fix: address flaky tests (#3363)

fix: resolve flaky tests and race conditions in test suite

- Fix telemetry/event tests by patching class methods instead of instances
- Use unique temp files/directories to prevent CI race conditions
- Reset singleton state between tests
- Mock embedchain.Client.setup() to prevent JSON corruption
- Rename test files to test_*.py convention
- Move agent tests to tests/agents directory
- Fix repeated tool usage detection
- Remove database-dependent tools causing initialization errors

tests/agents/test_agent_inject_date.py

@@ -0,0 +1,117 @@
+from datetime import datetime
+from unittest.mock import patch
+
+from crewai.agent import Agent
+from crewai.task import Task
+
+
+def test_agent_inject_date():
+    """Test that the inject_date flag injects the current date into the task.
+
+    Tests that when inject_date=True, the current date is added to the task description.
+    """
+    with patch("datetime.datetime") as mock_datetime:
+        mock_datetime.now.return_value = datetime(2025, 1, 1)
+
+        agent = Agent(
+            role="test_agent",
+            goal="test_goal",
+            backstory="test_backstory",
+            inject_date=True,
+        )
+
+        task = Task(
+            description="Test task",
+            expected_output="Test output",
+            agent=agent,
+        )
+
+        # Store original description
+        original_description = task.description
+
+        agent._inject_date_to_task(task)
+
+        assert "Current Date: 2025-01-01" in task.description
+        assert task.description != original_description
+
+
+def test_agent_without_inject_date():
+    """Test that without inject_date flag, no date is injected.
+
+    Tests that when inject_date=False (default), no date is added to the task description.
+    """
+    agent = Agent(
+        role="test_agent",
+        goal="test_goal",
+        backstory="test_backstory",
+        # inject_date is False by default
+    )
+
+    task = Task(
+        description="Test task",
+        expected_output="Test output",
+        agent=agent,
+    )
+
+    original_description = task.description
+
+    agent._inject_date_to_task(task)
+
+    assert task.description == original_description
+
+
+def test_agent_inject_date_custom_format():
+    """Test that the inject_date flag with custom date_format works correctly.
+
+    Tests that when inject_date=True with a custom date_format, the date is formatted correctly.
+    """
+    with patch("datetime.datetime") as mock_datetime:
+        mock_datetime.now.return_value = datetime(2025, 1, 1)
+
+        agent = Agent(
+            role="test_agent",
+            goal="test_goal",
+            backstory="test_backstory",
+            inject_date=True,
+            date_format="%d/%m/%Y",
+        )
+
+        task = Task(
+            description="Test task",
+            expected_output="Test output",
+            agent=agent,
+        )
+
+        # Store original description
+        original_description = task.description
+
+        agent._inject_date_to_task(task)
+
+        assert "Current Date: 01/01/2025" in task.description
+        assert task.description != original_description
+
+
+def test_agent_inject_date_invalid_format():
+    """Test error handling with invalid date format.
+
+    Tests that when an invalid date_format is provided, the task description remains unchanged.
+    """
+    agent = Agent(
+        role="test_agent",
+        goal="test_goal",
+        backstory="test_backstory",
+        inject_date=True,
+        date_format="invalid",
+    )
+
+    task = Task(
+        description="Test task",
+        expected_output="Test output",
+        agent=agent,
+    )
+
+    original_description = task.description
+
+    agent._inject_date_to_task(task)
+
+    assert task.description == original_description