Fix dangling file handles

Summary: Not sure why these weren't closed properly before

Differential Revision: D33961678

fbshipit-source-id: d110cc971adc2f2fc9744fb48fa474862fd10e6b

plugin/src/py/android_screenshot_tests/pull_screenshots.py

@@ -113,7 +113,8 @@ def generate_html(
     #   and returns a url to an image from a previous run of the test,
     # old_imgs_data a dict that will be used in the test_img_api url.
     # Creates the html for showing a before and after comparison of the images.
-    screenshots = json.load(open(join(output_dir, "metadata.json")))
+    with open(join(output_dir, "metadata.json")) as m:
+        screenshots = json.load(m)
     alternate = False
     index_html = abspath(join(output_dir, "index.html"))
     with codecs.open(index_html, mode="w", encoding="utf-8") as html:
@@ -530,7 +531,8 @@ def move_all_files_to_different_directory(source_dir, target_dir):
 
 
 def _summary(dir):
-    metadataJson = json.load(open(join(dir, "metadata.json")))
+    with open(join(dir, "metadata.json")) as f:
+        metadataJson = json.load(f)
     count = len(metadataJson)
     print("Found %d screenshots" % count)
 

plugin/src/py/android_screenshot_tests/recorder.py

@@ -71,8 +71,8 @@ def _copy(self, name, w, h):
         im.close()
 
     def _get_metadata_json(self):
-        file = open(join(self._input, "metadata.json"), "r")
-        return json.load(file)
+        with open(join(self._input, "metadata.json"), "r") as f:
+            return json.load(f)
 
     def _record(self):
         metadata = self._get_metadata_json()