():
+            yield {}
+
+        return async_gen()
+
+    @staticmethod
+    def _provider_config_name():
+        return "mock_azure_provider"
+
+
+@pytest.fixture
+def mock_azure_provider():
+    config = MagicMock()
+    config.id = "mock_azure_provider"
+    base_url = "mock_url.com"
+    return MockAzureProvider(config=config, base_url=base_url)
diff --git a/libs/core/tests/unit_tests/test_azure.py b/libs/core/tests/unit_tests/test_azure.py
new file mode 100644
index 00000000..28e5f684
--- /dev/null
+++ b/libs/core/tests/unit_tests/test_azure.py
@@ -0,0 +1,232 @@
+from unittest.mock import MagicMock
+
+
+class TestParseResponse:
+    def test_tool_response_handling(self, mock_azure_provider):
+
+        mock_azure_provider.is_llama = True
+        mock_azure_provider.has_tools = True
+        mock_azure_provider.has_functions = False
+
+        mock_azure_provider.handle_tool_response = MagicMock(
+            return_value=iter(["chunk1", None, "chunk2", None, "chunk3"])
+        )
+
+        response = iter(["irrelevant"])
+
+        results = list(mock_azure_provider.parse_response(response))
+
+        assert results == ["chunk1", "chunk2", "chunk3"]
+        mock_azure_provider.handle_tool_response.assert_called_once_with(response)
+
+    def test_direct_response_handling_with_choices(self, mock_azure_provider):
+        mock_azure_provider.is_llama = False
+
+        chunk1 = MagicMock()
+        chunk1.model_dump.return_value = {"choices": ["choice1", "choice2"]}
+        chunk2 = MagicMock()
+        chunk2.model_dump.return_value = {"choices": ["choice2"]}
+        response = iter([chunk1, chunk2])
+
+        results = list(mock_azure_provider.parse_response(response))
+
+        assert results == [
+            {"choices": ["choice1", "choice2"]},
+            {"choices": ["choice2"]},
+        ]
+        chunk1.model_dump.assert_called_once()
+        chunk2.model_dump.assert_called_once()
+
+    def test_direct_response_handling_without_choices(self, mock_azure_provider):
+        mock_azure_provider.is_llama = False
+
+        chunk1 = MagicMock()
+        chunk1.model_dump.return_value = {"key": "value"}
+        chunk2 = MagicMock()
+        chunk2.model_dump.return_value = {"another_key": "another_value"}
+        response = iter([chunk1, chunk2])
+
+        results = list(mock_azure_provider.parse_response(response))
+
+        assert results == []
+        chunk1.model_dump.assert_called_once()
+        chunk2.model_dump.assert_called_once()
+
+
+class TestFormatMessage:
+    def test_format_message_tool_calls(self, mock_azure_provider):
+        message = {
+            "tool_calls": [
+                {
+                    "function": {
+                        "name": "example_tool",
+                        "arguments": '{"arg1": "value1"}',
+                    }
+                }
+            ]
+        }
+        result = mock_azure_provider.format_message(message)
+        expected = """
+        <|start_header_id|>assistant<|end_header_id|>
+        <function=example_tool>{"arg1": "value1"}</function>
+        <|eom_id|>
+            """
+        assert result.strip() == expected.strip()
+
+    def test_format_message_tool_call_id(self, mock_azure_provider):
+        message = {"tool_call_id": "123", "content": "This is the tool response."}
+        result = mock_azure_provider.format_message(message)
+        expected = """
+    <|start_header_id|>ipython<|end_header_id|>
+    This is the tool response.
+    <|eot_id|>
+        """
+        assert result.strip() == expected.strip()
+
+    def test_format_message_function_call(self, mock_azure_provider):
+        message = {
+            "function_call": {
+                "name": "example_function",
+                "arguments": '{"arg1": "value1"}',
+            }
+        }
+        result = mock_azure_provider.format_message(message)
+        expected = """
+        <|start_header_id|>assistant<|end_header_id|>
+        <function=example_function>{"arg1": "value1"}</function>
+        <|eom_id|>
+            """
+        assert result.strip() == expected.strip()
+
+    def test_format_message_user_message(self, mock_azure_provider):
+        message = {"role": "user", "content": "This is a user message."}
+        result = mock_azure_provider.format_message(message)
+        expected = """
+    <|start_header_id|>user<|end_header_id|>
+    This is a user message.
+    <|eot_id|>
+        """
+        assert result.strip() == expected.strip()
+
+    def test_format_message_assistant_message(self, mock_azure_provider):
+        message = {"role": "assistant", "content": "This is an assistant message."}
+        result = mock_azure_provider.format_message(message)
+        expected = """
+    <|start_header_id|>assistant<|end_header_id|>
+    This is an assistant message.
+    <|eot_id|>
+        """
+        assert result.strip() == expected.strip()
+
+    def test_format_message_function_response(self, mock_azure_provider):
+        message = {"role": "function", "content": "This is the function response."}
+        result = mock_azure_provider.format_message(message)
+        expected = """
+    <|start_header_id|>ipython<|end_header_id|>
+    This is the function response.
+    <|eot_id|>
+        """
+        assert result.strip() == expected.strip()
+
+    def test_format_message_empty_message(self, mock_azure_provider):
+        message = {"role": "user", "content": None}
+        result = mock_azure_provider.format_message(message)
+        expected = ""
+        assert result == expected
+
+
+class TestGenerateClient:
+    def test_generate_client_with_tools_and_functions(self, mock_azure_provider):
+        mock_azure_provider.prepare_messages = MagicMock(
+            return_value="prepared_messages"
+        )
+        mock_azure_provider._client.chat.completions.create = MagicMock(
+            return_value="mock_response"
+        )
+
+        request = MagicMock()
+        request.model = "gpt-4"
+        request.parameters = {
+            "tools": ["tool1", "tool2"],
+            "functions": ["function1", "function2"],
+            "other_param": "value",
+        }
+
+        result = mock_azure_provider.generate_client(request)
+
+        expected_args = {
+            "model": "gpt-4",
+            "messages": "prepared_messages",
+            "stream": True,
+            "tools": ["tool1", "tool2"],
+            "tool_choice": "auto",
+            "functions": ["function1", "function2"],
+            "function_call": "auto",
+            "other_param": "value",
+        }
+
+        assert result == "mock_response"
+        mock_azure_provider.prepare_messages.assert_called_once_with(request)
+        mock_azure_provider._client.chat.completions.create.assert_called_once_with(
+            **expected_args
+        )
+
+    def test_generate_client_without_tools_or_functions(self, mock_azure_provider):
+        mock_azure_provider.prepare_messages = MagicMock(
+            return_value="prepared_messages"
+        )
+        mock_azure_provider._client.chat.completions.create = MagicMock(
+            return_value="mock_response"
+        )
+
+        request = MagicMock()
+        request.model = "gpt-4"
+        request.parameters = {"other_param": "value"}
+
+        result = mock_azure_provider.generate_client(request)
+
+        expected_args = {
+            "model": "gpt-4",
+            "messages": "prepared_messages",
+            "stream": True,
+            "other_param": "value",
+        }
+
+        assert result == "mock_response"
+        mock_azure_provider.prepare_messages.assert_called_once_with(request)
+        mock_azure_provider._client.chat.completions.create.assert_called_once_with(
+            **expected_args
+        )
+
+    def test_generate_client_with_llama_model(self, mock_azure_provider):
+        mock_azure_provider.prepare_messages = MagicMock(
+            return_value="prepared_messages"
+        )
+        mock_azure_provider._client.chat.completions.create = MagicMock(
+            return_value="mock_response"
+        )
+
+        request = MagicMock()
+        request.model = "llama-2"
+        request.parameters = {
+            "tools": ["tool1"],
+            "functions": ["function1"],
+            "other_param": "value",
+        }
+
+        result = mock_azure_provider.generate_client(request)
+
+        expected_args = {
+            "model": "llama-2",
+            "messages": "prepared_messages",
+            "stream": True,
+            "tools": ["tool1"],
+            "functions": ["function1"],
+            "other_param": "value",
+        }
+
+        assert result == "mock_response"
+        mock_azure_provider.prepare_messages.assert_called_once_with(request)
+        mock_azure_provider._client.chat.completions.create.assert_called_once_with(
+            **expected_args
+        )
diff --git a/libs/core/tests/unit_tests/test_azure_build.py b/libs/core/tests/unit_tests/test_azure_build.py
new file mode 100644
index 00000000..17d73f99
--- /dev/null
+++ b/libs/core/tests/unit_tests/test_azure_build.py
@@ -0,0 +1,279 @@
+from unittest.mock import MagicMock, patch
+
+
+class TestBuildLlamaSystemMessage:
+    def test_build_llama_system_message_with_existing_sm(self, mock_azure_provider):
+        mock_azure_provider.build_tool_instructions = MagicMock(
+            return_value="Tool Instructions"
+        )
+        mock_azure_provider.build_function_instructions = MagicMock(
+            return_value="\nFunction Instructions"
+        )
+
+        openai_message = [
+            {"role": "user", "content": "Hello"},
+            {"role": "system", "content": "Custom system message"},
+        ]
+        llama_message = "Initial message"
+        tools = ["Tool1", "Tool2"]
+        functions = ["Function1"]
+
+        result = mock_azure_provider.build_llama_system_message(
+            openai_message, llama_message, tools, functions
+        )
+
+        expected = (
+            "Initial message\n"
+            "        <|start_header_id|>system<|end_header_id|>\n"
+            "        Custom system message\n"
+            "        Tool Instructions\nFunction Instructions\n<|eot_id|>"  # identation here exists because in Python when adding a newline to a triple quote string it keeps identation
+        )
+        assert result == expected
+        mock_azure_provider.build_tool_instructions.assert_called_once_with(tools)
+        mock_azure_provider.build_function_instructions.assert_called_once_with(
+            functions
+        )
+
+    def test_build_llama_system_message_with_default_sm(self, mock_azure_provider):
+        mock_azure_provider.build_tool_instructions = MagicMock(
+            return_value="Tool Instructions"
+        )
+        mock_azure_provider.build_function_instructions = MagicMock(
+            return_value="\nFunction Instructions"
+        )
+
+        openai_message = [{"role": "user", "content": "Hello"}]
+        llama_message = "Initial message"
+        tools = ["Tool1"]
+        functions = []
+
+        result = mock_azure_provider.build_llama_system_message(
+            openai_message, llama_message, tools, functions
+        )
+
+        expected = (
+            "Initial message\n"
+            "      <|start_header_id|>system<|end_header_id|>\n"
+            "      You are a helpful AI assistant.\n"
+            "      Tool Instructions\n<|eot_id|>"
+        )
+        assert result == expected
+        mock_azure_provider.build_tool_instructions.assert_called_once_with(tools)
+        mock_azure_provider.build_function_instructions.assert_not_called()
+
+    def test_build_llama_system_message_without_tools_or_functions(
+        self, mock_azure_provider
+    ):
+        mock_azure_provider.build_tool_instructions = MagicMock()
+        mock_azure_provider.build_function_instructions = MagicMock()
+
+        openai_message = [{"role": "system", "content": "Minimal system message"}]
+        llama_message = "Initial message"
+        tools = []
+        functions = []
+
+        result = mock_azure_provider.build_llama_system_message(
+            openai_message, llama_message, tools, functions
+        )
+
+        expected = (
+            "Initial message\n"
+            "        <|start_header_id|>system<|end_header_id|>\n"
+            "        Minimal system message\n        \n<|eot_id|>"
+        )
+        assert result == expected
+        mock_azure_provider.build_tool_instructions.assert_not_called()
+        mock_azure_provider.build_function_instructions.assert_not_called()
+
+
+class TestBuildInstructions:
+    def test_build_tool_instructions(self, mock_azure_provider):
+        tools = [
+            {
+                "type": "function",
+                "function": {
+                    "name": "python_repl_ast",
+                    "description": "execute Python code",
+                    "parameters": {"query": "string"},
+                },
+            },
+            {
+                "type": "function",
+                "function": {
+                    "name": "data_lookup",
+                    "description": "retrieve data from a database",
+                    "parameters": {"database": "string", "query": "string"},
+                },
+            },
+        ]
+
+        result = mock_azure_provider.build_tool_instructions(tools)
+
+        expected = """
+    You have access to the following tools:
+    Use the function 'python_repl_ast' to 'execute Python code':
+Parameters format:
+{
+    "query": "string"
+}
+
+Use the function 'data_lookup' to 'retrieve data from a database':
+Parameters format:
+{
+    "database": "string",
+    "query": "string"
+}
+
+
+If you choose to use a function to produce this response, ONLY reply in the following format with no prefix or suffix:
+§{"type": "function", "name": "FUNCTION_NAME", "parameters": {"PARAMETER_NAME": PARAMETER_VALUE}}
+IMPORTANT: IT IS VITAL THAT YOU NEVER ADD A PREFIX OR A SUFFIX TO THE FUNCTION CALL.
+
+Here is an example of the output I desiere when performing function call:
+§{"type": "function", "name": "python_repl_ast", "parameters": {"query": "print(df.shape)"}}
+NOTE: There is no prefix before the symbol '§' and nothing comes after the call is done.
+
+    Reminder:
+    - Function calls MUST follow the specified format.
+    - Only call one function at a time.
+    - Required parameters MUST be specified.
+    - Put the entire function call reply on one line.
+    - If there is no function call available, answer the question like normal with your current knowledge and do not tell the user about function calls.
+    - If you have already called a tool and got the response for the users question please reply with the response.
+    """
+        assert result.strip() == expected.strip()
+
+    def test_build_function_instructions(self, mock_azure_provider):
+        functions = [
+            {
+                "name": "python_repl_ast",
+                "description": "execute Python code",
+                "parameters": {"query": "string"},
+            },
+            {
+                "name": "data_lookup",
+                "description": "retrieve data from a database",
+                "parameters": {"database": "string", "query": "string"},
+            },
+        ]
+
+        result = mock_azure_provider.build_function_instructions(functions)
+
+        expected = """
+You have access to the following functions:
+Use the function 'python_repl_ast' to: 'execute Python code'
+{
+    "query": "string"
+}
+
+Use the function 'data_lookup' to: 'retrieve data from a database'
+{
+    "database": "string",
+    "query": "string"
+}
+
+
+If you choose to use a function to produce this response, ONLY reply in the following format with no prefix or suffix:
+§{"type": "function", "name": "FUNCTION_NAME", "parameters": {"PARAMETER_NAME": PARAMETER_VALUE}}
+
+Here is an example of the output I desiere when performing function call:
+§{"type": "function", "name": "python_repl_ast", "parameters": {"query": "print(df.shape)"}}
+
+Reminder:
+- Function calls MUST follow the specified format.
+- Only call one function at a time.
+- NEVER call more than one function at a time.
+- Required parameters MUST be specified.
+- Put the entire function call reply on one line.
+- If there is no function call available, answer the question like normal with your current knowledge and do not tell the user about function calls.
+- If you have already called a function and got the response for the user's question, please reply with the response.
+"""
+
+        assert result.strip() == expected.strip()
+
+
+class TestBuildLlamaConversation:
+    def test_build_llama_conversation_with_nested_messages(self, mock_azure_provider):
+        mock_azure_provider.format_message = MagicMock(
+            side_effect=lambda msg: f"[formatted:{msg['content']}]"
+        )
+
+        openai_message = [
+            {
+                "role": "user",
+                "content": "[{'content': 'nested message 1'}, {'content': 'nested message 2'}]",
+            },
+            {"role": "assistant", "content": "assistant reply"},
+        ]
+        llama_message = "Initial message: "
+
+        result = mock_azure_provider.build_llama_conversation(
+            openai_message, llama_message
+        )
+
+        expected = "Initial message: [formatted:nested message 1][formatted:nested message 2][formatted:assistant reply]"
+
+        assert result == expected
+        mock_azure_provider.format_message.assert_any_call(
+            {"content": "nested message 1"}
+        )
+        mock_azure_provider.format_message.assert_any_call(
+            {"content": "nested message 2"}
+        )
+        mock_azure_provider.format_message.assert_any_call(
+            {"role": "assistant", "content": "assistant reply"}
+        )
+
+    def test_build_llama_conversation_with_invalid_nested_content(
+        self, mock_azure_provider
+    ):
+        mock_azure_provider.format_message = MagicMock(
+            side_effect=lambda msg: f"[formatted:{msg['content']}]"
+        )
+
+        openai_message = [
+            {"role": "user", "content": "[invalid json/dict]"},
+            {"role": "assistant", "content": "assistant reply"},
+        ]
+        llama_message = "Initial message: "
+
+        with patch("ast.literal_eval", side_effect=ValueError) as mock_literal_eval:
+            result = mock_azure_provider.build_llama_conversation(
+                openai_message, llama_message
+            )
+
+            expected = "Initial message: [formatted:[invalid json/dict]][formatted:assistant reply]"
+
+            assert result == expected
+            mock_azure_provider.format_message.assert_any_call(
+                {"role": "user", "content": "[invalid json/dict]"}
+            )
+            mock_azure_provider.format_message.assert_any_call(
+                {"role": "assistant", "content": "assistant reply"}
+            )
+
+            mock_literal_eval.assert_called_once_with("[invalid json/dict]")
+
+    def test_build_llama_conversation_skipping_system_messages(
+        self, mock_azure_provider
+    ):
+        mock_azure_provider.format_message = MagicMock(
+            side_effect=lambda msg: f"[formatted:{msg['content']}]"
+        )
+
+        openai_message = [
+            {"role": "system", "content": "system message"},
+            {"role": "user", "content": "user message"},
+        ]
+        llama_message = "Initial message: "
+
+        result = mock_azure_provider.build_llama_conversation(
+            openai_message, llama_message
+        )
+
+        expected = "Initial message: [formatted:user message]"
+
+        assert result == expected
+        mock_azure_provider.format_message.assert_any_call(
+            {"role": "user", "content": "user message"}
+        )
diff --git a/libs/core/tests/unit_tests/test_provider.py b/libs/core/tests/unit_tests/test_provider.py
index 118367a3..42396c99 100644
--- a/libs/core/tests/unit_tests/test_provider.py
+++ b/libs/core/tests/unit_tests/test_provider.py
@@ -1,30 +1,39 @@
-from unittest.mock import AsyncMock, MagicMock
+from unittest.mock import MagicMock
 
 import pytest
-from llmstudio_core.providers.provider import ChatRequest, ProviderError
+from llmstudio_core.providers.provider import ChatRequest, ProviderError, time
 
-request = ChatRequest(chat_input="Hello", model="test_model")
+request = ChatRequest(chat_input="Hello World", model="test_model")
 
 
-def test_chat(mock_provider):
-    mock_provider.generate_client = MagicMock(return_value=MagicMock())
-    mock_provider.handle_response = MagicMock(return_value=iter(["response"]))
+def test_chat_response_non_stream(mock_provider):
+    mock_provider.validate_request = MagicMock()
+    mock_provider.validate_model = MagicMock()
+    mock_provider.generate_client = MagicMock(return_value="mock_response")
+    mock_provider.handle_response = MagicMock(return_value="final_response")
 
-    print(request.model_dump())
-    response = mock_provider.chat(request.chat_input, request.model)
+    response = mock_provider.chat(chat_input="Hello", model="test_model")
 
-    assert response is not None
+    assert response == "final_response"
+    mock_provider.validate_request.assert_called_once()
+    mock_provider.validate_model.assert_called_once()
 
 
-@pytest.mark.asyncio
-async def test_achat(mock_provider):
-    mock_provider.agenerate_client = AsyncMock(return_value=AsyncMock())
-    mock_provider.ahandle_response = AsyncMock(return_value=AsyncMock())
-
-    print(request.model_dump())
-    response = await mock_provider.achat(request.chat_input, request.model)
+def test_chat_streaming_response(mock_provider):
+    mock_provider.validate_request = MagicMock()
+    mock_provider.validate_model = MagicMock()
+    mock_provider.generate_client = MagicMock(return_value="mock_response_stream")
+    mock_provider.handle_response = MagicMock(
+        return_value=iter(["streamed_response_1", "streamed_response_2"])
+    )
 
-    assert response is not None
+    response_stream = mock_provider.chat(
+        chat_input="Hello", model="test_model", is_stream=True
+    )
+    assert next(response_stream) == "streamed_response_1"
+    assert next(response_stream) == "streamed_response_2"
+    mock_provider.validate_request.assert_called_once()
+    mock_provider.validate_model.assert_called_once()
 
 
 def test_validate_model(mock_provider):
@@ -36,22 +45,214 @@ def test_validate_model(mock_provider):
         mock_provider.validate_model(request_invalid)
 
 
-def test_calculate_metrics(mock_provider):
-    metrics = mock_provider.calculate_metrics(
-        input="Hello",
-        output="World",
-        model="test_model",
-        start_time=0,
-        end_time=1,
-        first_token_time=0.5,
-        token_times=(0.1, 0.2),
-        token_count=2,
-    )
+def test_join_chunks_finish_reason_stop(mock_provider):
+    current_time = int(time.time())
+    chunks = [
+        {
+            "id": "test_id",
+            "model": "test_model",
+            "created": current_time,
+            "choices": [
+                {
+                    "delta": {"content": "Hello, "},
+                    "finish_reason": None,
+                    "index": 0,
+                }
+            ],
+        },
+        {
+            "id": "test_id",
+            "model": "test_model",
+            "created": current_time,
+            "choices": [
+                {
+                    "delta": {"content": "world!"},
+                    "finish_reason": "stop",
+                    "index": 0,
+                }
+            ],
+        },
+    ]
+    response, output_string = mock_provider.join_chunks(chunks)
+
+    assert output_string == "Hello, world!"
+    assert response.choices[0].message.content == "Hello, world!"
+
+
+def test_join_chunks_finish_reason_function_call(mock_provider):
+    current_time = int(time.time())
+    chunks = [
+        {
+            "id": "test_id",
+            "model": "test_model",
+            "created": current_time,
+            "choices": [
+                {
+                    "delta": {
+                        "function_call": {"name": "my_function", "arguments": "arg1"}
+                    },
+                    "finish_reason": None,
+                    "index": 0,
+                }
+            ],
+        },
+        {
+            "id": "test_id",
+            "model": "test_model",
+            "created": current_time,
+            "choices": [
+                {
+                    "delta": {"function_call": {"arguments": "arg2"}},
+                    "finish_reason": "function_call",
+                    "index": 0,
+                }
+            ],
+        },
+        {
+            "id": "test_id",
+            "model": "test_model",
+            "created": current_time,
+            "choices": [
+                {
+                    "delta": {"function_call": {"arguments": "}"}},
+                    "finish_reason": "function_call",
+                    "index": 0,
+                }
+            ],
+        },
+    ]
+    response, output_string = mock_provider.join_chunks(chunks)
+
+    assert output_string == "arg1arg2"
+    assert response.choices[0].message.function_call.arguments == "arg1arg2"
+    assert response.choices[0].message.function_call.name == "my_function"
+
+
+def test_join_chunks_tool_calls(mock_provider):
+    current_time = int(time.time())
+
+    chunks = [
+        {
+            "id": "test_id_1",
+            "model": "test_model",
+            "created": current_time,
+            "choices": [
+                {
+                    "delta": {
+                        "tool_calls": [
+                            {
+                                "id": "tool_1",
+                                "index": 0,
+                                "function": {
+                                    "name": "search_tool",
+                                    "arguments": '{"query": "weather',
+                                },
+                                "type": "function",
+                            }
+                        ]
+                    },
+                    "finish_reason": None,
+                    "index": 0,
+                }
+            ],
+        },
+        {
+            "id": "test_id_2",
+            "model": "test_model",
+            "created": current_time,
+            "choices": [
+                {
+                    "delta": {
+                        "tool_calls": [
+                            {
+                                "id": "tool_1",
+                                "index": 0,
+                                "function": {
+                                    "name": "search_tool",
+                                    "arguments": ' details"}',
+                                },
+                            }
+                        ]
+                    },
+                    "finish_reason": "tool_calls",
+                    "index": 0,
+                }
+            ],
+        },
+    ]
+
+    response, output_string = mock_provider.join_chunks(chunks)
+
+    assert output_string == "['search_tool', '{\"query\": \"weather details\"}']"
+
+    assert response.object == "chat.completion"
+    assert response.choices[0].finish_reason == "tool_calls"
+    tool_call = response.choices[0].message.tool_calls[0]
+
+    assert tool_call.id == "tool_1"
+    assert tool_call.function.name == "search_tool"
+    assert tool_call.function.arguments == '{"query": "weather details"}'
+    assert tool_call.type == "function"
+
+
+def test_input_to_string_with_string(mock_provider):
+    input_data = "Hello, world!"
+    assert mock_provider.input_to_string(input_data) == "Hello, world!"
+
+
+def test_input_to_string_with_list_of_text_messages(mock_provider):
+    input_data = [
+        {"content": "Hello"},
+        {"content": " world!"},
+    ]
+    assert mock_provider.input_to_string(input_data) == "Hello world!"
+
+
+def test_input_to_string_with_list_of_text_and_url(mock_provider):
+    input_data = [
+        {"role": "user", "content": [{"type": "text", "text": "Hello "}]},
+        {
+            "role": "user",
+            "content": [
+                {
+                    "type": "image_url",
+                    "image_url": {"url": "http://example.com/image.jpg"},
+                }
+            ],
+        },
+        {"role": "user", "content": [{"type": "text", "text": " world!"}]},
+    ]
+    expected_output = "Hello http://example.com/image.jpg world!"
+    assert mock_provider.input_to_string(input_data) == expected_output
+
+
+def test_input_to_string_with_mixed_roles_and_missing_content(mock_provider):
+    input_data = [
+        {"role": "assistant", "content": "Admin text;"},
+        {"role": "user", "content": [{"type": "text", "text": "User text"}]},
+        {
+            "role": "user",
+            "content": [
+                {
+                    "type": "image_url",
+                    "image_url": {"url": "http://example.com/another.jpg"},
+                }
+            ],
+        },
+    ]
+    expected_output = "Admin text;User texthttp://example.com/another.jpg"
+    assert mock_provider.input_to_string(input_data) == expected_output
+
+
+def test_input_to_string_with_missing_content_key(mock_provider):
+    input_data = [
+        {"role": "user"},
+        {"role": "user", "content": [{"type": "text", "text": "Hello again"}]},
+    ]
+    expected_output = "Hello again"
+    assert mock_provider.input_to_string(input_data) == expected_output
+
 
-    assert metrics["input_tokens"] == pytest.approx(1)
-    assert metrics["output_tokens"] == pytest.approx(1)
-    assert metrics["cost_usd"] == pytest.approx(0.03)
-    assert metrics["latency_s"] == pytest.approx(1)
-    assert metrics["time_to_first_token_s"] == pytest.approx(0.5)
-    assert metrics["inter_token_latency_s"] == pytest.approx(0.15)
-    assert metrics["tokens_per_second"] == pytest.approx(2)
+def test_input_to_string_with_empty_list(mock_provider):
+    input_data = []
+    assert mock_provider.input_to_string(input_data) == ""
diff --git a/libs/core/tests/unit_tests/test_provider_costs_and_metrics.py b/libs/core/tests/unit_tests/test_provider_costs_and_metrics.py
new file mode 100644
index 00000000..fb54d602
--- /dev/null
+++ b/libs/core/tests/unit_tests/test_provider_costs_and_metrics.py
@@ -0,0 +1,128 @@
+from unittest.mock import MagicMock
+
+
+def test_calculate_metrics(mock_provider):
+
+    metrics = mock_provider.calculate_metrics(
+        input="Hello",
+        output="Hello World",
+        model="test_model",
+        start_time=0.0,
+        end_time=1.0,
+        first_token_time=0.5,
+        token_times=(0.1,),
+        token_count=2,
+    )
+
+    assert metrics["input_tokens"] == 1
+    assert metrics["output_tokens"] == 2
+    assert metrics["total_tokens"] == 3
+    assert metrics["cost_usd"] == 0.01 * 1 + 0.02 * 2  # input_cost + output_cost
+    assert metrics["latency_s"] == 1.0  # end_time - start_time
+    assert (
+        metrics["time_to_first_token_s"] == 0.5 - 0.0
+    )  # first_token_time - start_time
+    assert metrics["inter_token_latency_s"] == 0.1  # Average of token_times
+    assert metrics["tokens_per_second"] == 2 / 1.0  # token_count / total_time
+
+
+def test_calculate_metrics_single_token(mock_provider):
+
+    metrics = mock_provider.calculate_metrics(
+        input="Hello",
+        output="World",
+        model="test_model",
+        start_time=0.0,
+        end_time=1.0,
+        first_token_time=0.5,
+        token_times=(),
+        token_count=1,
+    )
+
+    assert metrics["input_tokens"] == 1
+    assert metrics["output_tokens"] == 1
+    assert metrics["total_tokens"] == 2
+    assert metrics["cost_usd"] == 0.01 * 1 + 0.02 * 1
+    assert metrics["latency_s"] == 1.0
+    assert metrics["time_to_first_token_s"] == 0.5 - 0.0
+    assert metrics["inter_token_latency_s"] == 0
+    assert metrics["tokens_per_second"] == 1 / 1.0
+
+
+def test_calculate_cost_fixed_cost(mock_provider):
+    fixed_cost = 0.02
+    token_count = 100
+    expected_cost = token_count * fixed_cost
+    assert mock_provider.calculate_cost(token_count, fixed_cost) == expected_cost
+
+
+def test_calculate_cost_variable_cost(mock_provider):
+    cost_range_1 = MagicMock()
+    cost_range_1.range = (0, 50)
+    cost_range_1.cost = 0.01
+
+    cost_range_2 = MagicMock()
+    cost_range_2.range = (51, 100)
+    cost_range_2.cost = 0.02
+
+    variable_cost = [cost_range_1, cost_range_2]
+    token_count = 75
+    expected_cost = token_count * 0.02
+    assert mock_provider.calculate_cost(token_count, variable_cost) == expected_cost
+
+
+def test_calculate_cost_variable_cost_higher_range(mock_provider):
+    cost_range_1 = MagicMock()
+    cost_range_1.range = (0, 50)
+    cost_range_1.cost = 0.01
+
+    cost_range_2 = MagicMock()
+    cost_range_2.range = (51, 100)
+    cost_range_2.cost = 0.02
+
+    cost_range_3 = MagicMock()
+    cost_range_3.range = (101, None)
+    cost_range_3.cost = 0.03
+
+    variable_cost = [cost_range_1, cost_range_2, cost_range_3]
+    token_count = 150
+    expected_cost = token_count * 0.03
+    assert mock_provider.calculate_cost(token_count, variable_cost) == expected_cost
+
+
+def test_calculate_cost_variable_cost_no_matching_range(mock_provider):
+    cost_range_1 = MagicMock()
+    cost_range_1.range = (0, 50)
+    cost_range_1.cost = 0.01
+
+    cost_range_2 = MagicMock()
+    cost_range_2.range = (51, 100)
+    cost_range_2.cost = 0.02
+
+    cost_range_3 = MagicMock()
+    cost_range_3.range = (101, 150)
+    cost_range_3.cost = 0.03
+
+    variable_cost = [cost_range_1, cost_range_2, cost_range_3]
+    token_count = 200
+    expected_cost = 0
+    assert mock_provider.calculate_cost(token_count, variable_cost) == expected_cost
+
+
+def test_calculate_cost_variable_cost_no_matching_range_inferior(mock_provider):
+    cost_range_1 = MagicMock()
+    cost_range_1.range = (10, 50)
+    cost_range_1.cost = 0.01
+
+    cost_range_2 = MagicMock()
+    cost_range_2.range = (51, 100)
+    cost_range_2.cost = 0.02
+
+    cost_range_3 = MagicMock()
+    cost_range_3.range = (101, 150)
+    cost_range_3.cost = 0.03
+
+    variable_cost = [cost_range_1, cost_range_2, cost_range_3]
+    token_count = 5
+    expected_cost = 0
+    assert mock_provider.calculate_cost(token_count, variable_cost) == expected_cost
diff --git a/libs/core/tests/unit_tests/test_provider_handle_response.py b/libs/core/tests/unit_tests/test_provider_handle_response.py
new file mode 100644
index 00000000..ac04e32b
--- /dev/null
+++ b/libs/core/tests/unit_tests/test_provider_handle_response.py
@@ -0,0 +1,281 @@
+from unittest.mock import MagicMock
+
+import pytest
+from llmstudio_core.providers.provider import ChatCompletion, ChatCompletionChunk, time
+
+
+@pytest.mark.asyncio
+async def test_ahandle_response_non_streaming(mock_provider):
+    request = MagicMock(
+        is_stream=False, chat_input="Hello", model="test_model", parameters={}
+    )
+    response_chunk = {
+        "choices": [
+            {
+                "delta": {"content": "Non-streamed response"},
+                "finish_reason": "stop",
+                "index": 0,
+            }
+        ],
+        "model": "test_model",
+    }
+    start_time = time.time()
+
+    async def mock_aparse_response(*args, **kwargs):
+        yield response_chunk
+
+    mock_provider.aparse_response = mock_aparse_response
+    mock_provider.join_chunks = MagicMock(
+        return_value=(
+            ChatCompletion(
+                id="id",
+                choices=[],
+                created=0,
+                model="test_model",
+                object="chat.completion",
+            ),
+            "Non-streamed response",
+        )
+    )
+    mock_provider.calculate_metrics = MagicMock(return_value={"input_tokens": 1})
+
+    response = []
+    async for chunk in mock_provider.ahandle_response(
+        request, mock_aparse_response(), start_time
+    ):
+        response.append(chunk)
+
+    assert isinstance(response[0], ChatCompletion)
+    assert response[0].choices == []
+    assert response[0].chat_output == "Non-streamed response"
+
+
+@pytest.mark.asyncio
+async def test_ahandle_response_streaming_length(mock_provider):
+    request = MagicMock(
+        is_stream=True, chat_input="Hello", model="test_model", parameters={}
+    )
+    response_chunk = {
+        "choices": [
+            {
+                "delta": {"content": "Streamed response"},
+                "finish_reason": "length",
+                "index": 0,
+            }
+        ],
+        "model": "test_model",
+        "object": "chat.completion.chunk",
+        "created": 0,
+    }
+    start_time = time.time()
+
+    async def mock_aparse_response(*args, **kwargs):
+        yield response_chunk
+
+    mock_provider.aparse_response = mock_aparse_response
+    mock_provider.join_chunks = MagicMock(
+        return_value=(
+            ChatCompletion(
+                id="id",
+                choices=[],
+                created=0,
+                model="test_model",
+                object="chat.completion",
+            ),
+            "Streamed response",
+        )
+    )
+    mock_provider.calculate_metrics = MagicMock(return_value={"input_tokens": 1})
+
+    response = []
+    async for chunk in mock_provider.ahandle_response(
+        request, mock_aparse_response(), start_time
+    ):
+        response.append(chunk)
+
+    assert isinstance(response[0], ChatCompletionChunk)
+    assert response[0].chat_output_stream == "Streamed response"
+
+
+@pytest.mark.asyncio
+async def test_ahandle_response_streaming_stop(mock_provider):
+    request = MagicMock(
+        is_stream=True, chat_input="Hello", model="test_model", parameters={}
+    )
+    response_chunk = {
+        "choices": [
+            {
+                "delta": {"content": "Streamed response"},
+                "finish_reason": "stop",
+                "index": 0,
+            }
+        ],
+        "model": "test_model",
+        "object": "chat.completion.chunk",
+        "created": 0,
+    }
+    start_time = time.time()
+
+    async def mock_aparse_response(*args, **kwargs):
+        yield response_chunk
+
+    mock_provider.aparse_response = mock_aparse_response
+    mock_provider.join_chunks = MagicMock(
+        return_value=(
+            ChatCompletion(
+                id="id",
+                choices=[],
+                created=0,
+                model="test_model",
+                object="chat.completion",
+            ),
+            "Streamed response",
+        )
+    )
+    mock_provider.calculate_metrics = MagicMock(return_value={"input_tokens": 1})
+
+    response = []
+    async for chunk in mock_provider.ahandle_response(
+        request, mock_aparse_response(), start_time
+    ):
+        response.append(chunk)
+
+    assert isinstance(response[0], ChatCompletionChunk)
+    assert response[0].chat_output == "Streamed response"
+
+
+def test_handle_response_non_streaming(mock_provider):
+    request = MagicMock(
+        is_stream=False, chat_input="Hello", model="test_model", parameters={}
+    )
+    response_chunk = {
+        "choices": [
+            {
+                "delta": {"content": "Non-streamed response"},
+                "finish_reason": "stop",
+                "index": 0,
+            }
+        ],
+        "model": "test_model",
+    }
+    start_time = time.time()
+
+    def mock_parse_response(*args, **kwargs):
+        yield response_chunk
+
+    mock_provider.aparse_response = mock_parse_response
+    mock_provider.join_chunks = MagicMock(
+        return_value=(
+            ChatCompletion(
+                id="id",
+                choices=[],
+                created=0,
+                model="test_model",
+                object="chat.completion",
+            ),
+            "Non-streamed response",
+        )
+    )
+    mock_provider.calculate_metrics = MagicMock(return_value={"input_tokens": 1})
+
+    response = []
+    for chunk in mock_provider.handle_response(
+        request, mock_parse_response(), start_time
+    ):
+        response.append(chunk)
+
+    assert isinstance(response[0], ChatCompletion)
+    assert response[0].choices == []
+    assert response[0].chat_output == "Non-streamed response"
+
+
+def test_handle_response_streaming_length(mock_provider):
+    request = MagicMock(
+        is_stream=True, chat_input="Hello", model="test_model", parameters={}
+    )
+    response_chunk = {
+        "choices": [
+            {
+                "delta": {"content": "Streamed response"},
+                "finish_reason": "length",
+                "index": 0,
+            }
+        ],
+        "model": "test_model",
+        "object": "chat.completion.chunk",
+        "created": 0,
+    }
+    start_time = time.time()
+
+    def mock_parse_response(*args, **kwargs):
+        yield response_chunk
+
+    mock_provider.aparse_response = mock_parse_response
+    mock_provider.join_chunks = MagicMock(
+        return_value=(
+            ChatCompletion(
+                id="id",
+                choices=[],
+                created=0,
+                model="test_model",
+                object="chat.completion",
+            ),
+            "Streamed response",
+        )
+    )
+    mock_provider.calculate_metrics = MagicMock(return_value={"input_tokens": 1})
+
+    response = []
+    for chunk in mock_provider.handle_response(
+        request, mock_parse_response(), start_time
+    ):
+        response.append(chunk)
+
+    assert isinstance(response[0], ChatCompletionChunk)
+    assert response[0].chat_output_stream == "Streamed response"
+
+
+def test_handle_response_streaming_stop(mock_provider):
+    request = MagicMock(
+        is_stream=True, chat_input="Hello", model="test_model", parameters={}
+    )
+    response_chunk = {
+        "choices": [
+            {
+                "delta": {"content": "Streamed response"},
+                "finish_reason": "stop",
+                "index": 0,
+            }
+        ],
+        "model": "test_model",
+        "object": "chat.completion.chunk",
+        "created": 0,
+    }
+    start_time = time.time()
+
+    def mock_parse_response(*args, **kwargs):
+        yield response_chunk
+
+    mock_provider.parse_response = mock_parse_response
+    mock_provider.join_chunks = MagicMock(
+        return_value=(
+            ChatCompletion(
+                id="id",
+                choices=[],
+                created=0,
+                model="test_model",
+                object="chat.completion",
+            ),
+            "Streamed response",
+        )
+    )
+    mock_provider.calculate_metrics = MagicMock(return_value={"input_tokens": 1})
+
+    response = []
+    for chunk in mock_provider.handle_response(
+        request, mock_parse_response(), start_time
+    ):
+        response.append(chunk)
+
+    assert isinstance(response[0], ChatCompletionChunk)
+    assert response[0].chat_output == "Streamed response"