Fix silly tests looking for specific strings...

tests/test_har2locust.py

@@ -104,7 +104,7 @@ def test_plugins():
     assert proc.returncode == 0, f"Bad return code {proc.returncode}, stderr: {stderr}"
     print(stderr)  # this will only be shown if it fails anyway
     assert stdout == expected_output
-    assert "self.reader.user" in stdout
+    assert "next(" in stdout
     assert "self.customer" in stdout
     # test url timestamp rewriting function
     assert "self.rest_" in stdout
@@ -145,7 +145,7 @@ def test_plugins_run_as_module():  # same as above test, but run as module
     stdout, stderr = proc.communicate()
     assert proc.returncode == 0, f"Bad return code {proc.returncode}, stderr: {stderr}"
     assert stdout == expected_output
-    assert "self.reader.user" in stdout
+    assert "next(" in stdout
     assert "self.customer" in stdout
     # test url timestamp rewriting function
     assert "self.rest_" in stdout