Bug 1604079 - Add a unit test for mozlint yamllint r=ahal

+ some python 3 changes

Differential Revision: https://phabricator.services.mozilla.com/D57263

--HG--
extra : moz-landing-system : lando

tools/lint/test/files/yaml/bad.yml

@@ -0,0 +1,7 @@
+---
+yamllint:
+  description: YAML linteraaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaax
+  include:
+        - .cron.yml
+        - browser/config/
+        - wrong

tools/lint/test/files/yaml/good.yml

@@ -0,0 +1,6 @@
+---
+yamllint:
+    description: YAML linter
+    include:
+        - .cron.yml
+        - browser/config/

tools/lint/test/python.ini

@@ -16,3 +16,4 @@ skip-if = os == "win"
 [test_rst.py]
 [test_codespell.py]
 skip-if = os == "win" || os == "mac"  # codespell installed on Linux
+[test_yaml.py]

tools/lint/test/test_yaml.py

@@ -0,0 +1,26 @@
+import pytest
+import mozunit
+from mozfile import which
+
+LINTER = 'yaml'
+pytestmark = pytest.mark.skipif(not which('yamllint'), reason="yamllint is not installed")
+
+
+def test_basic(lint, paths):
+    results = lint(paths())
+
+    assert len(results) == 2
+
+    assert "line too long (122 > 80 characters)'" in results[0].message
+    assert results[0].level == "error"
+    assert "bad.yml" in results[0].relpath
+    assert results[0].lineno == 3
+
+    assert "wrong indentation: expected 4 but found 8" in results[1].message
+    assert results[1].level == "error"
+    assert "bad.yml" in results[1].relpath
+    assert results[0].lineno == 3
+
+
+if __name__ == '__main__':
+    mozunit.main()

tools/lint/yamllint_/__init__.py

@@ -23,7 +23,7 @@ Try to install it manually with:
     $ pip install -U --require-hashes -r {}
 """.strip().format(YAMLLINT_REQUIREMENTS_PATH)
 
-YAMLLINT_FORMAT_REGEX = re.compile(r'(.*):(.*):(.*): \[(error|warning)\] (.*) \((.*)\)$')
+YAMLLINT_FORMAT_REGEX = re.compile(b'(.*):(.*):(.*): \[(error|warning)\] (.*) \((.*)\)$')
 
 results = []
 
@@ -43,8 +43,8 @@ class YAMLLintProcess(ProcessHandlerMixin):
             print('Unable to match yaml regex against output: {}'.format(line))
             return
 
-        res = {'path': os.path.relpath(abspath, self.config['root']),
-               'message': message,
+        res = {'path': os.path.relpath(str(abspath), self.config['root']),
+               'message': str(message),
                'level': 'error',
                'lineno': line,
                'column': col,