Fix get_blob_path to not make any database calls and add a test

This will be supported by caching, hopefully removing the need to hit the database when the blob object is cached

endpoints/v2/test/test_models_pre_oci.py

@@ -0,0 +1,25 @@
+import hashlib
+
+from playhouse.test_utils import assert_query_count
+
+from data import model
+from data.database import ImageStorageLocation
+from endpoints.v2.models_pre_oci import data_model 
+from test.fixtures import *
+
+def test_get_blob_path(initialized_db):
+  # Add a blob.
+  digest = 'sha256:' + hashlib.sha256("a").hexdigest()
+  location = ImageStorageLocation.get(name='local_us')
+  db_blob = model.blob.store_blob_record_and_temp_link('devtable', 'simple', digest, location, 1,
+                                                       10000000)
+
+  with assert_query_count(1):
+    blob = data_model.get_blob_by_digest('devtable', 'simple', digest)
+    assert blob.uuid == db_blob.uuid
+
+  # The blob tuple should have everything get_blob_path needs, so there should be no queries.
+  with assert_query_count(0):
+    assert data_model.get_blob_path(blob)
+
+  assert data_model.get_blob_path(blob) == model.storage.get_layer_path(db_blob)