Use Hypothesis instead of my own janky randomization

3 files changed, 16 insertions, 23 deletions

diff --git a/Makefile b/Makefile
index 6f3edb9b..6dc0cce0 100644
--- a/Makefile
+++ b/Makefile
@@ -26,7 +26,7 @@ clean:
 	-rm -f setuptools-*.egg distribute-*.egg distribute-*.tar.gz
 	-rm -rf doc/_build doc/_spell doc/sample_html_beta
 	-rm -rf .tox_kits
-	-rm -rf .cache .pytest_cache
+	-rm -rf .cache .pytest_cache .hypothesis
 	-rm -rf $$TMPDIR/coverage_test
 
 sterile: clean
diff --git a/requirements/pytest.pip b/requirements/pytest.pip
index b5a4276c..bd3255b1 100644
--- a/requirements/pytest.pip
+++ b/requirements/pytest.pip
@@ -9,6 +9,7 @@ pytest-xdist==1.28.0
 flaky==3.5.3
 mock==3.0.5
 PyContracts==1.8.12
+hypothesis==4.32.1
 
 # Our testing mixins
 unittest-mixins==1.6
diff --git a/tests/test_numbits.py b/tests/test_numbits.py
index b54f65df..2b8e2e4b 100644
--- a/tests/test_numbits.py
+++ b/tests/test_numbits.py
@@ -3,35 +3,27 @@
 
 """Tests for coverage.numbits"""
 
-import random
+from hypothesis import given
+from hypothesis.strategies import sets, integers
 
 from coverage.numbits import nums_to_numbits, numbits_to_nums, merge_numbits
 
 from tests.coveragetest import CoverageTest
 
+# Hypothesis-generated line number data
+line_numbers = sets(integers(min_value=1, max_value=9999), min_size=1)
+
 class NumbitsOpTest(CoverageTest):
     """Tests of the numbits operations in numbits.py."""
 
     run_in_temp_dir = False
 
-    def numbers(self, r):
-        """Produce a list of numbers from a Random object."""
-        return list(set(r.randint(1, 1000) for _ in range(r.randint(100, 200))))
-
-    def test_conversion(self):
-        r = random.Random(1792)
-        for _ in range(10):
-            nums = self.numbers(r)
-            numbits = nums_to_numbits(nums)
-            self.assertEqual(sorted(numbits_to_nums(numbits)), sorted(nums))
-
-    def test_merging(self):
-        r = random.Random(314159)
-        for _ in range(10):
-            nums1 = self.numbers(r)
-            nums2 = self.numbers(r)
-            merged = numbits_to_nums(merge_numbits(nums_to_numbits(nums1), nums_to_numbits(nums2)))
-            all_nums = set()
-            all_nums.update(nums1)
-            all_nums.update(nums2)
-            self.assertEqual(sorted(all_nums), sorted(merged))
+    @given(line_numbers)
+    def test_conversion(self, nums):
+        nums2 = numbits_to_nums(nums_to_numbits(nums))
+        self.assertEqual(nums, set(nums2))
+
+    @given(line_numbers, line_numbers)
+    def test_merging(self, nums1, nums2):
+        merged = numbits_to_nums(merge_numbits(nums_to_numbits(nums1), nums_to_numbits(nums2)))
+        self.assertEqual(nums1 | nums2, set(merged))