Add test coverage

.coveragerc

@@ -0,0 +1,5 @@
+[run]
+omit = tests/*
+
+[html]
+directory = coverage_html_report

.gitignore

@@ -6,4 +6,6 @@ dist
 *.egg*
 README.pdf
 .tox
+coverage_html_report
+.coverage
 docs/source/_build

setup.cfg

@@ -48,6 +48,9 @@ docs =
     Sphinx
     setuptools_scm
     sphinx_rtd_theme
+test =
+    pytest
+    pytest-cov
 
 [flake8]
 format = pylint

tests/test_ansi2html.py

@@ -172,6 +172,22 @@ def test_partial_as_command(
         assert isinstance(expected, str)
         assert expected == html
 
+    @patch("sys.argv", new_callable=lambda: ["ansi2html", "--headers"])
+    @patch("sys.stdout", new_callable=StringIO)
+    def test_headers_as_command(
+        self, mock_stdout: StringIO, mock_argv: List[str]
+    ) -> None:
+
+        main()
+
+        with open(join(_here, "produce_headers.txt"), "rb") as produce_headers:
+            expected = read_to_unicode(produce_headers)
+
+        html = mock_stdout.getvalue()
+
+        assert isinstance(html, str)
+        assert html == "".join(expected)
+
     def test_partial(self) -> None:
         rainbow = "\x1b[1m\x1b[40m\x1b[31mr\x1b[32ma\x1b[33mi\x1b[34mn\x1b[35mb\x1b[36mo\x1b[37mw\x1b[0m\n"
 

tox.ini

@@ -14,9 +14,9 @@ setenv =
 deps =
     mock
     pytest
+    pytest-cov
 sitepackages = False
-commands =
-    pytest
+commands = python -m pytest -ra --cov=ansi2html --no-cov-on-fail --cov-append
 
 [testenv:lint]
 description = Runs all linting tasks