servo: Merge #12781 - Improve tidy's license validation logic (from UK992:tidycheck-rebased); r=Wafflespeanut

Rebased and fixed https://github.com/servo/servo/pull/10721, which is inactive for months.
Fixes https://github.com/servo/servo/issues/10716

r? @larsbergstrom or @edunham

Source-Repo: https://github.com/servo/servo
Source-Revision: 8419f96dc0cb79c83922b62166390f6688f2aae0

servo/python/tidy/servo_tidy_tests/apache2_license.rs

@@ -0,0 +1,5 @@
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.

servo/python/tidy/servo_tidy_tests/shebang_license.py

@@ -0,0 +1,4 @@
+#!/usr/bin/env python
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.

servo/python/tidy/servo_tidy_tests/test_tidy.py

@@ -48,6 +48,11 @@ class CheckTidiness(unittest.TestCase):
         self.assertEqual('incorrect license', errors.next()[2])
         self.assertNoMoreErrors(errors)
 
+    def test_shebang_license(self):
+        errors = tidy.collect_errors_for_files(iterFile('shebang_license.py'), [], [tidy.check_license], print_text=False)
+        self.assertEqual('missing blank line after shebang', errors.next()[2])
+        self.assertNoMoreErrors(errors)
+
     def test_shell(self):
         errors = tidy.collect_errors_for_files(iterFile('shell_tidy.sh'), [], [tidy.check_shell], print_text=False)
         self.assertEqual('script does not have shebang "#!/usr/bin/env bash"', errors.next()[2])
@@ -58,6 +63,10 @@ class CheckTidiness(unittest.TestCase):
         self.assertEqual('script should use `[[` instead of `[` for conditional testing', errors.next()[2])
         self.assertNoMoreErrors(errors)
 
+    def test_apache2_incomplete(self):
+        errors = tidy.collect_errors_for_files(iterFile('apache2_license.rs'), [], [tidy.check_license])
+        self.assertEqual('incorrect license', errors.next()[2])
+
     def test_rust(self):
         errors = tidy.collect_errors_for_files(iterFile('rust_tidy.rs'), [], [tidy.check_rust], print_text=False)
         self.assertEqual('use statement spans multiple lines', errors.next()[2])