File: test_shared_cache_credential_async.py

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# ------------------------------------
# Copyright (c) Microsoft Corporation.
# Licensed under the MIT License.
# ------------------------------------
from unittest.mock import Mock, patch
from urllib.parse import urlparse

from azure.core.exceptions import ClientAuthenticationError
from azure.core.pipeline.policies import SansIOHTTPPolicy
from azure.identity import CredentialUnavailableError
from azure.identity.aio import SharedTokenCacheCredential
from azure.identity._constants import EnvironmentVariables
from azure.identity._internal.shared_token_cache import (
    KNOWN_ALIASES,
    MULTIPLE_ACCOUNTS,
    MULTIPLE_MATCHING_ACCOUNTS,
    NO_ACCOUNTS,
    NO_MATCHING_ACCOUNTS,
)
from azure.identity._internal.user_agent import USER_AGENT
from msal import TokenCache
import pytest

from helpers import build_aad_response, build_id_token, mock_response, Request
from helpers_async import async_validating_transport, AsyncMockTransport
from test_shared_cache_credential import get_account_event, populated_cache


def test_supported():
    """the cache is supported on Linux, macOS, Windows, so this should pass unless you're developing on e.g. FreeBSD"""
    assert SharedTokenCacheCredential.supported()


@pytest.mark.asyncio
async def test_no_scopes():
    """The credential should raise when get_token is called with no scopes"""

    credential = SharedTokenCacheCredential(_cache=TokenCache())
    with pytest.raises(ValueError):
        await credential.get_token()


@pytest.mark.asyncio
async def test_close():
    async def send(*_, **__):
        return mock_response(json_payload=build_aad_response(access_token="**"))

    transport = AsyncMockTransport(send=send)
    credential = SharedTokenCacheCredential(
        _cache=populated_cache(get_account_event("test@user", "uid", "utid")), transport=transport
    )

    # the credential doesn't open a transport session before one is needed, so we send a request
    await credential.get_token("scope")

    await credential.close()

    assert transport.__aexit__.call_count == 1


@pytest.mark.asyncio
async def test_context_manager():
    async def send(*_, **__):
        return mock_response(json_payload=build_aad_response(access_token="**"))

    transport = AsyncMockTransport(send=send)
    credential = SharedTokenCacheCredential(
        _cache=populated_cache(get_account_event("test@user", "uid", "utid")), transport=transport
    )

    # async with before initialization: credential should call aexit but not aenter
    async with credential:
        await credential.get_token("scope")

    assert transport.__aenter__.call_count == 0
    assert transport.__aexit__.call_count == 1

    # async with after initialization: credential should call aenter and aexit
    async with credential:
        await credential.get_token("scope")
        assert transport.__aenter__.call_count == 1
    assert transport.__aexit__.call_count == 2


@pytest.mark.asyncio
async def test_context_manager_no_cache():
    """the credential shouldn't open/close sessions when instantiated in an environment with no cache"""

    transport = AsyncMockTransport()

    with patch("azure.identity._internal.shared_token_cache.load_user_cache", Mock(side_effect=NotImplementedError)):
        credential = SharedTokenCacheCredential(transport=transport)

    async with credential:
        assert transport.__aenter__.call_count == 0

    assert transport.__aenter__.call_count == 0
    assert transport.__aexit__.call_count == 0


@pytest.mark.asyncio
async def test_policies_configurable():
    policy = Mock(spec_set=SansIOHTTPPolicy, on_request=Mock())

    async def send(*_, **__):
        return mock_response(json_payload=build_aad_response(access_token="**"))

    credential = SharedTokenCacheCredential(
        _cache=populated_cache(get_account_event("test@user", "uid", "utid")),
        policies=[policy],
        transport=Mock(send=send),
    )

    await credential.get_token("scope")

    assert policy.on_request.called


@pytest.mark.asyncio
async def test_user_agent():
    transport = async_validating_transport(
        requests=[Request(required_headers={"User-Agent": USER_AGENT})],
        responses=[mock_response(json_payload=build_aad_response(access_token="**"))],
    )

    credential = SharedTokenCacheCredential(
        _cache=populated_cache(get_account_event("test@user", "uid", "utid")), transport=transport
    )

    await credential.get_token("scope")


@pytest.mark.parametrize("authority", ("localhost", "https://localhost"))
def test_authority(authority):
    """the credential should accept an authority, with or without scheme, as an argument or environment variable"""

    parsed_authority = urlparse(authority)
    expected_netloc = parsed_authority.netloc or authority  # "localhost" parses to netloc "", path "localhost"

    class MockCredential(SharedTokenCacheCredential):
        def _get_auth_client(self, authority=None, **kwargs):
            actual = urlparse(authority)
            assert actual.scheme == "https"
            assert actual.netloc == expected_netloc

    transport = Mock(send=Mock(side_effect=Exception("credential shouldn't send a request")))
    MockCredential(_cache=TokenCache(), authority=authority, transport=transport)

    with patch.dict("os.environ", {EnvironmentVariables.AZURE_AUTHORITY_HOST: authority}, clear=True):
        MockCredential(_cache=TokenCache(), authority=authority, transport=transport)


@pytest.mark.asyncio
async def test_empty_cache():
    """the credential should raise CredentialUnavailableError when the cache is empty"""

    with pytest.raises(CredentialUnavailableError, match=NO_ACCOUNTS):
        await SharedTokenCacheCredential(_cache=TokenCache()).get_token("scope")
    with pytest.raises(CredentialUnavailableError, match=NO_ACCOUNTS):
        await SharedTokenCacheCredential(_cache=TokenCache(), username="not@cache").get_token("scope")
    with pytest.raises(CredentialUnavailableError, match=NO_ACCOUNTS):
        await SharedTokenCacheCredential(_cache=TokenCache(), tenant_id="not-cached").get_token("scope")
    with pytest.raises(CredentialUnavailableError, match=NO_ACCOUNTS):
        credential = SharedTokenCacheCredential(_cache=TokenCache(), tenant_id="not-cached", username="not@cache")
        await credential.get_token("scope")


@pytest.mark.asyncio
async def test_no_matching_account_for_username():
    """one cached account, username specified, username doesn't match -> credential should raise"""

    upn = "spam@eggs"
    tenant = "some-guid"
    account = get_account_event(username=upn, uid="uid", utid=tenant, refresh_token="refresh-token")
    cache = populated_cache(account)

    with pytest.raises(CredentialUnavailableError) as ex:
        await SharedTokenCacheCredential(_cache=cache, username="not" + upn).get_token("scope")

    assert ex.value.message.startswith(NO_MATCHING_ACCOUNTS[: NO_MATCHING_ACCOUNTS.index("{")])
    assert "not" + upn in ex.value.message


@pytest.mark.asyncio
async def test_no_matching_account_for_tenant():
    """one cached account, tenant specified, tenant doesn't match -> credential should raise"""

    upn = "spam@eggs"
    tenant = "some-guid"
    account = get_account_event(username=upn, uid="uid", utid=tenant, refresh_token="refresh-token")
    cache = populated_cache(account)

    with pytest.raises(CredentialUnavailableError) as ex:
        await SharedTokenCacheCredential(_cache=cache, tenant_id="not-" + tenant).get_token("scope")

    assert ex.value.message.startswith(NO_MATCHING_ACCOUNTS[: NO_MATCHING_ACCOUNTS.index("{")])
    assert "not-" + tenant in ex.value.message


@pytest.mark.asyncio
async def test_no_matching_account_for_tenant_and_username():
    """one cached account, tenant and username specified, neither match -> credential should raise"""

    upn = "spam@eggs"
    tenant = "some-guid"
    account = get_account_event(username=upn, uid="uid", utid=tenant, refresh_token="refresh-token")
    cache = populated_cache(account)

    with pytest.raises(CredentialUnavailableError) as ex:
        await SharedTokenCacheCredential(_cache=cache, tenant_id="not-" + tenant, username="not" + upn).get_token(
            "scope"
        )

    assert ex.value.message.startswith(NO_MATCHING_ACCOUNTS[: NO_MATCHING_ACCOUNTS.index("{")])
    assert "not" + upn in ex.value.message and "not-" + tenant in ex.value.message


@pytest.mark.asyncio
async def test_no_matching_account_for_tenant_or_username():
    """two cached accounts, username and tenant specified, one account matches each -> credential should raise"""

    refresh_token_a = "refresh-token-a"
    refresh_token_b = "refresh-token-b"
    upn_a = "a@foo"
    upn_b = "b@foo"
    tenant_a = "tenant-a"
    tenant_b = "tenant-b"
    account_a = get_account_event(username=upn_a, uid="uid_a", utid=tenant_a, refresh_token=refresh_token_a)
    account_b = get_account_event(username=upn_b, uid="uid_b", utid=tenant_b, refresh_token=refresh_token_b)
    cache = populated_cache(account_a, account_b)

    transport = Mock(side_effect=Exception())  # credential shouldn't use the network

    credential = SharedTokenCacheCredential(username=upn_a, tenant_id=tenant_b, _cache=cache, transport=transport)
    with pytest.raises(CredentialUnavailableError) as ex:
        await credential.get_token("scope")
    assert ex.value.message.startswith(NO_MATCHING_ACCOUNTS[: NO_MATCHING_ACCOUNTS.index("{")])
    assert upn_a in ex.value.message and tenant_b in ex.value.message

    credential = SharedTokenCacheCredential(username=upn_b, tenant_id=tenant_a, _cache=cache, transport=transport)
    with pytest.raises(CredentialUnavailableError) as ex:
        await credential.get_token("scope")
    assert ex.value.message.startswith(NO_MATCHING_ACCOUNTS[: NO_MATCHING_ACCOUNTS.index("{")])
    assert upn_b in ex.value.message and tenant_a in ex.value.message


@pytest.mark.asyncio
async def test_single_account_matching_username():
    """one cached account, username specified, username matches -> credential should auth that account"""

    upn = "spam@eggs"
    refresh_token = "refresh-token"
    scope = "scope"
    account = get_account_event(uid="uid_a", utid="utid", username=upn, refresh_token=refresh_token)
    cache = populated_cache(account)

    expected_token = "***"
    transport = async_validating_transport(
        requests=[Request(required_data={"refresh_token": refresh_token, "scope": scope})],
        responses=[mock_response(json_payload=build_aad_response(access_token=expected_token))],
    )
    credential = SharedTokenCacheCredential(_cache=cache, transport=transport, username=upn)
    token = await credential.get_token(scope)
    assert token.token == expected_token


@pytest.mark.asyncio
async def test_single_account_matching_tenant():
    """one cached account, tenant specified, tenant matches -> credential should auth that account"""

    tenant_id = "tenant-id"
    refresh_token = "refresh-token"
    scope = "scope"
    account = get_account_event(uid="uid_a", utid=tenant_id, username="spam@eggs", refresh_token=refresh_token)
    cache = populated_cache(account)

    expected_token = "***"
    transport = async_validating_transport(
        requests=[Request(required_data={"refresh_token": refresh_token, "scope": scope})],
        responses=[mock_response(json_payload=build_aad_response(access_token=expected_token))],
    )
    credential = SharedTokenCacheCredential(_cache=cache, transport=transport, tenant_id=tenant_id)
    token = await credential.get_token(scope)
    assert token.token == expected_token


@pytest.mark.asyncio
async def test_single_account_matching_tenant_and_username():
    """one cached account, tenant and username specified, both match -> credential should auth that account"""

    upn = "spam@eggs"
    tenant_id = "tenant-id"
    refresh_token = "refresh-token"
    scope = "scope"
    account = get_account_event(uid="uid_a", utid=tenant_id, username=upn, refresh_token=refresh_token)
    cache = populated_cache(account)

    expected_token = "***"
    transport = async_validating_transport(
        requests=[Request(required_data={"refresh_token": refresh_token, "scope": scope})],
        responses=[mock_response(json_payload=build_aad_response(access_token=expected_token))],
    )
    credential = SharedTokenCacheCredential(_cache=cache, transport=transport, tenant_id=tenant_id, username=upn)
    token = await credential.get_token(scope)
    assert token.token == expected_token


@pytest.mark.asyncio
async def test_single_account():
    """one cached account, no username specified -> credential should auth that account"""

    refresh_token = "refresh-token"
    scope = "scope"
    account = get_account_event(uid="uid_a", utid="utid", username="spam@eggs", refresh_token=refresh_token)
    cache = populated_cache(account)

    expected_token = "***"
    transport = async_validating_transport(
        requests=[Request(required_data={"refresh_token": refresh_token, "scope": scope})],
        responses=[mock_response(json_payload=build_aad_response(access_token=expected_token))],
    )
    credential = SharedTokenCacheCredential(_cache=cache, transport=transport)

    token = await credential.get_token(scope)
    assert token.token == expected_token


@pytest.mark.asyncio
async def test_no_refresh_token():
    """one cached account, account has no refresh token -> credential should raise"""

    account = get_account_event(uid="uid_a", utid="utid", username="spam@eggs", refresh_token=None)
    cache = populated_cache(account)

    transport = Mock(side_effect=Exception())  # credential shouldn't use the network

    credential = SharedTokenCacheCredential(_cache=cache, transport=transport)
    with pytest.raises(CredentialUnavailableError, match=NO_ACCOUNTS):
        await credential.get_token("scope")

    credential = SharedTokenCacheCredential(_cache=cache, transport=transport, username="not@cache")
    with pytest.raises(CredentialUnavailableError, match=NO_ACCOUNTS):
        await credential.get_token("scope")


@pytest.mark.asyncio
async def test_two_accounts_no_username_or_tenant():
    """two cached accounts, no username or tenant specified -> credential should raise"""

    upn_a = "a@foo"
    upn_b = "b@foo"
    account_a = get_account_event(username=upn_a, uid="uid_a", utid="utid")
    account_b = get_account_event(username=upn_b, uid="uid_b", utid="utid")
    cache = populated_cache(account_a, account_b)

    # credential can't select an identity => it shouldn't use the network
    transport = Mock(side_effect=Exception())

    # two users in the cache, no username specified -> CredentialUnavailableError
    credential = SharedTokenCacheCredential(_cache=cache, transport=transport)
    with pytest.raises(ClientAuthenticationError, match=MULTIPLE_ACCOUNTS) as ex:
        await credential.get_token("scope")


@pytest.mark.asyncio
async def test_two_accounts_username_specified():
    """two cached accounts, username specified, one account matches -> credential should auth that account"""

    scope = "scope"
    expected_refresh_token = "refresh-token-a"
    upn_a = "a@foo"
    upn_b = "b@foo"
    account_a = get_account_event(username=upn_a, uid="uid_a", utid="utid", refresh_token=expected_refresh_token)
    account_b = get_account_event(username=upn_b, uid="uid_b", utid="utid", refresh_token="refresh_token_b")
    cache = populated_cache(account_a, account_b)

    expected_token = "***"
    transport = async_validating_transport(
        requests=[Request(required_data={"refresh_token": expected_refresh_token, "scope": scope})],
        responses=[mock_response(json_payload=build_aad_response(access_token=expected_token))],
    )
    credential = SharedTokenCacheCredential(username=upn_a, _cache=cache, transport=transport)
    token = await credential.get_token(scope)
    assert token.token == expected_token


@pytest.mark.asyncio
async def test_two_accounts_tenant_specified():
    """two cached accounts, tenant specified, one account matches -> credential should auth that account"""

    scope = "scope"
    expected_refresh_token = "refresh-token-a"
    upn_a = "a@foo"
    upn_b = "b@foo"
    tenant_id = "tenant-id"
    account_a = get_account_event(username=upn_a, uid="uid_a", utid=tenant_id, refresh_token=expected_refresh_token)
    account_b = get_account_event(username=upn_b, uid="uid_b", utid="utid", refresh_token="refresh_token_b")
    cache = populated_cache(account_a, account_b)

    expected_token = "***"
    transport = async_validating_transport(
        requests=[Request(required_data={"refresh_token": expected_refresh_token, "scope": scope})],
        responses=[mock_response(json_payload=build_aad_response(access_token=expected_token))],
    )
    credential = SharedTokenCacheCredential(tenant_id=tenant_id, _cache=cache, transport=transport)
    token = await credential.get_token(scope)
    assert token.token == expected_token


@pytest.mark.asyncio
async def test_two_accounts_tenant_and_username_specified():
    """two cached accounts, tenant and username specified, one account matches both -> credential should auth that account"""

    scope = "scope"
    expected_refresh_token = "refresh-token-a"
    upn_a = "a@foo"
    upn_b = "b@foo"
    tenant_id = "tenant-id"
    account_a = get_account_event(username=upn_a, uid="uid_a", utid=tenant_id, refresh_token=expected_refresh_token)
    account_b = get_account_event(username=upn_b, uid="uid_b", utid="utid", refresh_token="refresh_token_b")
    cache = populated_cache(account_a, account_b)

    expected_token = "***"
    transport = async_validating_transport(
        requests=[Request(required_data={"refresh_token": expected_refresh_token, "scope": scope})],
        responses=[mock_response(json_payload=build_aad_response(access_token=expected_token))],
    )
    credential = SharedTokenCacheCredential(tenant_id=tenant_id, username=upn_a, _cache=cache, transport=transport)
    token = await credential.get_token(scope)
    assert token.token == expected_token


@pytest.mark.asyncio
async def test_same_username_different_tenants():
    """two cached accounts, same username, different tenants"""

    access_token_a = "access-token-a"
    access_token_b = "access-token-b"
    refresh_token_a = "refresh-token-a"
    refresh_token_b = "refresh-token-b"

    upn = "spam@eggs"
    tenant_a = "tenant-a"
    tenant_b = "tenant-b"
    account_a = get_account_event(username=upn, uid="another-guid", utid=tenant_a, refresh_token=refresh_token_a)
    account_b = get_account_event(username=upn, uid="more-guid", utid=tenant_b, refresh_token=refresh_token_b)
    cache = populated_cache(account_a, account_b)

    # with no tenant specified the credential can't select an identity
    transport = Mock(side_effect=Exception())  # (so it shouldn't use the network)
    credential = SharedTokenCacheCredential(username=upn, _cache=cache, transport=transport)
    with pytest.raises(CredentialUnavailableError) as ex:
        await credential.get_token("scope")

    assert ex.value.message.startswith(MULTIPLE_MATCHING_ACCOUNTS[: MULTIPLE_MATCHING_ACCOUNTS.index("{")])
    assert upn in ex.value.message

    # with tenant specified, the credential should auth the matching account
    scope = "scope"
    transport = async_validating_transport(
        requests=[Request(required_data={"refresh_token": refresh_token_a, "scope": scope})],
        responses=[mock_response(json_payload=build_aad_response(access_token=access_token_a))],
    )
    credential = SharedTokenCacheCredential(tenant_id=tenant_a, _cache=cache, transport=transport)
    token = await credential.get_token(scope)
    assert token.token == access_token_a

    transport = async_validating_transport(
        requests=[Request(required_data={"refresh_token": refresh_token_b, "scope": scope})],
        responses=[mock_response(json_payload=build_aad_response(access_token=access_token_b))],
    )
    credential = SharedTokenCacheCredential(tenant_id=tenant_b, _cache=cache, transport=transport)
    token = await credential.get_token(scope)
    assert token.token == access_token_b


@pytest.mark.asyncio
async def test_same_tenant_different_usernames():
    """two cached accounts, same tenant, different usernames"""

    access_token_a = "access-token-a"
    access_token_b = "access-token-b"
    refresh_token_a = "refresh-token-a"
    refresh_token_b = "refresh-token-b"

    upn_a = "spam@eggs"
    upn_b = "eggs@spam"
    tenant_id = "the-tenant"
    account_a = get_account_event(username=upn_a, uid="another-guid", utid=tenant_id, refresh_token=refresh_token_a)
    account_b = get_account_event(username=upn_b, uid="more-guid", utid=tenant_id, refresh_token=refresh_token_b)
    cache = populated_cache(account_a, account_b)

    # with no username specified the credential can't select an identity
    transport = Mock(side_effect=Exception())  # (so it shouldn't use the network)
    credential = SharedTokenCacheCredential(tenant_id=tenant_id, _cache=cache, transport=transport)
    with pytest.raises(CredentialUnavailableError) as ex:
        await credential.get_token("scope")

    assert ex.value.message.startswith(MULTIPLE_MATCHING_ACCOUNTS[: MULTIPLE_MATCHING_ACCOUNTS.index("{")])
    assert tenant_id in ex.value.message

    # with a username specified, the credential should auth the matching account
    scope = "scope"
    transport = async_validating_transport(
        requests=[Request(required_data={"refresh_token": refresh_token_b, "scope": scope})],
        responses=[mock_response(json_payload=build_aad_response(access_token=access_token_a))],
    )
    credential = SharedTokenCacheCredential(username=upn_b, _cache=cache, transport=transport)
    token = await credential.get_token(scope)
    assert token.token == access_token_a

    transport = async_validating_transport(
        requests=[Request(required_data={"refresh_token": refresh_token_a, "scope": scope})],
        responses=[mock_response(json_payload=build_aad_response(access_token=access_token_a))],
    )
    credential = SharedTokenCacheCredential(username=upn_a, _cache=cache, transport=transport)
    token = await credential.get_token(scope)
    assert token.token == access_token_a


@pytest.mark.asyncio
async def test_authority_aliases():
    """the credential should use a refresh token valid for any known alias of its authority"""

    expected_access_token = "access-token"

    for authority in KNOWN_ALIASES:
        # cache a token for this authority
        expected_refresh_token = authority.replace(".", "")
        account = get_account_event(
            "spam@eggs", "uid", "tenant", authority=authority, refresh_token=expected_refresh_token
        )
        cache = populated_cache(account)

        # the token should be acceptable for this authority itself
        transport = async_validating_transport(
            requests=[Request(authority=authority, required_data={"refresh_token": expected_refresh_token})],
            responses=[mock_response(json_payload=build_aad_response(access_token=expected_access_token))],
        )
        credential = SharedTokenCacheCredential(authority=authority, _cache=cache, transport=transport)
        token = await credential.get_token("scope")
        assert token.token == expected_access_token

        # it should also be acceptable for every known alias of this authority
        for alias in KNOWN_ALIASES[authority]:
            transport = async_validating_transport(
                requests=[Request(authority=alias, required_data={"refresh_token": expected_refresh_token})],
                responses=[mock_response(json_payload=build_aad_response(access_token=expected_access_token))],
            )
            credential = SharedTokenCacheCredential(authority=alias, _cache=cache, transport=transport)
            token = await credential.get_token("scope")
            assert token.token == expected_access_token


@pytest.mark.asyncio
async def test_authority_with_no_known_alias():
    """given an appropriate token, an authority with no known aliases should work"""

    authority = "unknown.authority"
    expected_access_token = "access-token"
    expected_refresh_token = "refresh-token"
    account = get_account_event("spam@eggs", "uid", "tenant", authority=authority, refresh_token=expected_refresh_token)
    cache = populated_cache(account)
    transport = async_validating_transport(
        requests=[Request(authority=authority, required_data={"refresh_token": expected_refresh_token})],
        responses=[mock_response(json_payload=build_aad_response(access_token=expected_access_token))],
    )
    credential = SharedTokenCacheCredential(authority=authority, _cache=cache, transport=transport)
    token = await credential.get_token("scope")
    assert token.token == expected_access_token


@pytest.mark.asyncio
async def test_authority_environment_variable():
    """the credential should accept an authority by environment variable when none is otherwise specified"""

    authority = "localhost"
    expected_access_token = "access-token"
    expected_refresh_token = "refresh-token"
    account = get_account_event("spam@eggs", "uid", "tenant", authority=authority, refresh_token=expected_refresh_token)
    cache = populated_cache(account)
    transport = async_validating_transport(
        requests=[Request(authority=authority, required_data={"refresh_token": expected_refresh_token})],
        responses=[mock_response(json_payload=build_aad_response(access_token=expected_access_token))],
    )
    with patch.dict("os.environ", {EnvironmentVariables.AZURE_AUTHORITY_HOST: authority}, clear=True):
        credential = SharedTokenCacheCredential(transport=transport, _cache=cache)
    token = await credential.get_token("scope")
    assert token.token == expected_access_token


@pytest.mark.asyncio
async def test_allow_unencrypted_cache():
    """The credential should use an unencrypted cache when encryption is unavailable and the user explicitly allows it.

    This test was written when Linux was the only platform on which encryption may not be available.
    """

    platform_patch = patch("azure.identity._internal.persistent_cache.sys.platform", "linux2")
    platform_patch.start()

    msal_extensions_patch = patch("azure.identity._internal.persistent_cache.msal_extensions")
    mock_extensions = msal_extensions_patch.start()

    # the credential should prefer an encrypted cache even when the user allows an unencrypted one
    SharedTokenCacheCredential(allow_unencrypted_cache=True)
    assert mock_extensions.PersistedTokenCache.called_with(mock_extensions.LibsecretPersistence)
    mock_extensions.PersistedTokenCache.reset_mock()

    # (when LibsecretPersistence's dependencies aren't available, constructing it raises ImportError)
    mock_extensions.LibsecretPersistence = Mock(side_effect=ImportError)

    # encryption unavailable, no opt in to unencrypted cache -> credential should be unavailable
    credential = SharedTokenCacheCredential()
    assert mock_extensions.PersistedTokenCache.call_count == 0
    with pytest.raises(CredentialUnavailableError):
        await credential.get_token("scope")

    # still no encryption, but now we allow the unencrypted fallback
    SharedTokenCacheCredential(allow_unencrypted_cache=True)
    assert mock_extensions.PersistedTokenCache.called_with(mock_extensions.FilePersistence)

    msal_extensions_patch.stop()
    platform_patch.stop()


@pytest.mark.asyncio
async def test_initialization():
    """the credential should attempt to load the cache only once, when it's first needed"""

    with patch("azure.identity._internal.persistent_cache._load_persistent_cache") as mock_cache_loader:
        mock_cache_loader.side_effect = Exception("it didn't work")

        credential = SharedTokenCacheCredential()
        assert mock_cache_loader.call_count == 0

        for _ in range(2):
            with pytest.raises(CredentialUnavailableError):
                await credential.get_token("scope")
            assert mock_cache_loader.call_count == 1