Run each test using a temporary directory (#217)

test/08_manylinux2010_only/cibuildwheel_test.py

@@ -9,13 +9,12 @@ def test():
 
     # build the wheels
     # CFLAGS environment veriable is ecessary to fail on 'malloc_info' (on manylinux1) during compilation/linking,
-    # rather than when dynamically loading the Python 
-    utils.cibuildwheel_run(project_dir, add_env={
+    # rather than when dynamically loading the Python
+    actual_wheels = utils.cibuildwheel_run(project_dir, add_env={
         'CIBW_ENVIRONMENT': 'CFLAGS="$CFLAGS -Werror=implicit-function-declaration"',
     })
-    
+
     # also check that we got the right wheels
     expected_wheels = [w for w in utils.expected_wheels('spam', '0.1.0')
                        if not '-manylinux' in w or '-manylinux2010' in w]
-    actual_wheels = os.listdir('wheelhouse')
     assert set(actual_wheels) == set(expected_wheels)