Merge pull request #81 from cisagov/improvement/changes_to_match_deve…

…lopment_preferences

Update to Match Best Practices

src/example/example.py

@@ -35,7 +35,7 @@
 DEFAULT_ECHO_MESSAGE: str = "Hello World from the example default!"
 
 
-def example_div(dividend: float, divisor: float) -> float:
+def example_div(dividend: int, divisor: int) -> float:
     """Print some logging messages."""
     logging.debug("This is a debug message")
     logging.info("This is an info message")
@@ -45,7 +45,7 @@ def example_div(dividend: float, divisor: float) -> float:
     return dividend / divisor
 
 
-def main() -> int:
+def main() -> None:
     """Set up logging and call the example function."""
     args: Dict[str, str] = docopt.docopt(__doc__, version=__version__)
     # Validate and convert arguments as needed
@@ -73,7 +73,7 @@ def main() -> int:
     except SchemaError as err:
         # Exit because one or more of the arguments were invalid
         print(err, file=sys.stderr)
-        return 1
+        sys.exit(1)
 
     # Assign validated arguments to variables
     dividend: int = validated_args["<dividend>"]
@@ -85,24 +85,19 @@ def main() -> int:
         format="%(asctime)-15s %(levelname)s %(message)s", level=log_level.upper()
     )
 
-    logging.info(f"{dividend} / {divisor} == {example_div(dividend, divisor)}")
+    logging.info("%d / %d == %f", dividend, divisor, example_div(dividend, divisor))
 
     # Access some data from an environment variable
     message: str = os.getenv("ECHO_MESSAGE", DEFAULT_ECHO_MESSAGE)
-    logging.info(f'ECHO_MESSAGE="{message}"')
+    logging.info('ECHO_MESSAGE="%s"', message)
 
     # Access some data from our package data (see the setup.py)
     secret_message: str = (
         pkg_resources.resource_string("example", "data/secret.txt")
         .decode("utf-8")
         .strip()
     )
-    logging.info(f'Secret="{secret_message}"')
+    logging.info('Secret="%s"', secret_message)
 
     # Stop logging and clean up
     logging.shutdown()
-    return 0
-
-
-if __name__ == "__main__":
-    sys.exit(main())

tests/test_example.py

@@ -79,21 +79,30 @@ def test_log_levels(level):
             assert (
                 logging.root.hasHandlers() is False
             ), "root logger should not have handlers yet"
-            return_code = example.example.main()
+            return_code = None
+            try:
+                example.example.main()
+            except SystemExit as sys_exit:
+                return_code = sys_exit.code
+            assert return_code is None, "main() should return success"
             assert (
                 logging.root.hasHandlers() is True
             ), "root logger should now have a handler"
             assert (
                 logging.getLevelName(logging.root.getEffectiveLevel()) == level.upper()
             ), f"root logger level should be set to {level.upper()}"
-            assert return_code == 0, "main() should return success (0)"
+            assert return_code is None, "main() should return success"
 
 
 def test_bad_log_level():
     """Validate bad log-level argument returns error."""
     with patch.object(sys, "argv", ["bogus", "--log-level=emergency", "1", "1"]):
-        return_code = example.example.main()
-        assert return_code == 1, "main() should return failure"
+        return_code = None
+        try:
+            example.example.main()
+        except SystemExit as sys_exit:
+            return_code = sys_exit.code
+        assert return_code == 1, "main() should exit with error"
 
 
 @pytest.mark.parametrize("dividend, divisor, quotient", div_params)
@@ -127,5 +136,9 @@ def test_zero_division():
 def test_zero_divisor_argument():
     """Verify that a divisor of zero is handled as expected."""
     with patch.object(sys, "argv", ["bogus", "1", "0"]):
-        return_code = example.example.main()
+        return_code = None
+        try:
+            example.example.main()
+        except SystemExit as sys_exit:
+            return_code = sys_exit.code
         assert return_code == 1, "main() should exit with error"