add core_deps_from_source nox session

Author: parthea

packages/google-api-core/noxfile.py

@@ -32,6 +32,13 @@
 
 DEFAULT_PYTHON_VERSION = "3.14"
 CURRENT_DIRECTORY = pathlib.Path(__file__).parent.absolute()
+UNIT_TEST_STANDARD_DEPENDENCIES = [
+    "mock",
+    "asyncmock",
+    "pytest",
+    "pytest-cov",
+    "pytest-asyncio",
+]
 
 # 'docfx' is excluded since it only needs to run in 'docs-presubmit'
 nox.options.sessions = [
@@ -377,3 +384,69 @@ def docfx(session):
         os.path.join("docs", ""),
         os.path.join("docs", "_build", "html", ""),
     )
+
+@nox.session(python=DEFAULT_PYTHON_VERSION)
+@nox.parametrize(
+    "protobuf_implementation",
+    ["python", "upb"],
+)
+def core_deps_from_source(session, protobuf_implementation):
+    """Run all tests with core dependencies installed from source
+    rather than pulling the dependencies from PyPI.
+    """
+
+    # Install all dependencies
+    session.install("-e", ".")
+
+    # Install dependencies for the unit test environment
+    unit_deps_all = UNIT_TEST_STANDARD_DEPENDENCIES
+    session.install(*unit_deps_all)
+
+    # Because we test minimum dependency versions on the minimum Python
+    # version, the first version we test with in the unit tests sessions has a
+    # constraints file containing all dependencies and extras.
+    with open(
+        CURRENT_DIRECTORY
+        / "testing"
+        / f"constraints-{PYTHON_VERSIONS[0]}.txt",
+        encoding="utf-8",
+    ) as constraints_file:
+        constraints_text = constraints_file.read()
+
+    # Ignore leading whitespace and comment lines.
+    constraints_deps = [
+        match.group(1)
+        for match in re.finditer(
+            r"^\s*(\S+)(?===\S+)", constraints_text, flags=re.MULTILINE
+        )
+    ]
+
+    # Install dependencies specified in `testing/constraints-X.txt`.
+    session.install(*constraints_deps)
+
+    # TODO(https://github.com/googleapis/gapic-generator-python/issues/2358): `grpcio` and
+    # `grpcio-status` should be added to the list below so that they are installed from source,
+    # rather than PyPI.
+    # TODO(https://github.com/googleapis/gapic-generator-python/issues/2357): `protobuf` should be
+    # added to the list below so that it is installed from source, rather than PyPI
+    # Note: If a dependency is added to the `core_dependencies_from_source` list,
+    # the `prerel_deps` list in the `prerelease_deps` nox session should also be updated.
+    core_dependencies_from_source = [
+        f"{CURRENT_DIRECTORY}/../googleapis-common-protos",
+        f"{CURRENT_DIRECTORY}/../google-api-core",
+        "google-auth @ git+https://github.com/googleapis/google-auth-library-python.git",
+        f"{CURRENT_DIRECTORY}/../grpc-google-iam-v1",
+        "proto-plus @ git+https://github.com/googleapis/proto-plus-python.git",
+    ]
+
+    for dep in core_dependencies_from_source:
+        session.install(dep, "--no-deps", "--ignore-installed")
+        print(f"Installed {dep}")
+
+    session.run(
+        "py.test",
+        "tests/unit",
+        env={
+            "PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION": protobuf_implementation,
+        },
+    )