diff --git a/github_tests_validator_app/constants.py b/github_tests_validator_app/constants.py
index 8bd192d..61130d4 100644
--- a/github_tests_validator_app/constants.py
+++ b/github_tests_validator_app/constants.py
@@ -1,4 +1,10 @@
+from typing import cast
+
 import os
 
-APP_ID = os.getenv("GH_APP_ID")
-APP_KEY = os.getenv("GH_APP_KEY")
+APP_ID = cast(str, os.getenv("GH_APP_ID"))
+APP_KEY = cast(str, os.getenv("GH_APP_KEY"))
+SOLUTION_TESTS_ACCESS_TOKEN = cast(str, os.getenv("SOLUTION_TESTS_ACCESS_TOKEN"))
+SOLUTION_OWNER = "artefactory-fr"
+SOLUTION_REPO_NAME = "school_of_data_tests"
+TESTS_FOLDER_NAME = "tests"
diff --git a/github_tests_validator_app/utils.py b/github_tests_validator_app/utils.py
index 18b93f7..949b81b 100644
--- a/github_tests_validator_app/utils.py
+++ b/github_tests_validator_app/utils.py
@@ -1,10 +1,63 @@
+from typing import Any, List
+
 import hashlib
 
+from github import ContentFile, Github, Repository
+from github_tests_validator_app.constants import TESTS_FOLDER_NAME
+
 
-def get_hash_files(contents):
+def get_hash_files(contents: List[ContentFile.ContentFile]) -> str:
     hash_sum = ""
     for content in contents:
         hash_sum += content.sha
     hash = hashlib.sha256()
     hash.update(hash_sum.encode())
     return str(hash.hexdigest())
+
+
+def get_tests_hash(repo: Repository.Repository) -> str:
+    contents = repo.get_contents(TESTS_FOLDER_NAME)
+    files_content = get_files_content(contents, repo)
+    hash = get_hash_files(files_content)
+    return hash
+
+
+def get_files_content(contents: Any, repo: Repository.Repository) -> List[ContentFile.ContentFile]:
+    files_content = []
+    while contents:
+        file_content = contents.pop(0)
+        if file_content.type == "dir":
+            contents.extend(repo.get_contents(file_content.path))
+        else:
+            files_content.append(file_content)
+    return files_content
+
+
+def get_repo(token: str, owner: str, repo_name: str) -> Repository.Repository:
+    git_connection = Github(login_or_token=token)
+    repo = git_connection.get_repo(f"{owner}/{repo_name}")
+    return repo
+
+
+def get_last_hash_commit(repo: Repository.Repository, branch_name: str) -> str:
+    branch = repo.get_branch(branch_name)
+    return branch.commit.sha
+
+
+def compare_tests_folder(
+    student_repo: Repository.Repository, solution_repo: Repository.Repository
+) -> bool:
+    student_contents = student_repo.get_contents(TESTS_FOLDER_NAME)
+
+    if (
+        isinstance(student_contents, ContentFile.ContentFile)
+        and student_contents.type == "submodule"
+    ):
+        solution_last_commit = get_last_hash_commit(solution_repo, "main")
+        student_tests_commit = student_contents.sha
+        return solution_last_commit == student_tests_commit
+
+    student_hash_tests = get_tests_hash(student_repo)
+    solution_hash_tests = get_tests_hash(solution_repo)
+
+    return student_hash_tests == solution_hash_tests
diff --git a/server.py b/server.py
index 1c199ef..59c30ea 100644
--- a/server.py
+++ b/server.py
@@ -1,8 +1,15 @@
 import uvicorn
 from fastapi import FastAPI, Request
-from github import Github, GithubIntegration
-from github_tests_validator_app.constants import APP_ID, APP_KEY
-from github_tests_validator_app.utils import get_hash_files
+from github import GithubIntegration
+from github_tests_validator_app.constants import (
+    APP_ID,
+    APP_KEY,
+    SOLUTION_OWNER,
+    SOLUTION_REPO_NAME,
+    SOLUTION_TESTS_ACCESS_TOKEN,
+    TESTS_FOLDER_NAME,
+)
+from github_tests_validator_app.utils import compare_tests_folder, get_repo
 
 app = FastAPI()
 
@@ -21,17 +28,16 @@ async def main(request: Request) -> None:
 
     owner = payload["repository"]["owner"]["login"]
     repo_name = payload["repository"]["name"]
+    token = git_integration.get_access_token(
+        git_integration.get_installation(owner, repo_name).id
+    ).token
+
+    student_repo = get_repo(token, owner, repo_name)
+    solution_repo = get_repo(SOLUTION_TESTS_ACCESS_TOKEN, SOLUTION_OWNER, SOLUTION_REPO_NAME)
 
-    git_connection = Github(
-        login_or_token=git_integration.get_access_token(
-            git_integration.get_installation(owner, repo_name).id
-        ).token
-    )
+    tests_havent_changed = compare_tests_folder(student_repo, solution_repo)
+    print(tests_havent_changed)
 
-    repo = git_connection.get_repo(f"{owner}/{repo_name}")
-    contents = repo.get_contents("tests")
-    hashes = get_hash_files(contents)
-    print(hashes)
     return
 
 
diff --git a/tests/units/basic_test.py b/tests/units/basic_test.py
index 8ff336f..f8dbcf1 100644
--- a/tests/units/basic_test.py
+++ b/tests/units/basic_test.py
@@ -2,4 +2,4 @@
 
 
 def test_length_hash():
-    assert len(get_hash_files("")) == 64
+    assert len(get_hash_files([])) == 64