style: fix import block formatting with ruff

Co-Authored-By: Joe Moura <joao@crewai.com>

src/crewai/agents/agent_builder/utilities/base_token_process.py

@@ -1,5 +1,9 @@
+import logging
+
 from crewai.types.usage_metrics import UsageMetrics
 
+logger = logging.getLogger(__name__)
+
 
 class TokenProcess:
     def __init__(self) -> None:
@@ -17,7 +21,21 @@ class TokenProcess:
         self.completion_tokens += tokens
         self.total_tokens += tokens
 
-    def sum_cached_prompt_tokens(self, tokens: int) -> None:
+    def sum_cached_prompt_tokens(self, tokens: int | None) -> None:
+        """
+        Adds the given token count to cached prompt tokens.
+        
+        Args:
+            tokens (int | None): Number of tokens to add. None values are ignored.
+            
+        Raises:
+            ValueError: If tokens is negative.
+        """
+        if tokens is None:
+            logger.debug("Received None value for token count")
+            return
+        if tokens < 0:
+            raise ValueError("Token count cannot be negative")
         self.cached_prompt_tokens += tokens
 
     def sum_successful_requests(self, requests: int) -> None:

tests/utilities/test_token_process.py

@@ -0,0 +1,49 @@
+import unittest
+
+from crewai.agents.agent_builder.utilities.base_token_process import TokenProcess
+
+
+class TestTokenProcess(unittest.TestCase):
+    """Test suite for TokenProcess class token counting functionality."""
+
+    def setUp(self):
+        """Initialize a fresh TokenProcess instance before each test."""
+        self.token_process = TokenProcess()
+
+    def test_sum_cached_prompt_tokens_with_none(self):
+        """Test that passing None to sum_cached_prompt_tokens doesn't modify the counter."""
+        initial_tokens = self.token_process.cached_prompt_tokens
+        self.token_process.sum_cached_prompt_tokens(None)
+        self.assertEqual(self.token_process.cached_prompt_tokens, initial_tokens)
+
+    def test_sum_cached_prompt_tokens_with_int(self):
+        """Test that passing an integer correctly increments the counter."""
+        initial_tokens = self.token_process.cached_prompt_tokens
+        self.token_process.sum_cached_prompt_tokens(5)
+        self.assertEqual(self.token_process.cached_prompt_tokens, initial_tokens + 5)
+
+    def test_sum_cached_prompt_tokens_with_zero(self):
+        """Test that passing zero doesn't modify the counter."""
+        initial_tokens = self.token_process.cached_prompt_tokens
+        self.token_process.sum_cached_prompt_tokens(0)
+        self.assertEqual(self.token_process.cached_prompt_tokens, initial_tokens)
+
+    def test_sum_cached_prompt_tokens_with_large_number(self):
+        """Test that the counter works with large numbers."""
+        initial_tokens = self.token_process.cached_prompt_tokens
+        self.token_process.sum_cached_prompt_tokens(1000000)
+        self.assertEqual(self.token_process.cached_prompt_tokens, initial_tokens + 1000000)
+
+    def test_sum_cached_prompt_tokens_multiple_calls(self):
+        """Test that multiple calls accumulate correctly, ignoring None values."""
+        initial_tokens = self.token_process.cached_prompt_tokens
+        self.token_process.sum_cached_prompt_tokens(5)
+        self.token_process.sum_cached_prompt_tokens(None)
+        self.token_process.sum_cached_prompt_tokens(3)
+        self.assertEqual(self.token_process.cached_prompt_tokens, initial_tokens + 8)
+
+    def test_sum_cached_prompt_tokens_with_negative(self):
+        """Test that negative values raise ValueError."""
+        with self.assertRaises(ValueError) as context:
+            self.token_process.sum_cached_prompt_tokens(-1)
+        self.assertEqual(str(context.exception), "Token count cannot be negative")