fix: COntext manager

Author: tmathern

src/c2pa/c2pa.py

@@ -1560,19 +1560,18 @@ def __del__(self):
         self._cleanup_resources()
 
     def _ensure_valid_state(self):
-        """Ensure the reader is in a valid state for operations.
+        """Ensure the Reader is in a valid state for operations.
 
         Raises:
-            C2paError: If the reader is closed, not initialized, invalid, or
-            has no manifest to read
+            C2paError: If the Reader is closed, not initialized, invalid, or
+            has no manifest to read.
         """
+        # self._no_manifest_to_read is a valid state, albeit an empty one
         if self._closed:
             raise C2paError(Reader._ERROR_MESSAGES['closed_error'])
         if not self._initialized:
             raise C2paError(Reader._ERROR_MESSAGES['not_initialized_error'])
-        if self._no_manifest_to_read:
-            raise C2paError(Reader._ERROR_MESSAGES['no_manifest_error'])
-        if not self._reader:
+        if not self._reader and not self._no_manifest_to_read:
             raise C2paError(Reader._ERROR_MESSAGES['closed_error'])
 
     def _cleanup_resources(self):
@@ -2233,6 +2232,7 @@ class Builder:
         'cleanup_error': "Error during cleanup: {}",
         'builder_cleanup': "Error cleaning up builder: {}",
         'closed_error': "Builder is closed",
+        'not_initialized_error': "Builder is not properly initialized",
         'manifest_error': "Invalid manifest data: must be string or dict",
         'url_error': "Error setting remote URL: {}",
         'resource_error': "Error adding resource: {}",
@@ -2415,7 +2415,7 @@ def _ensure_valid_state(self):
         if self._closed:
             raise C2paError(Builder._ERROR_MESSAGES['closed_error'])
         if not self._initialized:
-            raise C2paError("Builder is not properly initialized")
+            raise C2paError(Builder._ERROR_MESSAGES['not_initialized_error'])
         if not self._builder:
             raise C2paError(Builder._ERROR_MESSAGES['closed_error'])
 

tests/test_unit_tests.py

@@ -85,6 +85,11 @@ def test_get_active_manifest(self):
             expected_label = "contentauth:urn:uuid:c85a2b90-f1a0-4aa4-b17f-f938b475804e"
             self.assertEqual(active_manifest["label"], expected_label)
 
+    def test_get_active_manifest_no_manifest(self):
+        with open(INGREDIENT_TEST_FILE, "rb") as file:
+            reader = Reader("image/jpeg", file)
+            self.assertIsNone(reader.get_active_manifest())
+
     def test_get_manifest_from_label(self):
         with open(self.testPath, "rb") as file:
             reader = Reader("image/jpeg", file)
@@ -98,6 +103,15 @@ def test_get_manifest_from_label(self):
             active_manifest = reader.get_active_manifest()
             self.assertEqual(manifest, active_manifest)
 
+    def test_get_manifest_from_label_no_manifest(self):
+        with open(INGREDIENT_TEST_FILE, "rb") as file:
+            reader = Reader("image/jpeg", file)
+
+            # Test getting manifest by the specific label
+            label = "contentauth:urn:uuid:c85a2b90-f1a0-4aa4-b17f-f938b475804e"
+            manifest = reader.get_manifest_from_label(label)
+            self.assertIsNone(manifest)
+
     def test_stream_get_non_active_manifest_by_label(self):
         video_path = os.path.join(FIXTURES_DIR, "video1.mp4")
         with open(video_path, "rb") as file:
@@ -184,6 +198,11 @@ def test_stream_read_filepath_as_stream_and_parse(self):
             title = manifest_store["manifests"][manifest_store["active_manifest"]]["title"]
             self.assertEqual(title, DEFAULT_TEST_FILE_NAME)
 
+    def test_read_no_manifest_context_manager(self):
+        with Reader("image/jpeg", INGREDIENT_TEST_FILE) as reader:
+            self.assertIsNone(reader.json())
+            self.assertIsNone(reader.get_active_manifest())
+
     def test_reader_double_close(self):
         with open(self.testPath, "rb") as file:
             reader = Reader("image/jpeg", file)