Fix tests

src/darker/tests/test_command_line.py

@@ -15,6 +15,7 @@
 from darker import black_diff
 from darker.__main__ import main
 from darker.command_line import make_argument_parser, parse_command_line
+from darker.config import ConfigurationError
 from darker.git import RevisionRange
 from darker.tests.helpers import filter_dict, isort_present, raises_if_exception
 from darker.utils import TextDocument, joinlines
@@ -132,16 +133,16 @@ def test_parse_command_line_config_src(
         expect_modified=("stdout", ...),
     ),
     dict(
-        argv=["--stdout", "."],
+        argv=["--stdout", "dummy.py"],
         expect_value=("stdout", True),
         expect_config=("stdout", True),
         expect_modified=("stdout", True),
     ),
     dict(
-        argv=["--diff", "--stdout", "."],
-        expect_value=("stdout", True),
-        expect_config=("stdout", True),
-        expect_modified=("stdout", True),
+        argv=["--diff", "--stdout", "dummy.py"],
+        expect_value=ConfigurationError,
+        expect_config=ConfigurationError,
+        expect_modified=ConfigurationError,
     ),
     dict(
         argv=["."],
@@ -289,26 +290,32 @@ def test_parse_command_line_config_src(
     ),
 )
 def test_parse_command_line(
-    tmpdir, monkeypatch, argv, expect_value, expect_config, expect_modified
+    tmp_path, monkeypatch, argv, expect_value, expect_config, expect_modified
 ):
     """``parse_command_line()`` parses options correctly"""
-    monkeypatch.chdir(tmpdir)
-    args, effective_cfg, modified_cfg = parse_command_line(argv)
+    monkeypatch.chdir(tmp_path)
+    (tmp_path / "dummy.py").touch()
 
-    arg_name, expect_arg_value = expect_value
-    assert getattr(args, arg_name) == expect_arg_value
+    with raises_if_exception(expect_value):
 
-    option, expect_config_value = expect_config
-    if expect_config_value is ...:
-        assert option not in effective_cfg
-    else:
-        assert effective_cfg[option] == expect_config_value  # type: ignore
+        args, effective_cfg, modified_cfg = parse_command_line(argv)
 
-    modified_option, expect_modified_value = expect_modified
-    if expect_modified_value is ...:
-        assert modified_option not in modified_cfg
-    else:
-        assert modified_cfg[modified_option] == expect_modified_value  # type: ignore
+        arg_name, expect_arg_value = expect_value
+        assert getattr(args, arg_name) == expect_arg_value
+
+        option, expect_config_value = expect_config
+        if expect_config_value is ...:
+            assert option not in effective_cfg
+        else:
+            assert effective_cfg[option] == expect_config_value  # type: ignore
+
+        modified_option, expect_modified_value = expect_modified
+        if expect_modified_value is ...:
+            assert modified_option not in modified_cfg
+        else:
+            assert (
+                modified_cfg[modified_option] == expect_modified_value  # type: ignore
+            )
 
 
 def test_help_description_without_isort_package(capsys):
@@ -543,7 +550,7 @@ def test_options(git_repo, options, expect):
         retval = main(options)
 
     expect = (Path(git_repo.root), expect[1]) + expect[2:]
-    format_edited_parts.assert_called_once_with(*expect)
+    format_edited_parts.assert_called_once_with(*expect, report_unmodified=False)
     assert retval == 0
 
 

src/darker/tests/test_config.py

@@ -79,6 +79,7 @@ def test_replace_log_level_name(log_level, expect):
     dict(diff=True, stdout=True, expect=ConfigurationError),
 )
 def test_output_mode_validate_diff_stdout(diff, stdout, expect):
+    """Validation fails only if ``--diff`` and ``--stdout`` are both enabled"""
     with raises_if_exception(expect):
         OutputMode.validate_diff_stdout(diff, stdout)
 
@@ -100,6 +101,7 @@ def test_output_mode_validate_diff_stdout(diff, stdout, expect):
     dict(stdout=True, src=["directory"], expect=ConfigurationError),
 )
 def test_output_mode_validate_stdout_src(tmp_path, monkeypatch, stdout, expect, src):
+    """Validation fails only if exactly one file isn't provided for ``--stdout``"""
     monkeypatch.chdir(tmp_path)
     Path("first.py").touch()
     Path("second.py").touch()
@@ -115,6 +117,7 @@ def test_output_mode_validate_stdout_src(tmp_path, monkeypatch, stdout, expect,
     dict(diff=True, stdout=True, expect=ConfigurationError),
 )
 def test_output_mode_from_args(diff, stdout, expect):
+    """Correct output mode results from the ``--diff`` and ``stdout`` options"""
     args = Namespace()
     args.diff = diff
     args.stdout = stdout