feat: add app_test cicd workflow (#157)

Co-authored-by: Averi Kitsch <akitsch@google.com>

retrieval_service/app.tests.cloudbuild.yaml

@@ -0,0 +1,37 @@
+# Copyright 2023 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+steps:
+  - id: Install dependencies
+    name: python:3.11
+    dir: retrieval_service
+    entrypoint: pip
+    args:
+      [
+        "install",
+        "-r",
+        "requirements.txt",
+        "-r",
+        "requirements-test.txt",
+        "--user",
+      ]
+
+  - id: Run retrieval service app tests
+    name: python:3.11
+    dir: retrieval_service/app
+    entrypoint: /bin/bash
+    args:
+      - "-c"
+      - |
+        python -m pytest app_test.py