diff --git a/arrays_strings/compress/test_compress.py b/arrays_strings/compress/test_compress.py
index 6395f11..a9b9304 100644
--- a/arrays_strings/compress/test_compress.py
+++ b/arrays_strings/compress/test_compress.py
@@ -6,6 +6,7 @@ class TestCompress(object):
     def test_compress(self, func):
         assert_equal(func(None), None)
         assert_equal(func(''), '')
+        assert_equal(func('ABC'), 'ABC')
         assert_equal(func('AABBCC'), 'AABBCC')
         assert_equal(func('AAABCCDDDDE'), 'A3BC2D4E')
         assert_equal(func('BAAACCDDDD'), 'BA3C2D4')
@@ -20,4 +21,4 @@ def main():
 
 
 if __name__ == '__main__':
-    main()
\ No newline at end of file
+    main()