Improve pytest error tracebacks and fix weakref error in event()

hypothesis-python/RELEASE.rst

@@ -0,0 +1,4 @@
+RELEASE_TYPE: patch
+
+:func:`hypothesis.event` now works for hashable objects which do not
+support weakrefs, such as integers and tuples.

hypothesis-python/src/_hypothesis_pytestplugin.py

@@ -180,6 +180,7 @@ def pytest_configure(config):
 
     @pytest.hookimpl(hookwrapper=True)
     def pytest_runtest_call(item):
+        __tracebackhide__ = True
         if not (hasattr(item, "obj") and "hypothesis" in sys.modules):
             yield
             return
@@ -192,10 +193,14 @@ def pytest_runtest_call(item):
         if not is_hypothesis_test(item.obj):
             # If @given was not applied, check whether other hypothesis
             # decorators were applied, and raise an error if they were.
+            # We add this frame of indirection to enable __tracebackhide__.
+            def raise_hypothesis_usage_error(msg):
+                raise InvalidArgument(msg)
+
             if getattr(item.obj, "is_hypothesis_strategy_function", False):
                 from hypothesis.errors import InvalidArgument
 
-                raise InvalidArgument(
+                raise_hypothesis_usage_error(
                     f"{item.nodeid} is a function that returns a Hypothesis strategy, "
                     "but pytest has collected it as a test function.  This is useless "
                     "as the function body will never be executed.  To define a test "
@@ -211,7 +216,7 @@ def pytest_runtest_call(item):
                 if hasattr(item.obj, attribute):
                     from hypothesis.errors import InvalidArgument
 
-                    raise InvalidArgument(message % (name,))
+                    raise_hypothesis_usage_error(message % (name,))
             yield
         else:
             from hypothesis import HealthCheck, settings

hypothesis-python/src/hypothesis/internal/conjecture/engine.py

@@ -1067,10 +1067,13 @@ def event_to_string(self, event):
             return event
         try:
             return self.events_to_strings[event]
-        except KeyError:
+        except (KeyError, TypeError):
             pass
         result = str(event)
-        self.events_to_strings[event] = result
+        try:
+            self.events_to_strings[event] = result
+        except TypeError:
+            pass
         return result
 
 

hypothesis-python/tests/conjecture/test_engine.py

@@ -1587,3 +1587,8 @@ def test(data):
             runner.cached_test_function([c])
 
         assert runner.tree.is_exhausted
+
+
+def test_can_convert_non_weakref_types_to_event_strings():
+    runner = ConjectureRunner(lambda data: None)
+    runner.event_to_string(())

hypothesis-python/tests/cover/test_statistical_events.py

@@ -254,3 +254,8 @@ def test(value):
     stats = describe_statistics(call_for_statistics(test))
     assert "- Events:" in stats
     assert "- Highest target score: " in stats
+
+
+@given(st.booleans())
+def test_event_with_non_weakrefable_keys(b):
+    event((b,))

hypothesis-python/tests/pytest/test_checks.py

@@ -33,4 +33,6 @@ def test_repro_without_given_fails():
 
 def test_decorators_without_given_should_fail(testdir):
     script = testdir.makepyfile(TEST_DECORATORS_ALONE)
-    testdir.runpytest(script).assert_outcomes(failed=4)
+    result = testdir.runpytest(script)
+    result.assert_outcomes(failed=4)
+    assert "pytest_runtest_call" not in "\n".join(result.outlines)