Add unit test for mixed_line_ending

pre_commit_hooks/mixed_line_ending.py

@@ -74,7 +74,8 @@ def mixed_line_ending(argv=None):
 
     if fix_option == MixedLineEndingOption.NO:
         logging.info('No conversion asked')
-        pass
+
+        return 0
     elif fix_option == MixedLineEndingOption.AUTO:
         for filename in options['filenames']:
             detect_result = _detect_line_ending(filename)
@@ -90,12 +91,18 @@ def mixed_line_ending(argv=None):
                              le_enum.str_print, le_enum.str_print)
 
                 _convert_line_ending(filename, le_enum.string)
+
+                return 1
             elif detect_result == MixedLineDetection.NOT_MIXED:
                 logging.info('The file %s has no mixed line ending', filename)
+
+                return 0
             elif detect_result == MixedLineDetection.UNKNOWN:
                 logging.info('Could not define most frequent line ending in '
                              'file %s. File skiped.', filename)
 
+                return 0
+
     # when a line ending character is forced with --fix option
     else:
         line_ending_enum = fix_option.line_ending_enum
@@ -105,6 +112,8 @@ def mixed_line_ending(argv=None):
         for filename in options['filenames']:
             _convert_line_ending(filename, line_ending_enum.string)
 
+        return 1
+
     return 0
 
 

tests/mixed_line_ending_test.py

@@ -0,0 +1,26 @@
+import pytest
+
+from pre_commit_hooks.mixed_line_ending import mixed_line_ending
+
+# Input, expected return value, expected output
+TESTS_FIX_AUTO = (
+    # only 'LF'
+    (b'foo\nbar\nbaz\n', 0, b'foo\nbar\nbaz\n'),
+    # only 'CRLF'
+    (b'foo\r\nbar\r\nbaz\r\n', 0, b'foo\r\nbar\r\nbaz\r\n'),
+    # mixed with majority of 'LF'
+    (b'foo\r\nbar\nbaz\n', 1, b'foo\nbar\nbaz\n'),
+    # mixed with majority of 'CRLF'
+    (b'foo\r\nbar\nbaz\r\n', 1, b'foo\r\nbar\r\nbaz\r\n'),
+)
+
+
+@pytest.mark.parametrize(('input_s', 'expected_retval', 'output'),
+                         TESTS_FIX_AUTO)
+def test_mixed_line_ending_fix_auto(input_s, expected_retval, output, tmpdir):
+    path = tmpdir.join('file.txt')
+    path.write(input_s)
+    ret = mixed_line_ending(('--fix=auto', '-vv', path.strpath))
+
+    assert ret == expected_retval
+    assert path.read() == output