Things DRMacIver does when he's bored of your shit

pypy appears to be unable to realise that the thing that is using a large
amount of memory is worth triggering a GC for because it's not pure
python. Running a GC at each test setup helps keep this under control.

tests/conftest.py

@@ -15,9 +15,11 @@
 
 import warnings
 from tempfile import mkdtemp
+import pytest
 
 from hypothesis import Settings
 from hypothesis.settings import set_hypothesis_home_dir
+import gc
 
 warnings.filterwarnings('error', category=UnicodeWarning)
 
@@ -32,3 +34,8 @@
     resource.setrlimit(resource.RLIMIT_DATA, (MAX_MEMORY, MAX_MEMORY))
 except ImportError:
     pass
+
+
+@pytest.fixture(scope="function", autouse=True)
+def some_fixture():
+    gc.collect()