fix escaping of the & (helping #2)

escape_amp.py

@@ -0,0 +1,38 @@
+# -*- encoding: utf-8 -*-
+
+import re
+
+__all__ = [
+    'escape_amp'
+]
+
+RE_REPLACE_AMPERSAND = re.compile(r'&(\w*)(;)?')
+
+def replace(matchobj):
+    if matchobj.group(2):
+        return matchobj.group(0)
+    else:
+        return matchobj.group(0).replace('&', '&')
+
+def escape_amp(text):
+    return RE_REPLACE_AMPERSAND.sub(replace, text)
+
+def run_tests():
+    tests = [
+        ['&', '&'],
+        ['&amp', '&amp'],
+        ['&', '&'],
+        ['& &hello &bonjour;', '& &hello &bonjour;']
+    ]
+    fails = 0
+    for i, (subject, result) in enumerate(tests):
+        if RE_REPLACE_AMPERSAND.sub(replace, subject) != result:
+            print('TEST FAIL ({i}): {subject!r} escaped did not match {result!r}'.format(**locals()))
+            fails += 1
+    if fails == 0:
+        print("SUCCESS: every tests ({}) passed successfully!".format(len(tests)))
+    else:
+        print("{} test{} failed".format(fails, 's' if fails > 1 else ''))
+
+if __name__ == '__main__':
+    run_tests()