Update tests/fixtures.py

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

Author: ahoblitz

tests/fixtures.py

@@ -66,14 +66,15 @@ def completed_task(task_builder):
 
 
 @pytest.fixture
-def task_with_history(task_builder, message_builder):
+def task_with_history(task_builder):
     messages = [
-        message_builder.as_user().with_text('Hello').build(),
-        message_builder.as_agent().with_text('Hi there!').build(),
+        MessageBuilder().as_user().with_text('Hello').build(),
+        MessageBuilder().as_agent().with_text('Hi there!').build(),
     ]
     return task_builder.with_history(*messages).build()
 
 
+
 @pytest.fixture
 def task_with_artifacts(task_builder, artifact_builder):
     artifacts = [