Add tests for main.

pre_commit/main.py

@@ -70,6 +70,12 @@ def main(argv):
         argv = ['run']
     args = parser.parse_args(argv)
 
+    if args.command == 'help':
+        if args.help_cmd:
+            parser.parse_args([args.help_cmd, '--help'])
+        else:
+            parser.parse_args(['--help'])
+
     runner = Runner.create()
 
     if args.command == 'install':
@@ -82,11 +88,6 @@ def main(argv):
         return autoupdate(runner)
     elif args.command == 'run':
         return run(runner, args)
-    elif args.command == 'help':
-        if args.help_cmd:
-            parser.parse_args([args.help_cmd, '--help'])
-        else:
-            parser.parse_args(['--help'])
     else:
         raise NotImplementedError(
             'Command {0} not implemented.'.format(args.command)

tests/main_test.py

@@ -0,0 +1,143 @@
+from __future__ import absolute_import
+from __future__ import unicode_literals
+
+import argparse
+import mock
+import pytest
+from plumbum import local
+
+from pre_commit import main
+from testing.auto_namedtuple import auto_namedtuple
+
+
+@pytest.yield_fixture
+def mock_commands():
+    with mock.patch.object(main, 'autoupdate') as autoupdate_mock:
+        with mock.patch.object(main, 'clean') as clean_mock:
+            with mock.patch.object(main, 'install') as install_mock:
+                with mock.patch.object(main, 'uninstall') as uninstall_mock:
+                    with mock.patch.object(main, 'run') as run_mock:
+                        yield auto_namedtuple(
+                            autoupdate_mock=autoupdate_mock,
+                            clean_mock=clean_mock,
+                            install_mock=install_mock,
+                            uninstall_mock=uninstall_mock,
+                            run_mock=run_mock,
+                        )
+
+
+class CalledExit(Exception):
+    pass
+
+
+@pytest.yield_fixture
+def argparse_exit_mock():
+    with mock.patch.object(
+        argparse.ArgumentParser, 'exit', side_effect=CalledExit,
+    ) as exit_mock:
+        yield exit_mock
+
+
+@pytest.yield_fixture
+def argparse_parse_args_spy():
+    parse_args_mock = mock.Mock()
+
+    original_parse_args = argparse.ArgumentParser.parse_args
+
+    def fake_parse_args(self, args):
+        # call our spy object
+        parse_args_mock(args)
+        return original_parse_args(self, args)
+
+    with mock.patch.object(
+        argparse.ArgumentParser, 'parse_args', fake_parse_args,
+    ):
+        yield parse_args_mock
+
+
+def assert_only_one_mock_called(mock_objs):
+    total_call_count = sum(mock_obj.call_count for mock_obj in mock_objs)
+    assert total_call_count == 1
+
+
+def test_overall_help(mock_commands, argparse_exit_mock):
+    with pytest.raises(CalledExit):
+        main.main(['--help'])
+
+
+def test_help_command(
+        mock_commands, argparse_exit_mock, argparse_parse_args_spy,
+):
+    with pytest.raises(CalledExit):
+        main.main(['help'])
+
+    argparse_parse_args_spy.assert_has_calls([
+        mock.call(['help']),
+        mock.call(['--help']),
+    ])
+
+
+def test_help_other_command(
+        mock_commands, argparse_exit_mock, argparse_parse_args_spy,
+):
+    with pytest.raises(CalledExit):
+        main.main(['help', 'run'])
+
+    argparse_parse_args_spy.assert_has_calls([
+        mock.call(['help', 'run']),
+        mock.call(['run', '--help']),
+    ])
+
+
+def test_install_command(mock_commands):
+    main.main(['install'])
+    assert mock_commands.install_mock.call_count == 1
+    assert_only_one_mock_called(mock_commands)
+
+
+def test_uninstall_command(mock_commands):
+    main.main(['uninstall'])
+    assert mock_commands.uninstall_mock.call_count == 1
+    assert_only_one_mock_called(mock_commands)
+
+
+def test_clean_command(mock_commands):
+    main.main(['clean'])
+    assert mock_commands.clean_mock.call_count == 1
+    assert_only_one_mock_called(mock_commands)
+
+
+def test_autoupdate_command(mock_commands):
+    main.main(['autoupdate'])
+    assert mock_commands.autoupdate_mock.call_count == 1
+    assert_only_one_mock_called(mock_commands)
+
+
+def test_run_command(mock_commands):
+    main.main(['run'])
+    assert mock_commands.run_mock.call_count == 1
+    assert_only_one_mock_called(mock_commands)
+
+
+def test_no_commands_run_command(mock_commands):
+    main.main([])
+    assert mock_commands.run_mock.call_count == 1
+    assert_only_one_mock_called(mock_commands)
+
+
+def test_help_cmd_in_empty_directory(
+        mock_commands,
+        tmpdir_factory,
+        argparse_exit_mock,
+        argparse_parse_args_spy,
+):
+    path = tmpdir_factory.get()
+
+    with local.cwd(path):
+        with pytest.raises(CalledExit):
+            main.main(['help', 'run'])
+
+    argparse_parse_args_spy.assert_has_calls([
+        mock.call(['help', 'run']),
+        mock.call(['run', '--help']),
+    ])