TST: fix PermissionError on Windows

matplotlib · cgohlke · Oct 20, 2015 · Oct 22, 2015 · Oct 20, 2015 · 4d313ca6ce7dae641dcd2914b016280933f8f7e2
commit 4d313ca6ce7dae641dcd2914b016280933f8f7e2
diff --git a/lib/matplotlib/tests/test_font_manager.py b/lib/matplotlib/tests/test_font_manager.py
@@ -24,6 +24,7 @@ def test_font_priority():
 
 def test_json_serialization():
     with tempfile.NamedTemporaryFile() as temp:
+        temp.close()
         json_dump(fontManager, temp.name)
         copy = json_load(temp.name)
     with warnings.catch_warnings():