add test for producing just headers as command

Signed-off-by: Daniel Ziegenberg <daniel@ziegenberg.at>

tests/test_ansi2html.py

@@ -173,6 +173,22 @@ def test_partial_as_command(
         assert isinstance(expected, str)
         self.assertEqual(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

@@ -3,7 +3,6 @@ minversion = 3.9.0
 envlist =
     lint
     py{36,37,38,39}
-    report
     packaging
 
 isolated_build = True
@@ -17,7 +16,7 @@ deps =
     pytest
     pytest-cov
 sitepackages = False
-commands = python -m pytest -ra --cov=ansi2html --no-cov-on-fail --cov-append --cov-report=
+commands = python -m pytest -ra --cov=ansi2html --no-cov-on-fail --cov-append
 
 [testenv:lint]
 description = Runs all linting tasks
@@ -57,14 +56,6 @@ whitelist_externals =
     rm
     sh
 
-[testenv:report]
-description = Generate test coverage report
-skip_install = true
-deps = coverage
-commands =
-    coverage html
-    coverage report --fail-under=80
-
 [testenv:docs]
 description = Generate Sphinx docs under build/docs
 extras = docs