feat: Add a handwritten tool for Cloud Pub/Sub

Merge https://github.com/google/adk-python/pull/3865

COPYBARA_INTEGRATE_REVIEW=https://github.com/google/adk-python/pull/3865 from kamalaboulhosn:main 37a38a4dcadb04a0af0ec584e6f611204a63cd2a
PiperOrigin-RevId: 845345128

tests/unittests/tools/pubsub/test_pubsub_credentials.py

@@ -0,0 +1,132 @@
+# Copyright 2025 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.
+
+from unittest import mock
+
+from google.adk.tools.pubsub.pubsub_credentials import PUBSUB_DEFAULT_SCOPE
+from google.adk.tools.pubsub.pubsub_credentials import PubSubCredentialsConfig
+from google.auth.credentials import Credentials
+import google.oauth2.credentials
+import pytest
+
+"""Test suite for PubSub credentials configuration validation.
+
+This class tests the credential configuration logic that ensures
+either existing credentials or client ID/secret pairs are provided.
+"""
+
+
+def test_pubsub_credentials_config_client_id_secret():
+  """Test PubSubCredentialsConfig with client_id and client_secret.
+
+  Ensures that when client_id and client_secret are provided, the config
+  object is created with the correct attributes.
+  """
+  config = PubSubCredentialsConfig(client_id="abc", client_secret="def")
+  assert config.client_id == "abc"
+  assert config.client_secret == "def"
+  assert config.scopes == PUBSUB_DEFAULT_SCOPE
+  assert config.credentials is None
+
+
+def test_pubsub_credentials_config_existing_creds():
+  """Test PubSubCredentialsConfig with existing generic credentials.
+
+  Ensures that when a generic Credentials object is provided, it is
+  stored correctly.
+  """
+  mock_creds = mock.create_autospec(Credentials, instance=True)
+  config = PubSubCredentialsConfig(credentials=mock_creds)
+  assert config.credentials == mock_creds
+  assert config.client_id is None
+  assert config.client_secret is None
+
+
+def test_pubsub_credentials_config_oauth2_creds():
+  """Test PubSubCredentialsConfig with existing OAuth2 credentials.
+
+  Ensures that when a google.oauth2.credentials.Credentials object is
+  provided, the client_id, client_secret, and scopes are extracted
+  from the credentials object.
+  """
+  mock_creds = mock.create_autospec(
+      google.oauth2.credentials.Credentials, instance=True
+  )
+  mock_creds.client_id = "oauth_client_id"
+  mock_creds.client_secret = "oauth_client_secret"
+  mock_creds.scopes = ["fake_scope"]
+  config = PubSubCredentialsConfig(credentials=mock_creds)
+  assert config.client_id == "oauth_client_id"
+  assert config.client_secret == "oauth_client_secret"
+  assert config.scopes == ["fake_scope"]
+
+
+@pytest.mark.parametrize(
+    "credentials, client_id, client_secret",
+    [
+        # No arguments provided
+        (None, None, None),
+        # Only client_id is provided
+        (None, "abc", None),
+    ],
+)
+def test_pubsub_credentials_config_validation_errors(
+    credentials, client_id, client_secret
+):
+  """Test PubSubCredentialsConfig validation errors.
+
+  Ensures that ValueError is raised when invalid combinations of credentials
+  and client ID/secret are provided.
+
+  Args:
+    credentials: The credentials object to pass.
+    client_id: The client ID to pass.
+    client_secret: The client secret to pass.
+  """
+  with pytest.raises(
+      ValueError,
+      match=(
+          "Must provide either credentials or client_id and client_secret pair."
+      ),
+  ):
+    PubSubCredentialsConfig(
+        credentials=credentials,
+        client_id=client_id,
+        client_secret=client_secret,
+    )
+
+
+def test_pubsub_credentials_config_both_credentials_and_client_provided():
+  """Test PubSubCredentialsConfig validation errors.
+
+  Ensures that ValueError is raised when invalid combinations of credentials
+  and client ID/secret are provided.
+
+  Args:
+    credentials: The credentials object to pass.
+    client_id: The client ID to pass.
+    client_secret: The client secret to pass.
+  """
+  with pytest.raises(
+      ValueError,
+      match=(
+          "Cannot provide both existing credentials and"
+          " client_id/client_secret/scopes."
+      ),
+  ):
+    PubSubCredentialsConfig(
+        credentials=mock.create_autospec(Credentials, instance=True),
+        client_id="abc",
+        client_secret="def",
+    )