fix: compute engine id token credentials "with_target_audience" method (#438)

Co-authored-by: Lorenzo Migliorino <50544028+lmiglio@users.noreply.github.com>
Co-authored-by: Bu Sun Kim <8822365+busunkim96@users.noreply.github.com>

1 files changed, 81 insertions, 1 deletions

diff --git a/tests/compute_engine/test_credentials.py b/tests/compute_engine/test_credentials.py
index f05a566..b861984 100644
--- a/tests/compute_engine/test_credentials.py
+++ b/tests/compute_engine/test_credentials.py
@@ -11,17 +11,19 @@
 # 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.
-
+import base64
 import datetime
 
 import mock
 import pytest
+import responses
 
 from google.auth import _helpers
 from google.auth import exceptions
 from google.auth import jwt
 from google.auth import transport
 from google.auth.compute_engine import credentials
+from google.auth.transport import requests
 
 
 class TestCredentials(object):
@@ -270,6 +272,84 @@ class TestIDTokenCredentials(object):
             "target_audience": "https://actually.not",
         }
 
+        # Check that the signer have been initialized with a Request object
+        assert isinstance(self.credentials._signer._request, transport.Request)
+
+    @responses.activate
+    def test_with_target_audience_integration(self):
+        """ Test that it is possible to refresh credentials
+        generated from `with_target_audience`.
+
+        Instead of mocking the methods, the HTTP responses
+        have been mocked.
+        """
+
+        # mock information about credentials
+        responses.add(
+            responses.GET,
+            "http://metadata.google.internal/computeMetadata/v1/instance/"
+            "service-accounts/default/?recursive=true",
+            status=200,
+            content_type="application/json",
+            json={
+                "scopes": "email",
+                "email": "service-account@example.com",
+                "aliases": ["default"],
+            },
+        )
+
+        # mock token for credentials
+        responses.add(
+            responses.GET,
+            "http://metadata.google.internal/computeMetadata/v1/instance/"
+            "service-accounts/service-account@example.com/token",
+            status=200,
+            content_type="application/json",
+            json={
+                "access_token": "some-token",
+                "expires_in": 3210,
+                "token_type": "Bearer",
+            },
+        )
+
+        # mock sign blob endpoint
+        signature = base64.b64encode(b"some-signature").decode("utf-8")
+        responses.add(
+            responses.POST,
+            "https://iam.googleapis.com/v1/projects/-/serviceAccounts/"
+            "service-account@example.com:signBlob?alt=json",
+            status=200,
+            content_type="application/json",
+            json={"keyId": "some-key-id", "signature": signature},
+        )
+
+        id_token = "{}.{}.{}".format(
+            base64.b64encode(b'{"some":"some"}').decode("utf-8"),
+            base64.b64encode(b'{"exp": 3210}').decode("utf-8"),
+            base64.b64encode(b"token").decode("utf-8"),
+        )
+
+        # mock id token endpoint
+        responses.add(
+            responses.POST,
+            "https://www.googleapis.com/oauth2/v4/token",
+            status=200,
+            content_type="application/json",
+            json={"id_token": id_token, "expiry": 3210},
+        )
+
+        self.credentials = credentials.IDTokenCredentials(
+            request=requests.Request(),
+            service_account_email="service-account@example.com",
+            target_audience="https://audience.com",
+        )
+
+        self.credentials = self.credentials.with_target_audience("https://actually.not")
+
+        self.credentials.refresh(requests.Request())
+
+        assert self.credentials.token is not None
+
     @mock.patch(
         "google.auth._helpers.utcnow",
         return_value=datetime.datetime.utcfromtimestamp(0),