Revert "feat: workload identity federation support (#686)" (#691)

This reverts commit 5dcd2b1bdd9d21522636d959cffc49ee29dda88f.
diff --git a/tests/test__default.py b/tests/test__default.py
index ef6cb78..74511f9 100644
--- a/tests/test__default.py
+++ b/tests/test__default.py
@@ -20,13 +20,10 @@
 
 from google.auth import _default
 from google.auth import app_engine
-from google.auth import aws
 from google.auth import compute_engine
 from google.auth import credentials
 from google.auth import environment_vars
 from google.auth import exceptions
-from google.auth import external_account
-from google.auth import identity_pool
 from google.oauth2 import service_account
 import google.oauth2.credentials
 
@@ -52,34 +49,6 @@
 with open(SERVICE_ACCOUNT_FILE) as fh:
     SERVICE_ACCOUNT_FILE_DATA = json.load(fh)
 
-SUBJECT_TOKEN_TEXT_FILE = os.path.join(DATA_DIR, "external_subject_token.txt")
-TOKEN_URL = "https://sts.googleapis.com/v1/token"
-AUDIENCE = "//iam.googleapis.com/projects/123456/locations/global/workloadIdentityPools/POOL_ID/providers/PROVIDER_ID"
-REGION_URL = "http://169.254.169.254/latest/meta-data/placement/availability-zone"
-SECURITY_CREDS_URL = "http://169.254.169.254/latest/meta-data/iam/security-credentials"
-CRED_VERIFICATION_URL = (
-    "https://sts.{region}.amazonaws.com?Action=GetCallerIdentity&Version=2011-06-15"
-)
-IDENTITY_POOL_DATA = {
-    "type": "external_account",
-    "audience": AUDIENCE,
-    "subject_token_type": "urn:ietf:params:oauth:token-type:jwt",
-    "token_url": TOKEN_URL,
-    "credential_source": {"file": SUBJECT_TOKEN_TEXT_FILE},
-}
-AWS_DATA = {
-    "type": "external_account",
-    "audience": AUDIENCE,
-    "subject_token_type": "urn:ietf:params:aws:token-type:aws4_request",
-    "token_url": TOKEN_URL,
-    "credential_source": {
-        "environment_id": "aws1",
-        "region_url": REGION_URL,
-        "url": SECURITY_CREDS_URL,
-        "regional_cred_verification_url": CRED_VERIFICATION_URL,
-    },
-}
-
 MOCK_CREDENTIALS = mock.Mock(spec=credentials.CredentialsWithQuotaProject)
 MOCK_CREDENTIALS.with_quota_project.return_value = MOCK_CREDENTIALS
 
@@ -88,12 +57,6 @@
     return_value=(MOCK_CREDENTIALS, mock.sentinel.project_id),
     autospec=True,
 )
-EXTERNAL_ACCOUNT_GET_PROJECT_ID_PATCH = mock.patch.object(
-    external_account.Credentials,
-    "get_project_id",
-    return_value=mock.sentinel.project_id,
-    autospec=True,
-)
 
 
 def test_load_credentials_from_missing_file():
@@ -222,92 +185,6 @@
     assert excinfo.match(r"missing fields")
 
 
-@EXTERNAL_ACCOUNT_GET_PROJECT_ID_PATCH
-def test_load_credentials_from_file_external_account_identity_pool(
-    get_project_id, tmpdir
-):
-    config_file = tmpdir.join("config.json")
-    config_file.write(json.dumps(IDENTITY_POOL_DATA))
-    credentials, project_id = _default.load_credentials_from_file(str(config_file))
-
-    assert isinstance(credentials, identity_pool.Credentials)
-    assert project_id is mock.sentinel.project_id
-    assert get_project_id.called
-
-
-@EXTERNAL_ACCOUNT_GET_PROJECT_ID_PATCH
-def test_load_credentials_from_file_external_account_aws(get_project_id, tmpdir):
-    config_file = tmpdir.join("config.json")
-    config_file.write(json.dumps(AWS_DATA))
-    credentials, project_id = _default.load_credentials_from_file(str(config_file))
-
-    assert isinstance(credentials, aws.Credentials)
-    assert project_id is mock.sentinel.project_id
-    assert get_project_id.called
-
-
-@EXTERNAL_ACCOUNT_GET_PROJECT_ID_PATCH
-def test_load_credentials_from_file_external_account_with_user_and_default_scopes(
-    get_project_id, tmpdir
-):
-    config_file = tmpdir.join("config.json")
-    config_file.write(json.dumps(IDENTITY_POOL_DATA))
-    credentials, project_id = _default.load_credentials_from_file(
-        str(config_file),
-        scopes=["https://www.google.com/calendar/feeds"],
-        default_scopes=["https://www.googleapis.com/auth/cloud-platform"],
-    )
-
-    assert isinstance(credentials, identity_pool.Credentials)
-    assert project_id is mock.sentinel.project_id
-    assert credentials.scopes == ["https://www.google.com/calendar/feeds"]
-    assert credentials.default_scopes == [
-        "https://www.googleapis.com/auth/cloud-platform"
-    ]
-
-
-@EXTERNAL_ACCOUNT_GET_PROJECT_ID_PATCH
-def test_load_credentials_from_file_external_account_with_quota_project(
-    get_project_id, tmpdir
-):
-    config_file = tmpdir.join("config.json")
-    config_file.write(json.dumps(IDENTITY_POOL_DATA))
-    credentials, project_id = _default.load_credentials_from_file(
-        str(config_file), quota_project_id="project-foo"
-    )
-
-    assert isinstance(credentials, identity_pool.Credentials)
-    assert project_id is mock.sentinel.project_id
-    assert credentials.quota_project_id == "project-foo"
-
-
-def test_load_credentials_from_file_external_account_bad_format(tmpdir):
-    filename = tmpdir.join("external_account_bad.json")
-    filename.write(json.dumps({"type": "external_account"}))
-
-    with pytest.raises(exceptions.DefaultCredentialsError) as excinfo:
-        _default.load_credentials_from_file(str(filename))
-
-    assert excinfo.match(
-        "Failed to load external account credentials from {}".format(str(filename))
-    )
-
-
-@EXTERNAL_ACCOUNT_GET_PROJECT_ID_PATCH
-def test_load_credentials_from_file_external_account_explicit_request(
-    get_project_id, tmpdir
-):
-    config_file = tmpdir.join("config.json")
-    config_file.write(json.dumps(IDENTITY_POOL_DATA))
-    credentials, project_id = _default.load_credentials_from_file(
-        str(config_file), request=mock.sentinel.request
-    )
-
-    assert isinstance(credentials, identity_pool.Credentials)
-    assert project_id is mock.sentinel.project_id
-    get_project_id.assert_called_with(credentials, request=mock.sentinel.request)
-
-
 @mock.patch.dict(os.environ, {}, clear=True)
 def test__get_explicit_environ_credentials_no_env():
     assert _default._get_explicit_environ_credentials() == (None, None)
@@ -321,34 +198,7 @@
 
     assert credentials is MOCK_CREDENTIALS
     assert project_id is mock.sentinel.project_id
-    load.assert_called_with(
-        "filename",
-        scopes=None,
-        default_scopes=None,
-        quota_project_id=None,
-        request=None,
-    )
-
-
-@LOAD_FILE_PATCH
-def test__get_explicit_environ_credentials_with_scopes_and_request(load, monkeypatch):
-    scopes = ["one", "two"]
-    monkeypatch.setenv(environment_vars.CREDENTIALS, "filename")
-
-    credentials, project_id = _default._get_explicit_environ_credentials(
-        request=mock.sentinel.request, scopes=scopes
-    )
-
-    assert credentials is MOCK_CREDENTIALS
-    assert project_id is mock.sentinel.project_id
-    # Request and scopes should be propagated.
-    load.assert_called_with(
-        "filename",
-        scopes=scopes,
-        default_scopes=None,
-        quota_project_id=None,
-        request=mock.sentinel.request,
-    )
+    load.assert_called_with("filename")
 
 
 @LOAD_FILE_PATCH
@@ -653,70 +503,3 @@
         sys.modules["google.auth.compute_engine"] = None
         sys.modules["google.auth.app_engine"] = None
         assert _default.default() == (MOCK_CREDENTIALS, mock.sentinel.project_id)
-
-
-@EXTERNAL_ACCOUNT_GET_PROJECT_ID_PATCH
-def test_default_environ_external_credentials(get_project_id, monkeypatch, tmpdir):
-    config_file = tmpdir.join("config.json")
-    config_file.write(json.dumps(IDENTITY_POOL_DATA))
-    monkeypatch.setenv(environment_vars.CREDENTIALS, str(config_file))
-
-    credentials, project_id = _default.default()
-
-    assert isinstance(credentials, identity_pool.Credentials)
-    assert project_id is mock.sentinel.project_id
-
-
-@EXTERNAL_ACCOUNT_GET_PROJECT_ID_PATCH
-def test_default_environ_external_credentials_with_user_and_default_scopes_and_quota_project_id(
-    get_project_id, monkeypatch, tmpdir
-):
-    config_file = tmpdir.join("config.json")
-    config_file.write(json.dumps(IDENTITY_POOL_DATA))
-    monkeypatch.setenv(environment_vars.CREDENTIALS, str(config_file))
-
-    credentials, project_id = _default.default(
-        scopes=["https://www.google.com/calendar/feeds"],
-        default_scopes=["https://www.googleapis.com/auth/cloud-platform"],
-        quota_project_id="project-foo",
-    )
-
-    assert isinstance(credentials, identity_pool.Credentials)
-    assert project_id is mock.sentinel.project_id
-    assert credentials.quota_project_id == "project-foo"
-    assert credentials.scopes == ["https://www.google.com/calendar/feeds"]
-    assert credentials.default_scopes == [
-        "https://www.googleapis.com/auth/cloud-platform"
-    ]
-
-
-@EXTERNAL_ACCOUNT_GET_PROJECT_ID_PATCH
-def test_default_environ_external_credentials_explicit_request(
-    get_project_id, monkeypatch, tmpdir
-):
-    config_file = tmpdir.join("config.json")
-    config_file.write(json.dumps(IDENTITY_POOL_DATA))
-    monkeypatch.setenv(environment_vars.CREDENTIALS, str(config_file))
-
-    credentials, project_id = _default.default(request=mock.sentinel.request)
-
-    assert isinstance(credentials, identity_pool.Credentials)
-    assert project_id is mock.sentinel.project_id
-    # default() will initialize new credentials via with_scopes_if_required
-    # and potentially with_quota_project.
-    # As a result the caller of get_project_id() will not match the returned
-    # credentials.
-    get_project_id.assert_called_with(mock.ANY, request=mock.sentinel.request)
-
-
-def test_default_environ_external_credentials_bad_format(monkeypatch, tmpdir):
-    filename = tmpdir.join("external_account_bad.json")
-    filename.write(json.dumps({"type": "external_account"}))
-    monkeypatch.setenv(environment_vars.CREDENTIALS, str(filename))
-
-    with pytest.raises(exceptions.DefaultCredentialsError) as excinfo:
-        _default.default()
-
-    assert excinfo.match(
-        "Failed to load external account credentials from {}".format(str(filename))
-    )