fixup! Add test for working and broken symlinks

Author: matthijskooijman

Diff for: test/test_compile.py

@@ -178,19 +178,27 @@ def test_compile_with_symlink(run_command, data_dir):
 
     # create a symlink to some external file and move the main .ino
     # contents into that to check that the symlink is actually compiled
-    with tempfile.NamedTemporaryFile() as external:
-        os.symlink(external.name, symlink_file)
-
-        with open(main_file, mode="rb+") as main:
-            external.write(main.read())
-            external.flush()
-            main.truncate(0)
-            main.flush()
-
-        # Build sketch for arduino:avr:uno
-        result = run_command(["compile", "-b", fqbn, sketch_path])
-        assert result.stderr == ""
-        assert result.ok
+    with tempfile.NamedTemporaryFile(delete=False) as external:
+        try:
+            os.symlink(external.name, symlink_file)
+
+            with open(main_file, mode="rb+") as main:
+                external.write(main.read())
+                external.flush()
+                main.truncate(0)
+                main.flush()
+
+            # Close to allow re-opening the file on Windows
+            # See https://bugs.python.org/issue14243
+            external.close()
+
+            # Build sketch for arduino:avr:uno
+            result = run_command(["compile", "-b", fqbn, sketch_path])
+            assert result.stderr == ""
+            assert result.ok
+        finally:
+            # Explicit cleanup needed because the file is closed above
+            os.unlink(external.name)
 
     def test_broken_symlink(sketch_name, link_name, target_name, expect_error):
         sketch_path = os.path.join(data_dir, sketch_name)