diff --git a/tests/test_logging.py b/tests/test_logging.py
index 3b8fde3..f9f91d6 100644
--- a/tests/test_logging.py
+++ b/tests/test_logging.py
@@ -11,6 +11,8 @@
 from unittest.mock import Mock
 from unittest.mock import patch
 
+import pytest
+
 from ipsdk import heuristics
 from ipsdk import logging as ipsdk_logging
 from ipsdk import metadata
@@ -400,6 +402,15 @@ def test_set_level_with_none_string(self):
 
             mock_logger.setLevel.assert_called_once_with(ipsdk_logging.NONE)
 
+    def test_set_level_with_invalid_string_raises_type_error(self):
+        """Test set_level with invalid string raises TypeError."""
+        with patch("ipsdk.logging.get_logger") as mock_get_logger:
+            mock_logger = Mock()
+            mock_get_logger.return_value = mock_logger
+
+            with pytest.raises(TypeError, match="Invalid level string: INVALID"):
+                ipsdk_logging.set_level("INVALID")
+
 
 class TestSensitiveDataFiltering:
     """Test sensitive data filtering functions."""
diff --git a/tests/test_platform.py b/tests/test_platform.py
index 2da3837..ef0f5ab 100644
--- a/tests/test_platform.py
+++ b/tests/test_platform.py
@@ -549,6 +549,32 @@ def test_authenticate_user_request_error():
         mixin.authenticate_basicauth()
 
 
+def test_authenticate_basicauth_missing_credentials():
+    """Test authenticate_basicauth raises IpsdkError when user or password is None."""
+    mixin = AuthMixin()
+    mixin.user = None
+    mixin.password = None
+    mixin.client = Mock()
+
+    with pytest.raises(exceptions.IpsdkError) as exc_info:
+        mixin.authenticate_basicauth()
+
+    assert "Username and password are required" in str(exc_info.value)
+
+
+def test_authenticate_oauth_missing_credentials():
+    """Test authenticate_oauth raises IpsdkError with missing credentials."""
+    mixin = AuthMixin()
+    mixin.client_id = None
+    mixin.client_secret = None
+    mixin.client = Mock()
+
+    with pytest.raises(exceptions.IpsdkError) as exc_info:
+        mixin.authenticate_oauth()
+
+    assert "Client ID and client secret are required" in str(exc_info.value)
+
+
 def test_authenticate_no_credentials_error():
     """Test authenticate raises IpsdkError when no credentials provided."""
     mixin = AuthMixin()
@@ -755,6 +781,34 @@ async def test_async_authenticate_basicauth_request_error():
         await mixin.authenticate_basicauth()
 
 
+@pytest.mark.asyncio
+async def test_async_authenticate_basicauth_missing_credentials():
+    """Test async authenticate_basicauth raises IpsdkError with missing creds."""
+    mixin = AsyncAuthMixin()
+    mixin.user = None
+    mixin.password = None
+    mixin.client = AsyncMock()
+
+    with pytest.raises(exceptions.IpsdkError) as exc_info:
+        await mixin.authenticate_basicauth()
+
+    assert "Username and password are required" in str(exc_info.value)
+
+
+@pytest.mark.asyncio
+async def test_async_authenticate_oauth_missing_credentials():
+    """Test async authenticate_oauth raises IpsdkError with missing credentials."""
+    mixin = AsyncAuthMixin()
+    mixin.client_id = None
+    mixin.client_secret = None
+    mixin.client = AsyncMock()
+
+    with pytest.raises(exceptions.IpsdkError) as exc_info:
+        await mixin.authenticate_oauth()
+
+    assert "Client ID and client secret are required" in str(exc_info.value)
+
+
 @pytest.mark.asyncio
 async def test_async_authenticate_no_credentials_error():
     """Test async authenticate raises IpsdkError when no credentials provided."""