Enable mypy (#26)

* enable mypy

* unittests for parse_arguments

Author: nkr0

README.rst

@@ -59,7 +59,9 @@ Unreleased
 
 - Support Python 3.12
 - Include error info from multiple locations
-- Added ``junitparser`` as a dependency to write junit output.
+- Added ``junitparser`` as a dependency to write junit output
+- Update unitests for argument parser
+- Enable mypy for type checking
 
 2.3.0 - 2023-04-30
 ^^^^^^^^^^^^^^^^^^

cppcheck_junit.py

@@ -49,7 +49,7 @@ class CppcheckError:
     verbose: str
 
 
-def parse_arguments() -> argparse.Namespace:
+def parse_arguments(args: List[str]) -> argparse.Namespace:
     parser = argparse.ArgumentParser(
         description="Converts Cppcheck XML version 2 to JUnit XML format.\n"
         "Usage:\n"
@@ -63,11 +63,11 @@ def parse_arguments() -> argparse.Namespace:
         "error_exitcode",
         type=int,
         nargs="?",
-        const=0,
+        default=ExitStatus.success,
         help="If errors are found, "
         f"integer <n> is returned instead of default {ExitStatus.success}.",
     )
-    return parser.parse_args()
+    return parser.parse_args(args)
 
 
 def parse_cppcheck(file_name: str) -> Dict[str, List[CppcheckError]]:
@@ -86,36 +86,36 @@ def parse_cppcheck(file_name: str) -> Dict[str, List[CppcheckError]]:
     """
     root: ElementTree.Element = ElementTree.parse(file_name).getroot()
 
-    if root.get("version") is None or int(root.get("version")) != 2:
+    if int(root.get("version", "0")) != 2:
         raise ValueError("Parser only supports Cppcheck XML version 2.  Use --xml-version=2.")
 
     error_root = root.find("errors")
-
     errors = collections.defaultdict(list)
-    for error_element in error_root:
-        file = error_element.get("file0", "")
-        locations = []
-        for location in error_element.findall("location"):
-            if not file:
-                file = location.get("file", "")
-            locations.append(
-                CppcheckLocation(
-                    location.get("file", ""),
-                    int(location.get("line", 0)),
-                    int(location.get("column", 0)),
-                    location.get("info", ""),
+    if error_root is not None:
+        for error_element in error_root:
+            file = error_element.get("file0", "")
+            locations = []
+            for location in error_element.findall("location"):
+                if not file:
+                    file = location.get("file", "")
+                locations.append(
+                    CppcheckLocation(
+                        location.get("file", ""),
+                        int(location.get("line", 0)),
+                        int(location.get("column", 0)),
+                        location.get("info", ""),
+                    )
                 )
-            )
 
-        error = CppcheckError(
-            file=file,
-            locations=locations,
-            message=error_element.get("msg", ""),
-            severity=error_element.get("severity", ""),
-            error_id=error_element.get("id", ""),
-            verbose=error_element.get("verbose", ""),
-        )
-        errors[error.file].append(error)
+            error = CppcheckError(
+                file=file,
+                locations=locations,
+                message=error_element.get("msg", ""),
+                severity=error_element.get("severity", ""),
+                error_id=error_element.get("id", ""),
+                verbose=error_element.get("verbose", ""),
+            )
+            errors[error.file].append(error)
 
     return errors
 
@@ -187,13 +187,13 @@ def generate_test_suite(errors: Dict[str, List[CppcheckError]]) -> TestSuite:
     return test_suite
 
 
-def main() -> ExitStatus:  # pragma: no cover
+def main() -> int:  # pragma: no cover
     """Main function.
 
     Returns:
         Exit code.
     """
-    args = parse_arguments()
+    args = parse_arguments(sys.argv[1:])
 
     try:
         errors = parse_cppcheck(args.input_file)
@@ -210,7 +210,7 @@ def main() -> ExitStatus:  # pragma: no cover
     tree = JUnitXml("Cppcheck")
     tree.add_testsuite(generate_test_suite(errors))
     tree.write(args.output_file)
-    return args.error_exitcode if len(errors) > 0 else ExitStatus.success
+    return int(args.error_exitcode) if len(errors) > 0 else ExitStatus.success
 
 
 if __name__ == "__main__":  # pragma: no cover

pyproject.toml

@@ -5,6 +5,10 @@ build-backend = "setuptools.build_meta"
 [tool.mypy]
 ignore_missing_imports = true
 strict = true
+untyped_calls_exclude = "junitparser"
+[[tool.mypy.overrides]]
+module = "junitparser"
+implicit_reexport = true
 
 [tool.black]
 line-length = 99

test.py

@@ -5,10 +5,11 @@
 from __future__ import absolute_import, division, print_function, unicode_literals
 
 from copy import deepcopy
-import sys
 import unittest
 from xml.etree import ElementTree
 
+from exitstatus import ExitStatus
+
 from cppcheck_junit import (
     CppcheckError,
     CppcheckLocation,
@@ -102,6 +103,10 @@ def test_malformed(self) -> None:
         with self.assertRaises(ElementTree.ParseError):
             parse_cppcheck("tests/cppcheck-out-malformed.xml")
 
+    def test_malformed_no_errors(self) -> None:
+        errors = parse_cppcheck("tests/cppcheck-malformed-no-errors.xml")
+        self.assertEqual(errors, {})
+
 
 class GenerateTestError(unittest.TestCase):
     basic_error = CppcheckError("file", [], "message", "severity", "error_id", "verbose")
@@ -189,12 +194,26 @@ def test_multiple(self) -> None:
 
 
 class ParseArgumentsTestCase(unittest.TestCase):
-    def test_no_arguments(self) -> None:
+    def test_empty(self) -> None:
+        with self.assertRaises(SystemExit):
+            parse_arguments([])
+
+    def test_one_arg(self) -> None:
         with self.assertRaises(SystemExit):
-            # Suppress argparse stderr.
-            class NullWriter:
-                def write(self, s: str) -> None:
-                    pass
+            parse_arguments(["h"])
+
+    def test_two_args(self) -> None:
+        args = parse_arguments(["input", "output"])
+        self.assertEqual(args.input_file, "input")
+        self.assertEqual(args.output_file, "output")
+        self.assertEqual(args.error_exitcode, ExitStatus.success)
 
-            sys.stderr = NullWriter()
-            parse_arguments()
+    def test_three_args(self) -> None:
+        args = parse_arguments(["input", "output", "1"])
+        self.assertEqual(args.input_file, "input")
+        self.assertEqual(args.output_file, "output")
+        self.assertEqual(args.error_exitcode, 1)
+
+    def test_invalid_exitcode(self) -> None:
+        with self.assertRaises(SystemExit):
+            parse_arguments(["input", "output", "a"])

tests/cppcheck-malformed-no-errors.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<results version="2">
+    <cppcheck version="1.71"/>
+</results>

tox.ini

@@ -7,7 +7,7 @@ extend-exclude =
 [gh-actions]
 python =
     3.8: py38
-    3.9: py39, fmt-check, lint
+    3.9: py39, fmt-check, lint, type-check
     3.10: py310
     3.11: py311
     3.12: py312
@@ -29,7 +29,6 @@ deps =
 commands =
     python -m pytest --cov=./ --cov-report=html --cov-report=term --cov-fail-under=100 test.py
 
-# TODO: Get mypy checking to pass.
 [testenv:type-check]
 skip_install = true
 deps =
@@ -58,7 +57,7 @@ skip_install = true
 deps =
     -r{toxinidir}/dev-requirements.txt
 commands =
-    isort --check .
+    isort --check -v .
     black --check .
 
 [testenv:build]