Fix test

categories.py

@@ -165,6 +165,9 @@ def guessHashtagCategory(tagName: str, hashtagCategories: {}) -> str:
     """Tries to guess a category for the given hashtag.
     This works by trying to find the longest similar hashtag
     """
+    if len(tagName) < 4:
+        return ''
+
     categoryMatched = ''
     tagMatchedLen = 0
 
@@ -185,5 +188,5 @@ def guessHashtagCategory(tagName: str, hashtagCategories: {}) -> str:
                 if len(hashtag) > tagMatchedLen:
                     categoryMatched = categoryStr
     if not categoryMatched:
-        return
+        return ''
     return categoryMatched

tests.py

@@ -2843,12 +2843,12 @@ def _testGuessHashtagCategory() -> None:
     print('testGuessHashtagCategory')
     hashtagCategories = {
         "foo": ["swan", "goose"],
-        "bar": ["cat", "mouse"]
+        "bar": ["cats", "mouse"]
     }
     guess = guessHashtagCategory("unspecifiedgoose", hashtagCategories)
     assert guess == "foo"
 
-    guess = guessHashtagCategory("catpic", hashtagCategories)
+    guess = guessHashtagCategory("mastocats", hashtagCategories)
     assert guess == "bar"