Merge pull request #33 from adrianno3259/issue32-improve-missing-clan…

…g-format-message

Include error message when clang-format is not found

esss_fix_format/cli.py

@@ -186,7 +186,19 @@ def _process_file(filename, check, format_code):
             changed = b'<replacement ' in output
         else:
             mtime = os.path.getmtime(filename)
-            subprocess.check_output('clang-format -i "%s"' % filename, shell=True)
+
+            # checking if the terminal command is valid
+            # might throw an exception if clang-format is not recognized
+            try:
+                subprocess.check_output('clang-format -i "%s"' % filename, shell=True)
+            except subprocess.CalledProcessError as e:
+                msg = ': ERROR (%s: %s): ' % (type(e).__name__, e)
+                msg += 'Please check if "clang-format" is installed and accessible'
+                error_msg = click.format_filename(filename) + msg
+                click.secho(error_msg, fg='red')
+                errors.append(error_msg)
+                return changed, errors, formatter
+
             changed = os.path.getmtime(filename) != mtime
 
         return changed, errors, formatter

tests/test_esss_fix_format.py

@@ -425,6 +425,42 @@ def test_clang_format(tmpdir, dot_clang_format_to_tmpdir):
     assert obtained == 'int a;'
 
 
+def test_missing_clang_format(tmpdir, mocker, dot_clang_format_to_tmpdir):
+    source = 'int   a;  '
+    filename = tmpdir.join('a.cpp')
+    filename.write(source)
+
+    # Check for invalid format:
+    # File will not pass in the format check
+    check_invalid_file(filename, formatter='clang-format')
+
+    expected_command = 'clang-format -i "main.cpp"'
+    expected_error_code = 1
+
+    # The '*' is used to indicate that there may be a '.' in
+    # the message depending on the python version
+    expected_error_message = "Command '%s' returned non-zero exit status 1*" % expected_command
+    message_extra_details = 'Please check if "clang-format" is installed and accessible'
+
+    mocker.patch.object(
+        subprocess,
+        'check_output',
+        side_effect=subprocess.CalledProcessError(expected_error_code, expected_command))
+
+    # Check if the command-line instruction returned an exception
+    # of type CalledProcessError with the correct error message
+    check_cli_error_output(
+        filename,
+        expected_error_message,
+        message_extra_details,
+        formatter='clang-format'
+    )
+
+    # test should skip file, so no changes are made
+    obtained = filename.read()
+    assert obtained == source
+
+
 def run(args, expected_exit):
     from _pytest.pytester import LineMatcher
     runner = CliRunner()
@@ -453,6 +489,13 @@ def fix_invalid_file(input_file, formatter=None):
     output.fnmatch_lines(str(input_file) + ': Fixed' + _get_formatter_msg(formatter))
 
 
+def check_cli_error_output(input_file, expected_error_message, message_details, formatter=None):
+    output = run([str(input_file)], expected_exit=1)
+    msg = ': ERROR (CalledProcessError: %s): ' % (expected_error_message)
+    msg += message_details
+    output.fnmatch_lines(str(input_file) + msg)
+
+
 def check_invalid_file(input_file, formatter=None):
     output = run(['--check', str(input_file)], expected_exit=1)
     output.fnmatch_lines(str(input_file) + ': Failed' + _get_formatter_msg(formatter))