chore(generator): add local google-api-core path override to noxfile showcase tests

Injects local workspace path override for google-api-core package to allow running showcase unit tests successfully when new changes are introduced to api-core.

Author: hebaalazzeh

packages/gapic-generator/noxfile.py

@@ -30,6 +30,8 @@
 from os import path
 import shutil
 
+CURRENT_DIRECTORY = Path(__file__).parent.absolute()
+
 
 nox.options.error_on_missing_interpreters = True
 
@@ -351,6 +353,14 @@ def showcase_library(
             external=True,
         )
 
+        google_api_core_dir = next(
+            (str(p / "packages" / "google-api-core") for p in CURRENT_DIRECTORY.parents if (p / "packages" / "google-api-core").exists()),
+            None
+        )
+        if google_api_core_dir:
+            session.run("pip", "uninstall", "google-api-core", "-y")
+            session.install("-e", google_api_core_dir, "--no-deps")
+
         # Install the generated showcase library.
         if templates == "DEFAULT":
             # Use the constraints file for the specific python runtime version.