Merge pull request #21 from kurtmckee/expand-hypothesis-testing

Expand the hypothesis testing; fix target calculation

tests/test_round_trip.py

@@ -7,7 +7,7 @@
 
 
 lists_of_integers = st.lists(elements=st.integers(min_value=0, max_value=sys.maxsize))
-min_lengths = st.integers(min_value=1, max_value=100)
+min_lengths = st.integers(min_value=0, max_value=255)
 alphabets = st.text(
     alphabet=st.characters(min_codepoint=0, max_codepoint=0x7f),
     min_size=3,
@@ -16,9 +16,12 @@
 
 @given(numbers=lists_of_integers, min_length=min_lengths, alphabet=alphabets)
 def test_round_trip_encoding(numbers, min_length, alphabet):
-    # Encourage hypothesis to find ideal alphabets.
-    target(len(alphabet) / len(set(alphabet)))
-    assume(len(alphabet) == len(set(alphabet)))
+    # Encourage hypothesis to find ideal alphabets
+    # by giving unique alphabets a score of 1.0
+    # and non-unique alphabets a lower score.
+    target(len(set(alphabet)) / len(alphabet))
+    # Reject non-unique alphabets without failing the test.
+    assume(len(set(alphabet)) == len(alphabet))
 
     sqid = sqids.Sqids(min_length=min_length, alphabet=alphabet, blocklist=[])
     assert sqid.decode(sqid.encode(numbers)) == numbers