Fix unit test on VSTS Hosted Linux agents

Author: tleonhardt

tests/test_cmd2.py

@@ -1426,10 +1426,16 @@ def test_help_with_no_docstring(capsys):
 @pytest.mark.skipif(sys.platform.startswith('win'),
                     reason="utils.which function only used on Mac and Linux")
 def test_which_editor_good():
+    import platform
     editor = 'vi'
     path = utils.which(editor)
-    # Assert that the vi editor was found because it should exist on all Mac and Linux systems
-    assert path
+
+    if 'azure' in platform.release().lower():
+        # vi doesn't exist on VSTS Hosted Linux agents
+        assert not path
+    else:
+        # Assert that the vi editor was found because it should exist on all Mac and Linux systems
+        assert path
 
 @pytest.mark.skipif(sys.platform.startswith('win'),
                     reason="utils.which function only used on Mac and Linux")