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Unit Tests

The unit tests for the Prowler checks varies between each provider supported.

Here we left some good reads about unit testing and things we've learnt through all the process.

Python Testing

Where to patch

Utils to trace mocking and test execution

General Recommendations

When creating tests for some provider's checks we follow these guidelines trying to cover as much test scenarios as possible:

  1. Create a test without resource to generate 0 findings, because Prowler will generate 0 findings if a service does not contain the resources the check is looking for audit.
  2. Create test to generate both a PASS and a FAIL result.
  3. Create tests with more than 1 resource to evaluate how the check behaves and if the number of findings is right.

How to run Prowler tests

To run the Prowler test suite you need to install the testing dependencies already included in the pyproject.toml file. If you didn't install it yet please read the developer guide introduction here.

Then in the project's root path execute pytest -n auto -vvv -s -x or use the Makefile with make test.

Other commands to run tests:

  • Run tests for a provider: pytest -n auto -vvv -s -x tests/providers/<provider>/services
  • Run tests for a provider service: pytest -n auto -vvv -s -x tests/providers/<provider>/services/<service>
  • Run tests for a provider check: pytest -n auto -vvv -s -x tests/providers/<provider>/services/<service>/<check>
Note

Refer to the pytest documentation documentation for more information.

AWS

For the AWS provider we have ways to test a Prowler check based on the following criteria:

Note

We use and contribute to the Moto library which allows us to easily mock out tests based on AWS infrastructure. It's awesome!

  • AWS API calls covered by Moto:
    • Service tests with @mock_<service>
    • Checks tests with @mock_<service>
  • AWS API calls not covered by Moto:
    • Service test with mock_make_api_call
    • Checks tests with MagicMock
  • AWS API calls partially covered by Moto:
    • Service test with @mock_<service> and mock_make_api_call
    • Checks tests with @mock_<service> and mock_make_api_call

In the following section we are going to explain all of the above scenarios with examples. The main difference between those scenarios comes from if the Moto library covers the AWS API calls made by the service. You can check the covered API calls here.

An important point for the AWS testing is that in each check we MUST have a unique audit_info which is the key object during the AWS execution to isolate the test execution.

Check the Audit Info section to get more details.

# We need to import the AWS_Audit_Info and the Audit_Metadata
# to set the audit_info to call AWS APIs
from prowler.providers.aws.lib.audit_info.models import AWS_Audit_Info
from prowler.providers.common.models import Audit_Metadata

AWS_ACCOUNT_NUMBER = "123456789012"

def set_mocked_audit_info(self):
  audit_info = AWS_Audit_Info(
      session_config=None,
      original_session=None,
      audit_session=session.Session(
          profile_name=None,
          botocore_session=None,
      ),
      audit_config=None,
      audited_account=AWS_ACCOUNT_NUMBER,
      audited_account_arn=f"arn:aws:iam::{AWS_ACCOUNT_NUMBER}:root",
      audited_user_id=None,
      audited_partition="aws",
      audited_identity_arn=None,
      profile=None,
      profile_region=None,
      credentials=None,
      assumed_role_info=None,
      audited_regions=["us-east-1", "eu-west-1"],
      organizations_metadata=None,
      audit_resources=None,
      mfa_enabled=False,
      audit_metadata=Audit_Metadata(
          services_scanned=0,
          expected_checks=[],
          completed_checks=0,
          audit_progress=0,
      ),
  )

  return audit_info

Checks

For the AWS tests examples we are going to use the tests for the iam_password_policy_uppercase check.

This section is going to be divided based on the API coverage of the Moto library.

API calls covered

If the Moto library covers the API calls we want to test, we can use the @mock_<service> decorator. This will mocked out all the API calls made to AWS keeping the state within the code decorated, in this case the test function.

# We need to import the unittest.mock to allow us to patch some objects
# not to use shared ones between test, hence to isolate the test
from unittest import mock

# Boto3 client and session to call the AWS APIs
from boto3 import client, session

# Moto decorator for the IAM service we want to mock
from moto import mock_iam

# Constants used
AWS_ACCOUNT_NUMBER = "123456789012"
AWS_REGION = "us-east-1"


# We always name the test classes like Test_<check_name>
class Test_iam_password_policy_uppercase:

  # We include the Moto decorator for the service we want to use
  # You can include more than one if two or more services are
  # involved in test
  @mock_iam
  # We name the tests with test_<service>_<check_name>_<test_action>
  def test_iam_password_policy_no_uppercase_flag(self):
    # First, we have to create an IAM client
    iam_client = client("iam", region_name=AWS_REGION)

    # Then, since all the AWS accounts have a password
    # policy we want to set to False the RequireUppercaseCharacters
    iam_client.update_account_password_policy(RequireUppercaseCharacters=False)

    # We set a mocked audit_info for AWS not to share the same audit state
    # between checks
    current_audit_info = self.set_mocked_audit_info()

    # The Prowler service import MUST be made within the decorated
    # code not to make real API calls to the AWS service.
    from prowler.providers.aws.services.iam.iam_service import IAM

    # Prowler for AWS uses a shared object called `current_audit_info` where it stores
    # the audit's state, credentials and configuration.
    with mock.patch(
        "prowler.providers.aws.lib.audit_info.audit_info.current_audit_info",
        new=current_audit_info,
    ),
    # We have to mock also the iam_client from the check to enforce that the iam_client used is the one
    # created within this check because patch != import, and if you execute tests in parallel some objects
    # can be already initialised hence the check won't be isolated
      mock.patch(
        "prowler.providers.aws.services.iam.iam_password_policy_uppercase.iam_password_policy_uppercase.iam_client",
        new=IAM(current_audit_info),
    ):
        # We import the check within the two mocks not to initialise the iam_client with some shared information from
        # the current_audit_info or the IAM service.
        from prowler.providers.aws.services.iam.iam_password_policy_uppercase.iam_password_policy_uppercase import (
            iam_password_policy_uppercase,
        )

        # Once imported, we only need to instantiate the check's class
        check = iam_password_policy_uppercase()

        # And then, call the execute() function to run the check
        # against the IAM client we've set up.
        result = check.execute()

        # Last but not least, we need to assert all the fields
        # from the check's results
        assert len(results) == 1
        assert result[0].status == "FAIL"
        assert result[0].status_extended == "IAM password policy does not require at least one uppercase letter."
        assert result[0].resource_arn == f"arn:aws:iam::{AWS_ACCOUNT_NUMBER}:root"
        assert result[0].resource_id == AWS_ACCOUNT_NUMBER
        assert result[0].resource_tags == []
        assert result[0].region == AWS_REGION

API calls not covered

If the IAM service for the check's we want to test is not covered by Moto, we have to inject the objects in the service client using MagicMock. As we have pointed above, we cannot instantiate the service since it will make real calls to the AWS APIs.

Note

The following example uses the IAM GetAccountPasswordPolicy which is covered by Moto but this is only for demonstration purposes.

The following code shows how to use MagicMock to create the service objects.

# We need to import the unittest.mock to allow us to patch some objects
# not to use shared ones between test, hence to isolate the test
from unittest import mock

# Constants used
AWS_ACCOUNT_NUMBER = "123456789012"
AWS_REGION = "us-east-1"


# We always name the test classes like Test_<check_name>
class Test_iam_password_policy_uppercase:

  # We name the tests with test_<service>_<check_name>_<test_action>
  def test_iam_password_policy_no_uppercase_flag(self):
    # Mocked client with MagicMock
    mocked_iam_client = mock.MagicMock

    # Since the IAM Password Policy has their own model we have to import it
    from prowler.providers.aws.services.iam.iam_service import PasswordPolicy

    # Create the mock PasswordPolicy object
    mocked_iam_client.password_policy = PasswordPolicy(
        length=5,
        symbols=True,
        numbers=True,
        # We set the value to False to test the check
        uppercase=False,
        lowercase=True,
        allow_change=False,
        expiration=True,
    )

    # We set a mocked audit_info for AWS not to share the same audit state
    # between checks
    current_audit_info = self.set_mocked_audit_info()

    # In this scenario we have to mock also the IAM service and the iam_client from the check to enforce    # that the iam_client used is the one created within this check because patch != import, and if you     # execute tests in parallel some objects can be already initialised hence the check won't be isolated.
    # In this case we don't use the Moto decorator, we use the mocked IAM client for both objects
    with mock.patch(
        "prowler.providers.aws.services.iam.iam_service.IAM",
        new=mocked_iam_client,
    ), mock.patch(
        "prowler.providers.aws.services.iam.iam_client.iam_client",
        new=mocked_iam_client,
    ):
        # We import the check within the two mocks not to initialise the iam_client with some shared information from
        # the current_audit_info or the IAM service.
        from prowler.providers.aws.services.iam.iam_password_policy_uppercase.iam_password_policy_uppercase import (
            iam_password_policy_uppercase,
        )

        # Once imported, we only need to instantiate the check's class
        check = iam_password_policy_uppercase()

        # And then, call the execute() function to run the check
        # against the IAM client we've set up.
        result = check.execute()

        # Last but not least, we need to assert all the fields
        # from the check's results
        assert len(results) == 1
        assert result[0].status == "FAIL"
        assert result[0].status_extended == "IAM password policy does not require at least one uppercase letter."
        assert result[0].resource_arn == f"arn:aws:iam::{AWS_ACCOUNT_NUMBER}:root"
        assert result[0].resource_id == AWS_ACCOUNT_NUMBER
        assert result[0].resource_tags == []
        assert result[0].region == AWS_REGION

As it can be seen in the above scenarios, the check execution should always be into the context of mocked/patched objects. This way we ensure it reviews only the objects created under the scope the test.

API calls partially covered

If the API calls we want to use in the service are partially covered by the Moto decorator we have to create our own mocked API calls to use it in combination.

To do so, you need to mock the botocore.client.BaseClient._make_api_call function, which is the Boto3 function in charge of making the real API call to the AWS APIs, using mock.patch <https://docs.python.org/3/library/unittest.mock.html#patch>:

import boto3
import botocore
from unittest.mock import patch
from moto import mock_iam

# Original botocore _make_api_call function
orig = botocore.client.BaseClient._make_api_call

# Mocked botocore _make_api_call function
def mock_make_api_call(self, operation_name, kwarg):
    # As you can see the operation_name has the get_account_password_policy snake_case form but
    # we are using the GetAccountPasswordPolicy form.
    # Rationale -> https://github.com/boto/botocore/blob/develop/botocore/client.py#L810:L816
    if operation_name == 'GetAccountPasswordPolicy':
        return {
            'PasswordPolicy': {
                'MinimumPasswordLength': 123,
                'RequireSymbols': True|False,
                'RequireNumbers': True|False,
                'RequireUppercaseCharacters': True|False,
                'RequireLowercaseCharacters': True|False,
                'AllowUsersToChangePassword': True|False,
                'ExpirePasswords': True|False,
                'MaxPasswordAge': 123,
                'PasswordReusePrevention': 123,
                'HardExpiry': True|False
            }
        }
    # If we don't want to patch the API call
    return orig(self, operation_name, kwarg)

# We always name the test classes like Test_<check_name>
class Test_iam_password_policy_uppercase:

  # We include the custom API call mock decorator for the service we want to use
  @patch("botocore.client.BaseClient._make_api_call", new=mock_make_api_call)
  # We include also the IAM Moto decorator for the API calls supported
  @mock_iam
  # We name the tests with test_<service>_<check_name>_<test_action>
  def test_iam_password_policy_no_uppercase_flag(self):
    # Check the previous section to see the check test since is the same

Note that this does not use Moto, to keep it simple, but if you use any moto-decorators in addition to the patch, the call to orig(self, operation_name, kwarg) will be intercepted by Moto.

Note

The above code comes from here https://docs.getmoto.org/en/latest/docs/services/patching_other_services.html

Mocking more than one service

If the test your are creating belongs to a check that uses more than one provider service, you should mock each of the services used. For example, the check cloudtrail_logs_s3_bucket_access_logging_enabled requires the CloudTrail and the S3 client, hence the service's mock part of the test will be as follows:

with mock.patch(
    "prowler.providers.aws.lib.audit_info.audit_info.current_audit_info",
    new=mock_audit_info,
), mock.patch(
    "prowler.providers.aws.services.cloudtrail.cloudtrail_logs_s3_bucket_access_logging_enabled.cloudtrail_logs_s3_bucket_access_logging_enabled.cloudtrail_client",
    new=Cloudtrail(mock_audit_info),
), mock.patch(
    "prowler.providers.aws.services.cloudtrail.cloudtrail_logs_s3_bucket_access_logging_enabled.cloudtrail_logs_s3_bucket_access_logging_enabled.s3_client",
    new=S3(mock_audit_info),
):

As you can see in the above code, it is required to mock the AWS audit info and both services used.

Patching vs. Importing

This is an important topic within the Prowler check's unit testing. Due to the dynamic nature of the check's load, the process of importing the service client from a check is the following:

  1. <check>.py:
    from prowler.providers.<provider>.services.<service>.<service>_client import <service>_client
    
  2. <service>_client.py:
    from prowler.providers.<provider>.lib.audit_info.audit_info import audit_info
    from prowler.providers.<provider>.services.<service>.<service>_service import <SERVICE>
    
    <service>_client = <SERVICE>(audit_info)
    

Due to the above import path it's not the same to patch the following objects because if you run a bunch of tests, either in parallel or not, some clients can be already instantiated by another check, hence your test execution will be using another test's service instance:

  • <service>_client imported at <check>.py
  • <service>_client initialised at <service>_client.py
  • <SERVICE> imported at <service>_client.py

A useful read about this topic can be found in the following article: https://stackoverflow.com/questions/8658043/how-to-mock-an-import

Different ways to mock the service client

Mocking the service client at the service client level

Mocking a service client using the following code ...

Mocking the service_client
with mock.patch(
    "prowler.providers.<provider>.lib.audit_info.audit_info.audit_info",
    new=audit_info,
), mock.patch(
    "prowler.providers.<provider>.services.<service>.<check>.<check>.<service>_client",
    new=<SERVICE>(audit_info),
):
will cause that the service will be initialised twice:

  1. When the <SERVICE>(audit_info) is mocked out using mock.patch to have the object ready for the patching.
  2. At the <service>_client.py when we are patching it since the mock.patch needs to go to that object an initialise it, hence the <SERVICE>(audit_info) will be called again.

Then, when we import the <service>_client.py at <check>.py, since we are mocking where the object is used, Python will use the mocked one.

In the next section you will see an improved version to mock objects.

Mocking the service and the service client at the service client level

Mocking a service client using the following code ...

Mocking the service and the service_client
with mock.patch(
    "prowler.providers.<provider>.lib.audit_info.audit_info.audit_info",
    new=audit_info,
), mock.patch(
    "prowler.providers.<provider>.services.<service>.<SERVICE>",
    new=<SERVICE>(audit_info),
) as service_client, mock.patch(
    "prowler.providers.<provider>.services.<service>.<service>_client.<service>_client",
    new=service_client,
):
will cause that the service will be initialised once, just when the <SERVICE>(audit_info) is mocked out using mock.patch.

Then, at the check_level when Python tries to import the client with from prowler.providers.<provider>.services.<service>.<service>_client, since it is already mocked out, the execution will continue using the service_client without getting into the <service>_client.py.

Services

For testing the AWS services we have to follow the same logic as with the AWS checks, we have to check if the AWS API calls made by the service are covered by Moto and we have to test the service __init__ to verifiy that the information is being correctly retrieved.

The service tests could act as Integration Tests since we test how the service retrieves the information from the provider, but since Moto or the custom mock objects mocks that calls this test will fall into Unit Tests.

Please refer to the AWS checks tests for more information on how to create tests and check the existing services tests here.

GCP

Checks

For the GCP Provider we don't have any library to mock out the API calls we use. So in this scenario we inject the objects in the service client using MagicMock.

The following code shows how to use MagicMock to create the service objects for a GCP check test.

# We need to import the unittest.mock to allow us to patch some objects
# not to use shared ones between test, hence to isolate the test
from unittest import mock

# GCP Constants
GCP_PROJECT_ID = "123456789012"

# We are going to create a test for the compute_firewall_rdp_access_from_the_internet_allowed check
class Test_compute_firewall_rdp_access_from_the_internet_allowed:

    # We name the tests with test_<service>_<check_name>_<test_action>
    def test_compute_compute_firewall_rdp_access_from_the_internet_allowed_one_compliant_rule_with_valid_port(self):
        # Mocked client with MagicMock
        compute_client = mock.MagicMock

        # Assign GCP client configuration
        compute_client.project_ids = [GCP_PROJECT_ID]
        compute_client.region = "global"

        # Import the service resource model to create the mocked object
        from prowler.providers.gcp.services.compute.compute_service import Firewall

        # Create the custom Firewall object to be tested
        firewall = Firewall(
            name="test",
            id="1234567890",
            source_ranges=["0.0.0.0/0"],
            direction="INGRESS",
            allowed_rules=[{"IPProtocol": "tcp", "ports": ["443"]}],
            project_id=GCP_PROJECT_ID,
        )
        compute_client.firewalls = [firewall]

        # In this scenario we have to mock also the Compute service and the compute_client from the check to enforce that the compute_client used is the one created within this check because patch != import, and if you execute tests in parallel some objects can be already initialised hence the check won't be isolated.
        # In this case we don't use the Moto decorator, we use the mocked Compute client for both objects
        with mock.patch(
            "prowler.providers.gcp.services.compute.compute_service.Compute",
            new=defender_client,
        ), mock.patch(
            "prowler.providers.gcp.services.compute.compute_client.compute_client",
            new=defender_client,
        ):

            # We import the check within the two mocks not to initialise the iam_client with some shared information from
            # the current_audit_info or the Compute service.
            from prowler.providers.gcp.services.compute.compute_firewall_rdp_access_from_the_internet_allowed.compute_firewall_rdp_access_from_the_internet_allowed import (
                compute_firewall_rdp_access_from_the_internet_allowed,
            )

            # Once imported, we only need to instantiate the check's class
            check = compute_firewall_rdp_access_from_the_internet_allowed()

            # And then, call the execute() function to run the check
            # against the IAM client we've set up.
            result = check.execute()

            # Last but not least, we need to assert all the fields
            # from the check's results
            assert len(result) == 1
            assert result[0].status == "PASS"
            assert result[0].status_extended == f"Firewall {firewall.name} does not expose port 3389 (RDP) to the internet."
            assert result[0].resource_name = firewall.name
            assert result[0].resource_id == firewall.id
            assert result[0].project_id = GCP_PROJECT_ID
            assert result[0].location = compute_client.region

Services

Coming soon ...

Azure

Checks

For the Azure Provider we don't have any library to mock out the API calls we use. So in this scenario we inject the objects in the service client using MagicMock.

The following code shows how to use MagicMock to create the service objects for a Azure check test.

# We need to import the unittest.mock to allow us to patch some objects
# not to use shared ones between test, hence to isolate the test
from unittest import mock

from uuid import uuid4

# Azure Constants
from tests.providers.azure.azure_fixtures import AZURE_SUBSCRIPTION



# We are going to create a test for the Test_defender_ensure_defender_for_arm_is_on check
class Test_defender_ensure_defender_for_arm_is_on:

    # We name the tests with test_<service>_<check_name>_<test_action>
    def test_defender_defender_ensure_defender_for_arm_is_on_arm_pricing_tier_not_standard(self):
        resource_id = str(uuid4())

        # Mocked client with MagicMock
        defender_client = mock.MagicMock

        # Import the service resource model to create the mocked object
        from prowler.providers.azure.services.defender.defender_service import Defender_Pricing

        # Create the custom Defender object to be tested
        defender_client.pricings = {
            AZURE_SUBSCRIPTION: {
                "Arm": Defender_Pricing(
                    resource_id=resource_id,
                    pricing_tier="Not Standard",
                    free_trial_remaining_time=0,
                )
            }
        }

        # In this scenario we have to mock also the Defender service and the defender_client from the check to enforce that the defender_client used is the one created within this check because patch != import, and if you execute tests in parallel some objects can be already initialised hence the check won't be isolated.
        # In this case we don't use the Moto decorator, we use the mocked Defender client for both objects
        with mock.patch(
            "prowler.providers.azure.services.defender.defender_service.Defender",
            new=defender_client,
        ), mock.patch(
            "prowler.providers.azure.services.defender.defender_client.defender_client",
            new=defender_client,
        ):

            # We import the check within the two mocks not to initialise the iam_client with some shared information from
            # the current_audit_info or the Defender service.
            from prowler.providers.azure.services.defender.defender_ensure_defender_for_arm_is_on.defender_ensure_defender_for_arm_is_on import (
                defender_ensure_defender_for_arm_is_on,
            )

            # Once imported, we only need to instantiate the check's class
            check = defender_ensure_defender_for_arm_is_on()

            # And then, call the execute() function to run the check
            # against the IAM client we've set up.
            result = check.execute()

            # Last but not least, we need to assert all the fields
            # from the check's results
            assert len(result) == 1
            assert result[0].status == "FAIL"
            assert (
                result[0].status_extended
                == f"Defender plan Defender for ARM from subscription {AZURE_SUBSCRIPTION} is set to OFF (pricing tier not standard)"
            )
            assert result[0].subscription == AZURE_SUBSCRIPTION
            assert result[0].resource_name == "Defender plan ARM"
            assert result[0].resource_id == resource_id

Services

Coming soon ...