Python framework tests

The python test framework is built on top of the ChipDeviceCtrl.py python controller API and the Mobly test framework. Python tests are interaction tests, and can be used for certification testing, and / or integration testing in the CI.

Python tests located in src/python_testing

Resources for getting started

Writing Python tests

  • Defining arguments in the test script
    • In order to streamline the configuration and execution of tests, it is essential to define arguments at the top of the test script. This section should include various parameters and their respective values, which will guide the test runner on how to execute the tests.
  • All test classes inherit from MatterBaseTest in matter_testing_support.py
    • Support for commissioning using the python controller
    • Default controller (self.default_controller) of type ChipDeviceCtrl
    • MatterBaseTest inherits from the Mobly BaseTestClass
  • Test method(s) (start with test_) and are all run automatically
    • To run in the test harness, the test method name must be test_TC_PICSCODE_#_#
      • More information about integration with the test harness can be found in Test Harness helpers section
    • Any tests that use async method (read / write / commands) should be decorated with the @async_test_body decorator
  • Use ChipDeviceCtrl to interact with the DUT
    • Controller API is in ChipDeviceCtrl.py (see API doc in file)
    • Some support methods in matter_testing_support.py
  • Use Mobly assertions for failing tests
  • self.step() along with a steps_* method to mark test plan steps for cert tests

A simple test

# See https://github.com/project-chip/connectedhomeip/blob/master/docs/testing/python.md#defining-the-ci-test-arguments
# for details about the block below.
#
# === BEGIN CI TEST ARGUMENTS ===
# test-runner-runs:
#   run1:
#     app: ${ALL_CLUSTERS_APP}
#     app-args: --discriminator 1234 --KVS kvs1 --trace-to json:${TRACE_APP}.json
#     script-args: >
#       --storage-path admin_storage.json
#       --commissioning-method on-network
#       --discriminator 1234
#       --passcode 20202021
#       --trace-to json:${TRACE_TEST_JSON}.json
#       --trace-to perfetto:${TRACE_TEST_PERFETTO}.perfetto
#     factory-reset: true
#     quiet: true
# === END CI TEST ARGUMENTS ===

class TC_MYTEST_1_1(MatterBaseTest):

    @async_test_body
    async def test_TC_MYTEST_1_1(self):

        vendor_name = await self.read_single_attribute_check_success(
            dev_ctrl=self.default_controller, <span style="color:#38761D"># defaults to
self.default_controlller</span>
            node_id = self.dut_node_id, <span style="color:#38761D"># defaults to
self.dut_node_id</span>
            cluster=Clusters.BasicInformation,
            attribute=Clusters.BasicInformation.Attributes.VendorName,
            endpoint = 0, <span style="color:#38761D">#defaults to 0</span>
        )
        asserts.assert_equal(vendor_name, “Test vendor name”, “Unexpected vendor name”)

if __name__ == "__main__":
default_matter_test_main()

In this test, asserts.assert_equal is used to fail the test on equality assertion failure (throws an exception).

Because the test requires the use of the async method read_single_attribute_check_success, the test is decorated with the @async_test_body decorator

The default_matter_test_main() function is used to run the test on the command line. These two lines should appear verbatim at the bottom of every python test file.

The structured comments above the class definition are used to set up the CI for the tests. Please see Running tests in CI.

Cluster Codegen

Common import used in test files: import chip.clusters as Clusters

Each cluster is defined in the Clusters.<ClusterName> namespace and contains always:

  • id
  • descriptor

Each Clusters.<ClusterName> will include the appropriate sub-classes (if defined for the cluster):

  • Enums
  • Bitmaps
  • Structs
  • Attributes
  • Commands
  • Events

Attributes

Attributes derive from ClusterAttributeDescriptor

Each Clusters.<ClusterName>.Attributes.<AttributeName> class has:

  • cluster_id
  • attribute_id
  • attribute_type
  • value

Example:

  • class - Clusters.OnOff.Attributes.OnTime
    • Used for Read commands
  • instance - Clusters.OnOff.Attributes.OnTime(5)
    • Sets the value to 5
    • Pass the instance to Write method to write the value

Commands

Commands derive from ClusterCommand.

Each Clusters.<ClusterName>.Commands.<CommandName> class has:

  • cluster_id
  • command_id
  • is_client
  • response_type (None for status response)
  • descriptor
  • data members (if required)

Example:

  • Clusters.OnOff.Commands.OnWithTimedOff(onOffControl=0, onTime=5, offWaitTime=8)
  • Clusters.OnOff.Commands.OnWithTimedOff()
    • Command with no fields

Events

Events derive from ClusterEvent.

Each Clusters.<ClusterName>.Events.<EventName> class has:

  • cluster_id
  • event_id
  • descriptor
  • Other data members if required

Example:

  • Clusters.AccessControl.Events.AccessControlEntryChanged.adminNodeID

Enums

Enums derive from MatterIntEnum.

Each Clusters.<ClusterName>.Enum.<EnumName> has

  • k<value> constants
  • kUnknownEnumValue (used for testing, do not transmit)

Example:

  • Clusters.AccessControl.Enums.AccessControlEntryPrivilegeEnum.kAdminister

Bitmaps

Bitmaps derive from IntFlag

Each Clusters.<ClusterName>.Bitmaps.<BitmapName> has: - k

Special class:

  • class Feature(IntFlag) - contains the feature map bitmaps

Example:

  • Clusters.LaundryWasherControls.Bitmaps.Feature.kSpin

Structs

Structs derive from ClusterObject.

Each Clusters.<ClusterName>.Structs.<StructName> has:

  • A “descriptor”
  • Data members

Example:

Clusters.BasicInformation.Structs.ProductAppearanceStruct(
   finish=Clusters.BasicInformation.Enums.ProductFinishEnum.kFabric,
   primaryColor=Clusters.BasicInformation.Enums.ColorEnum.kBlack)

Accessing Clusters and Cluster Elements by ID

ClusterObjects.py has a set of objects that map ID to the code generated object.

chip.clusters.ClusterObjects.ALL_CLUSTERS

  • dict[int, Cluster] - maps cluster ID to Cluster class
    • cluster = chip.clusters.ClusterObjects.ALL_CLUSTERS[cluster_id]

chip.clusters.ClusterObjects.ALL_ATTRIBUTES

  • dict[int, dict[int, ClusterAttributeDescriptor]] - maps cluster ID to a dict of attribute ID to attribute class
    • attr = chip.clusters.ClusterObjects.ALL_ATTRIBUTES[cluster_id][attribute_id]

chip.clusters.ClusterObjects.ALL_ACCEPTED_COMMANDS/ALL_GENERATED_COMMANDS

  • dict[int, dict[int, ClusterCommand]]
  • cmd = chip.clusters.ClusterObjects.ALL_ACCEPTED_COMMANDS[cluster_id][cmd_id]

ChipDeviceCtrl API

The ChipDeviceCtrl API is implemented in ChipDeviceCtrl.py.

The ChipDeviceCtrl implements a python-based controller that can be used to commission and control devices. The API is documented here in the ChipDeviceCtrl API documentation

The API doc gives full descriptions of the APIs being used. The most commonly used methods are linked below.

Read

  • Read both attributes and events
  • Can handle wildcard or concrete path

ReadAttribute

  • Convenience wrapper for Read for attributes

Examples: Wildcard read (all clusters, all endpoints):

await dev_ctrl.ReadAttribute(node_id, [()])

Wildcard read (single endpoint 0)

await dev_ctrl.ReadAttribute(node_id, [(0)])

Wildcard read (single cluster from single endpoint 0)

await dev_ctrl.ReadAttribute(node_id, [(1, Clusters.OnOff)])

Single attribute

await dev_ctrl.ReadAttribute(node_id, [(1, Clusters.OnOff.Attributes.OnTime)])

Multi-path

await dev_ctrl.ReadAttribute(node_id, [(1, Clusters.OnOff.Attributes.OnTime),(1, Clusters.OnOff.Attributes.OnOff)])

ReadEvent

  • Convenience wrapper for Read
  • Similar to ReadAttribute, but the tuple includes urgency as the last argument

Example:

urgent = 1

await dev_ctrl ReadEvent(node_id, [(1,
Clusters.TimeSynchronization.Events.MissingTrustedTimeSource, urgent)])

Subscriptions

Subscriptions are handled in the Read / ReadAttribute / ReadEvent APIs. To initiate a subscription, set the reportInterval tuple argument to set the floor and ceiling. The keepSubscriptions and autoResubscribe arguments also apply to subscriptions.

Subscription return ClusterAttribute.SubscriptionTransaction. This can be used to set callbacks. The object is returned after the priming data read is complete, and the values there are used to populate the cache. The attribute callbacks are called on update.

  • SetAttributeUpdateCallback
    • Callable[[TypedAttributePath, SubscriptionTransaction], None]
  • SetEventUpdateCallback
    • Callable[[EventReadResult, SubscriptionTransaction], None]
  • await changes in the main loop using a trigger mechanism from the callback.

Example for setting callbacks:

q = queue.Queue()
cb = SimpleEventCallback("cb", cluster_id, event_id, q)

urgent = 1
subscription = await dev_ctrl.ReadEvent(nodeid=1, events=[(1, event, urgent)], reportInterval=[1, 3])
subscription.SetEventUpdateCallback(callback=cb)

try:
    q.get(block=True, timeout=timeout)
except queue.Empty:
    asserts.assert_fail(“Timeout on event”)

WriteAttribute

Handles concrete paths only (per spec), can handle lists. Returns list of PyChipError

  • Instantiate the ClusterAttributeDescriptor class with the value you want to send, tuple is (endpoint, attribute)
    • use timedRequestTimeoutMs for timed request actions

Example:

res = await devCtrl.WriteAttribute(nodeid=0, attributes=[(0,Clusters.BasicInformation.Attributes.NodeLabel("Test"))])
asserts.assert_equal(ret[0].status, Status.Success, “write failed”)

SendCommand

  • Instantiate the command object with the values you need to populate
  • If there is a non-status return, it’s returned from the command
  • If there is a pure status return it will return nothing
  • Raises InteractionModelError on failure

Example:

pai = await dev_ctrl.SendCommand(nodeid, 0, Clusters.OperationalCredentials.Commands.CertificateChainRequest(2))

MatterBaseTest helpers

  • Because we tend to do a lot of single read / single commands in tests, we added a couple of helpers in MatterBaseTest that use some of the default values
    • read_single_attribute_check_success()
    • read_single_attribute_expect_error()
    • send_single_cmd()
  • step() method to mark step progress for the test harness
  • skip() / skip_step() / skip_remaining_steps() methods for test harness integration
  • check_pics() / pics_guard() to handle pics

Mobly helpers

The test system is based on Mobly, and the matter_testing_support.py class provides some helpers for Mobly integration.

  • default_matter_test_main
    • Sets up commissioning and finds all tests, parses command-line arguments

use as:

if __name__ == "__main__":
    default_matter_test_main()
  • Mobly will run all methods starting with test_ prefix by default
    • use --tests command line argument to specify exact name,s
  • Setup and teardown methods
    • setup_class / teardown_class
    • setup_test / teardown_test
    • Don’t forget to call the super() if you override these

Test harness helpers

The python testing system also includes several methods for integrations with the test harness. To integrate with the test harness, you can define the following methods on your class to allow the test harness UI to properly work through your tests.

All of these methods are demonstrated in the hello_example.py reference.

  • Steps enumeration:
    • Define a method called steps_<YourTestMethodName> to allow the test harness to display the steps
    • Use the self.step(<stepnum>) method to walk through the steps
  • Test description:
    • Define a method called desc_<YourTestMethodName> to send back a string with the test description
  • Top-level PICS:
    • To guard your test on a top level PICS, define a method called pics_<YourTestMethodName> to send back a list of PICS. If this method is omitted, the test will be run for every endpoint on every device.
  • Overriding the default timeout:
    • If the test is exceptionally long running, define a property getter method default_timeout to adjust the timeout. The default is 90 seconds.

Deferred failures: For some tests, it makes sense to perform the entire test before failing and collect all the errors so the developers can address all the failures without needing to re-run the test multiple times. For example, tests that look at every attribute on the cluster and perform independent operations on them etc.

For such tests, use the ProblemNotice format and the convenience methods:

  • self.record_error
  • self.record_warning

These methods keep track of the problems, and will print them at the end of the test. The test will not be failed until an assert is called.

A good example of this type of test can be found in the device basic composition tests, where all the test steps are independent and performed on a single read. See Device Basic Composition tests

Command line arguments

  • Use --help to get a full list
  • --storage-path
    • Used to set a local storage file path for persisted data to avoid clashing files. It is suggested to always provide this argument. Default value is admin_storage.json in current directory.
  • --commissioning-method
    • Need to re-commission to python controller as chip-tool and python commissioner do not share a credentials
  • --discriminator, --passcode, --qr-code, --manual-code
  • --tests to select tests
  • --PICS
  • --int-arg, --bool-arg, --float-arg, --string-arg, --json-arg, --hex-arg
    • Specify as key:value ex --bool-arg pixit_name:False
    • Used for custom arguments to scripts (PIXITs)

PICS and PIXITS

  • PICS
    • use --PICS on the command line to specify the PICS file
    • use check_pics to gate steps in a file
  • have_whatever = check_pics(“PICS.S.WHATEVER”)
  • PIXITs
    • use --int-arg, --bool-arg etc on the command line to specify PIXITs
    • Warn users if they don’t set required values, add instructions in the comments
  • pixit_value = self.user_params.get(“pixit_name”, default)

Support functionality

To create a controller on a new fabric:

new_CA = self.certificate_authority_manager.NewCertificateAuthority()

new_fabric_admin = new_certificate_authority.NewFabricAdmin(vendorId=0xFFF1,
    fabricId=self.matter_test_config.fabric_id + 1)

TH2 = new_fabric_admin.NewController(nodeId=112233)

Open a commissioning window (ECW):

params = self.OpenCommissioningWindow(dev_ctrl=self.default_controller, node_id=self.dut_node_id)

To create a new controller on the SAME fabric, allocate a new controller from the fabric admin.

Fabric admin for default controller:

  fa = self.certificate_authority_manager.activeCaList[0].adminList[0]
  second_ctrl = fa.new_fabric_admin.NewController(nodeId=node_id)

Automating manual steps

Some test plans have manual steps that require the tester to manually change the state of the DUT. To run these tests in a CI environment, specific example apps can be built such that these manual steps can be achieved by Matter or named-pipe commands.

In the case that all the manual steps in a test script can be achieved just using Matter commands, you can check if the PICS_SDK_CI_ONLY PICS is set to decide if the test script should send the required Matter commands to perform the manual step.

self.is_ci = self.check_pics("PICS_SDK_CI_ONLY")

In the case that a test script requires the use of named-pipe commands to achieve the manual steps, you can use the write_to_app_pipe(command) to send these commands. This command requires the test class to define a self.app_pipe string value with the name of the pipe. This depends on how the app is set up.

If the name of the pipe is dynamic and based on the app's PID, the following snippet can be added to the start of tests that use the write_to_app_pipe method.

app_pid = self.matter_test_config.app_pid
if app_pid != 0:
	self.is_ci = true
	self.app_pipe = "/tmp/chip_<app name>_fifo_" + str(app_pid)

This requires the test to be executed with the --app-pid flag set if the manual steps should be executed by the script. This flag sets the process ID of the DUT's matter application.

Running on a separate machines

If the DUT and test script are running on different machines, the write_to_app_pipe method can send named-pipe commands to the DUT via ssh. This requires two additional environment variables:

  • LINUX_DUT_IP sets the DUT's IP address
  • LINUX_DUT_UNAME sets the DUT's ssh username. If not set, this is assumed to be root.

The write_to_app_pipe also requires that ssh-keys are set up to access the DUT from the machine running the test script without a password. You can follow these steps to set this up:

  1. If you do not have a key, create one using ssh-keygen.
  2. Authorize this key on the remote host: run ssh-copy-id user@ip once, using your password.
  3. From now on ssh user@ip will no longer ask for your password.

Other support utilities

  • basic_composition_support
    • wildcard read, whole device analysis
  • CommissioningFlowBlocks
    • various commissioning support for core tests
  • spec_parsing_support
    • parsing data model XML into python readable format

Running tests locally

Setup

The scripts require the python wheel to be compiled and installed before running. To compile and install the wheel, do the following:

First activate the matter environment using either

. ./scripts/bootstrap.sh

or

. ./scripts/activate.sh

bootstrap.sh should be used for for the first setup, activate.sh may be used for subsequent setups as it is faster.

Next build the python wheels and create / activate a venv (called pyenv here, but any name may be used)

./scripts/build_python.sh -i out/python_env
source pyenv/bin/activate

Running tests

  • Note that devices must be commissioned by the python test harness to run tests. chip-tool and the python test harness DO NOT share a fabric.

Once the wheel is installed, you can run the python script as a normal python file for local testing against an already-running DUT. This can be an example app on the host computer (running in a different terminal), or a separate device that will be commissioned either over BLE or WiFi.

For example, to run the TC-ACE-1.2 tests against an un-commissioned DUT:

python3 src/python_testing/TC_ACE_1_2.py --commissioning-method on-network --qr-code MT:-24J0AFN00KA0648G00

Some tests require additional arguments (ex. PIXITs or configuration variables for the CI). These arguments can be passed as sets of key/value pairs using the --<type>-arg:<value> command line arguments. For example:

--int-arg PIXIT.ACE.APPENDPOINT:1 --int-arg PIXIT.ACE.APPDEVTYPEID:0x0100 --string-arg PIXIT.ACE.APPCLUSTER:OnOff --string-arg PIXIT.ACE.APPATTRIBUTE:OnOff

Local host app testing

./scripts/tests/run_python_test.py is a convenient script that starts an example DUT on the host and includes factory reset support

./scripts/tests/run_python_test.py --factory-reset --app <your_app> --app-args "whatever" --script <your_script> --script-args "whatever"

Running tests in CI

  • Add test to the repl_tests_linux section of .github/workflows/tests.yaml
  • Don’t forget to set the PICS file to the ci-pics-values
  • If there are steps in your test that will fail on CI (e.g. test vendor checks), gate them on the PICS_SDK_CI_ONLY
    • if not self.is_pics_sdk_ci_only:
    ...  # Step that will fail on CI

The CI test runner uses a structured environment setup that can be declared using structured comments at the top of the test file. To use this structured format, use the --load-from-env flag with the run_python_tests.py runner.

Ex: scripts/run_in_python_env.sh out/venv './scripts/tests/run_python_test.py --load-from-env /tmp/test_env.yaml --script src/python_testing/TC_ICDM_2_1.py'

Running ALL or a subset of tests when changing application code

scripts/tests/local.py is a wrapper that is able to build and run tests in a single command.

Example to compile all prerequisites and then running all python tests:

./scripts/tests/local.py build         # will compile python in out/pyenv and ALL application prerequisites
./scripts/tests/local.py python-tests  # Runs all python tests that are runnable in CI

Defining the CI test arguments

Arguments required to run a test can be defined in the comment block at the top of the test script. The section with the arguments should be placed between the # === BEGIN CI TEST ARGUMENTS === and # === END CI TEST ARGUMENTS === markers. Arguments should be structured as a valid YAML dictionary with a root key test-runner-runs, followed by the run identifier, and then the parameters for that run, e.g.:

# See https://github.com/project-chip/connectedhomeip/blob/master/docs/testing/python.md#defining-the-ci-test-arguments
# for details about the block below.
#
# === BEGIN CI TEST ARGUMENTS ===
# test-runner-runs:
#   run1:
#     app: ${TYPE_OF_APP}
#     app-args: <app_arguments>
#     script-args: <script_arguments>
#     factory-reset: <true|false>
#     quiet: <true|false>
# === END CI TEST ARGUMENTS ===

Description of Parameters

  • app: Indicates the application to be used in the test. Different app types as needed could be referenced from section [name: Generate an argument environment file ] of the file .github/workflows/tests.yaml

    • Example: ${TYPE_OF_APP}

  • factory-reset: Determines whether a factory reset should be performed before the test.

    • Example: true

  • quiet: Sets the verbosity level of the test run. When set to True, the test run will be quieter.

    • Example: true

  • app-args: Specifies the arguments to be passed to the application during the test.

    • Example: --discriminator 1234 --KVS kvs1 --trace-to json:${TRACE_APP}.json

  • app-ready-pattern: Regular expression pattern to match against the output of the application to determine when the application is ready. If this parameter is specified, the test runner will not run the test script until the pattern is found.

    • Example: "Manual pairing code: \\[\\d+\\]"

  • script-args: Specifies the arguments to be passed to the test script.

    • Example: --storage-path admin_storage.json --commissioning-method on-network --discriminator 1234 --passcode 20202021 --trace-to json:${TRACE_TEST_JSON}.json --trace-to perfetto:${TRACE_TEST_PERFETTO}.perfetto

This structured format ensures that all necessary configurations are clearly defined and easily understood, allowing for consistent and reliable test execution.