Check for unused translations

Makefile

@@ -39,6 +39,7 @@ check-translations:
 	@-$(foreach lang,$(languages), \
 		msgcmp resources/language/resource.language.$(lang)/strings.po resources/language/resource.language.en_gb/strings.po; \
 	)
+	@tests/check_for_unused_translations.py
 
 check-addon: clean
 	@echo -e "$(white)=$(blue) Starting sanity addon tests$(reset)"

tests/check_for_unused_translations.py

@@ -0,0 +1,28 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+""" Quick and dirty way to check if all translations might be used. """
+
+# pylint: disable=invalid-name,superfluous-parens
+
+import subprocess
+import sys
+
+import polib
+
+error = 0
+
+# Load all python code from git
+code = subprocess.check_output(['git', 'grep', '', '--', 'resources/*.py', 'resources/settings.xml']).decode('utf-8')
+
+# Load po file
+po = polib.pofile('resources/language/resource.language.en_gb/strings.po')
+for entry in po:
+    # Extract msgctxt
+    msgctxt = entry.msgctxt.lstrip('#')
+
+    if msgctxt not in code:
+        print('No usage found for translation:')
+        print(entry)
+        error = 1
+
+sys.exit(error)