Clean up cacher test docs (#728)

* Add cacher to two view estimator

* use two view cacher in configs

* fix punctuation

* add unit test

* add more documentation

* fix formatting

* improve test

* fix test

* add repr method

* fix test

* turn on 2-view cacher

* fix formatting

* add helpful comment

* fix docs

---------

gtsfm/frontend/cacher/global_descriptor_cacher.py

@@ -44,6 +44,7 @@ def __get_cache_path(self, cache_key: str) -> Path:
     def __generate_cache_key(self, image: Image) -> str:
         """Generates the cache key from the input image and underlying global descriptor."""
         input_key = cache_utils.generate_hash_for_image(image)
+        # Concatenate class name and image array hash.
         return "{}_{}".format(self._global_descriptor_obj_cache_key, input_key)
 
     def __load_result_from_cache(self, image: Image) -> Optional[np.ndarray]:
@@ -70,7 +71,7 @@ def describe(self, image: Image) -> np.ndarray:
         details about the output format.
 
         Args:
-            image: the input image.
+            image: The input image.
 
         Returns:
             Global image descriptor, of shape (D,).

tests/frontend/cacher/test_image_matcher_cacher.py

@@ -93,15 +93,16 @@ def test_cache_hit(
         self.assertEqual(computed_keypoints_i1, DUMMY_KEYPOINTS_I1)
         self.assertEqual(computed_keypoints_i2, DUMMY_KEYPOINTS_I2)
 
-        # assert that underlying object was not called
+        # Assert that underlying object was not called.
         underlying_matcher_mock.match.assert_not_called()
 
-        # assert that hash generation was called twice
+        # Assert that hash generation was called twice.
         generate_hash_for_image_mock.assert_called()
 
-        # assert that read function was called once and write function was called once
+        # Assert that read function was called once.
         cache_path = ROOT_PATH / "cache" / "image_matcher" / "mock_matcher_numpy_key_numpy_key.pbz2"
         read_mock.assert_called_once_with(cache_path)
+        # Assert that the write function was not called  (as cache is mocked to already exist).
         write_mock.assert_not_called()
 
 

tests/frontend/cacher/test_matcher_cacher.py

@@ -102,13 +102,15 @@ def test_cache_hit(
         # assert that underlying object was not called
         underlying_matcher_mock.match.assert_not_called()
 
-        # assert that hash generation was called twice
+        # Assert that hash generation was called twice.
         # TODO(ayushbaid): this need proper values
         generate_hash_for_numpy_array_mock.assert_called()
 
-        # assert that read function was called once and write function was called once
+        # Assert that read function was called once
         cache_path = ROOT_PATH / "cache" / "matcher" / "mock_matcher_numpy_key.pbz2"
         read_mock.assert_called_once_with(cache_path)
+
+        # Assert that the write function was not called (as cache is mocked to already exist).
         write_mock.assert_not_called()