diff --git a/codeguru_profiler_agent/file_reporter/file_reporter.py b/codeguru_profiler_agent/file_reporter/file_reporter.py
index d9c58c0..86a382b 100644
--- a/codeguru_profiler_agent/file_reporter/file_reporter.py
+++ b/codeguru_profiler_agent/file_reporter/file_reporter.py
@@ -35,7 +35,9 @@ def refresh_configuration(self):
         """
         pass
 
-    def report(self, profile, agent_metadata=None, timestamp=datetime.datetime.now()):
+    def report(self, profile, agent_metadata=None, timestamp=None):
+        if timestamp is None:
+            timestamp = datetime.datetime.now()
         output_filename = self._output_filename_for(timestamp)
 
         logger.info("Writing profile to '{}'".format(output_filename))