Fix error when wheels already exist in dist/

`build_meta.build_wheel` assumes that the only wheel in its output
directory is the one it builds, but prior to this, it also used the
`dist/` folder as its working output directory. This commit uses a
temporary directory instead, preventing an error that was triggered when
previously-generated wheel files were still sitting in `dist/`.

Fixes GH #1671

1 files changed, 6 insertions, 1 deletions

diff --git a/setuptools/tests/test_build_meta.py b/setuptools/tests/test_build_meta.py
index 90400afc..88e29ffe 100644
--- a/setuptools/tests/test_build_meta.py
+++ b/setuptools/tests/test_build_meta.py
@@ -157,7 +157,6 @@ class TestBuildMetaBackend:
 
         assert os.path.isfile(os.path.join(dist_dir, wheel_name))
 
-    @pytest.mark.xfail(reason="Known error, see GH #1671")
     def test_build_wheel_with_existing_wheel_file_present(self, tmpdir_cwd):
         # Building a wheel should still succeed if there's already a wheel
         # in the wheel directory
@@ -195,6 +194,12 @@ class TestBuildMetaBackend:
         assert os.path.isfile(os.path.join(dist_dir, wheel_one))
         assert wheel_one != wheel_two
 
+        # and if rebuilding the same wheel?
+        open(os.path.join(dist_dir, wheel_two), 'w').close()
+        wheel_three = self.get_build_backend().build_wheel(dist_dir)
+        assert wheel_three == wheel_two
+        assert os.path.getsize(os.path.join(dist_dir, wheel_three)) > 0
+
     def test_build_sdist(self, build_backend):
         dist_dir = os.path.abspath('pip-sdist')
         os.makedirs(dist_dir)