docs/contributing/testing.md - third_party/perfetto - Git at Google


            
            # Testing


            The testing strategy for Perfetto is rather complex due to the wide variety

            
            of build configurations and embedding targets.


            Common test targets (all platforms / checkouts):


            `perfetto_unittests`:

            
            Platform-agnostic unit-tests.


            `perfetto_integrationtests`:

            
            End-to-end tests, involving the protobuf-based IPC transport and ftrace

            
            integration (Linux/Android only).


            `perfetto_benchmarks`:

            
            Benchmarks tracking the performance of: (i) trace writing, (ii) trace readback

            
            and (iii) ftrace raw pipe -> protobuf translation.


            ## Running tests


            ### On Linux / MacOS


            ```bash

            
            tools/ninja -C out/default perfetto_{unittests,integrationtests,benchmarks}

            
            out/default/perfetto_unittests --gtest_help

            
            ```


            `perfetto_integrationtests` requires that the ftrace debugfs directory is

            
            is readable/writable by the current user on Linux:


            ```bash

            
            sudo chown  -R $USER /sys/kernel/debug/tracing

            
            ```


            ### On Android


            1.  Connect a device through `adb`

            
            2.  Start the build-in emulator (supported on Linux and MacOS):


            ```bash

            
            tools/install-build-deps --android

            
            tools/run_android_emulator &

            
            ```


            3. Run the tests (either on the emulator or physical device):


            ```bash

            
            tools/run_android_test out/default perfetto_unittests

            
            ```


            ## Continuous testing


            Perfetto is tested in a variety of locations:


            **Perfetto CI**: https://ci.perfetto.dev/

            
            Builds and runs perfetto\_{unittests,integrationtests,benchmarks} from the

            
            standalone checkout. Benchmarks are ran in a reduced form for smoke testing.

            
            See [this doc](/docs/design-docs/continuous-integration.md) for more details.


            **Android CI** (see go/apct and go/apct-guide):

            
            runs only `perfetto_integrationtests`


            **Android presubmits (TreeHugger)**:

            
            Runs before submission of every AOSP CL of `external/perfetto`.


            **Android CTS** (Android test suite used run to ensure API compatibility):

            
            Rolling runs internally.


            Note that Perfetto CI uses the standalone build system and the others build as

            
            part of the Android tree.


            ## Unit tests


            Unit tests exist for most of the code in Perfetto on the class level. They

            
            ensure that each class broadly works as expected.


            Unit tests are currently ran on ci.perfetto.dev and build.chromium.org.

            
            Running unit tests on APCT and Treehugger is WIP.


            ## Integration tests


            Integration tests ensure that subsystems (importantly ftrace and the IPC layer)

            
            and Perfetto as a whole is working correctly end-to-end.


            There are two configurations in which integration tests can be run:


            **1. Production mode** (Android-only)

            
            This mode assumes that both the tracing service (`traced`) and the OS probes

            
            service (`traced_probes`) are already running. In this mode the test enables

            
            only the consumer endpoint and tests the interaction with the production

            
            services. This is the way our Android CTS and APCT tests work.


            **2. Standalone mode**:

            
            Starting up the daemons in the test itself and then testing against them.

            
            This is how standalone builds are tested. This is the only supported way to

            
            run integration tests on Linux and MacOS.


            ## Trace Processor diff tests


            Trace processor is mainly tested using so called "diff tests".


            For these tests, trace processor parses a known trace and executes a query

            
            string or file. The output of these queries is then compared (i.e. "diff"ed) against

            
            an expected output file and discrepencies are highlighted.


            Similar diff tests are also available when writing metrics - instead of a

            
            query, the metric name is used and the expected output string contains

            
            the expected result of computing the metric.


            These tests (for both queries and metrics) can be run as follows:


            ```bash

            
            tools/ninja -C <out directory>

            
            tools/diff_test_trace_processor.py <out directory>/trace_processor_shell

            
            ```


            TIP: Query diff tests are expected to only have a single query which produces

            
            output in the whole file (usually at the end). Calling

            
            `SELECT RUN_METRIC('metric file')` can trip up this check as this query

            
            generates some hidden output. To address this issue, if a query only has

            
            column is named `suppress_query_output`, even if it has output, this will

            
            be ignored (for example,

            
            `SELECT RUN_METRIC('metric file') as suppress_query_output`)


            ## UI pixel diff tests


            The pixel tests are used to ensure core user journeys work by verifying they

            
            are the same pixel to pixel against a golden screenshot. They use a headless

            
            chrome to load the webpage and take a screenshot and compare pixel by pixel a

            
            golden screenshot. You can run these tests by using `ui/run-integrationtests`.


            These test fail when a certain number of pixels are different. If these tests

            
            fail, you'll need to investigate the diff and determine if its intentional. If

            
            its a desired change you will need to update the screenshots on a linux machine

            
            to get the CI to pass. You can update them by generating and uploading a new

            
            baseline (this requires access to a google bucket through gcloud which only

            
            googlers have access to, googlers can install gcloud

            
            [here](https://g3doc.corp.google.com/cloud/sdk/g3doc/index.md#installing-and-using-the-cloud-sdk)).


            The tests are run in a docker container by default, unless -`-no-docker` is

            
            passed. It's recommended to use the container for a stable and reproducable

            
            testing environment, especially for rebaselining, otherwise it's very likely the

            
            screenshots will not match when run on the CI.


            ```

            
            ui/run-integrationtests --rebaseline

            
            tools/test_data upload

            
            ```


            Once finished you can commit and upload as part of your CL to cause the CI to

            
            use your new screenshots.


            NOTE: If you see a failing diff test you can see the pixel differences on the CI

            
            by using a link ending with `ui-test-artifacts/index.html`. Report located on

            
            that page contains changed screenshots as well as a command to accept the

            
            changes if these are desirable.


            ## Android CTS tests


            CTS tests ensure that any vendors who modify Android remain compliant with the

            
            platform API.


            These tests include a subset of the integration tests above as well as adding

            
            more complex tests which ensure interaction between platform (e.g. Android apps

            
            etc.) and Perfetto is not broken.


            The relevant targets are `CtsPerfettoProducerApp` and `CtsPerfettoTestCases`. Once these are built, the following commands should be run:


            ```bash

            
            adb push $ANDROID_HOST_OUT/cts/android-cts/testcases/CtsPerfettoTestCases64 /data/local/tmp/

            
            adb install -r $ANDROID_HOST_OUT/cts/android-cts/testcases/CtsPerfettoProducerApp.apk

            
            ```


            Next, the app named `android.perfetto.producer` should be run on the device.


            Finally, the following command should be run:


            ```bash

            
            adb shell /data/local/tmp/CtsPerfettoTestCases64

            
            ```


            ## {#chromium} Chromium waterfall


            Perfetto is constantly rolled into chromium's //third_party/perfetto via

            
            [this autoroller](https://autoroll.skia.org/r/perfetto-chromium-autoroll).


            The [Chromium CI](https://build.chromium.org) runs the `perfetto_unittests`

            
            target, as defined in the [buildbot config][chromium_buildbot].


            You can also test a pending Perfetto CL against Chromium's CI / TryBots

            
            before submitting it. This can be useful when making trickier API changes or to

            
            test on platforms that the Perfetto CI doesn't cover (e.g. Windows, MacOS),

            
            allowing you to verify the patch before you submit it (and it then eventually

            
            auto-rolls into Chromium).


            To do this, first make sure you have uploaded pull request to GitHub.

            
            Next, create a new Chromium CL that modifies Chromium's

            
            `//src/DEPS` file.


            If you recently uploaded your change, it may be enough to modify the git commit

            
            hash in the `DEPS` entry for `src/third_party/perfetto`:


            ```

            
              'src/third_party/perfetto':

            
                Var('chromium_git') + '/external/github.com/google/perfetto/' + '@' + '8fe19f55468ee227e99c1a682bd8c0e8f7e5bcdb',

            
            ```


            Replace the git hash with the commit hash of your most recent patch set.


            Alternatively, you can add `hooks` to patch in the pending CL on top of

            
            Chromium's current third_party/perfetto revision. For this, add the following

            
            entries to the `hooks` array in Chromium's `//src/DEPS` file, modifying the

            
            `refs/pull/XXXX/head` to the appropriate values for your pull request.


            ```

            
              {

            
                'name': 'fetch_custom_patch',

            
                'pattern': '.',

            
                'action': [ 'git', '-C', 'src/third_party/perfetto/',

            
                            'fetch', 'https://github.com/google/perfetto.git',

            
                            'refs/pull/XXXX/head',

            
                ],

            
              },

            
              {

            
                'name': 'apply_custom_patch',

            
                'pattern': '.',

            
                'action': ['git', '-C', 'src/third_party/perfetto/',

            
                           '-c', 'user.name=Custom Patch', '-c', 'user.email=custompatch@example.com',

            
                           'cherry-pick', 'FETCH_HEAD',

            
                ],

            
              },

            
            ```


            If you'd like to test your change against the SDK build of Chrome, you

            
            can add `Cq-Include-Trybots:` lines for perfetto SDK trybots to the change

            
            description in gerrit (this won't be needed once Chrome's migration to the

            
            SDK is complete, see [tracking bug][sdk_migration_bug]):


            ```

            
            Cq-Include-Trybots: luci.chromium.try:linux-perfetto-rel

            
            Cq-Include-Trybots: luci.chromium.try:android-perfetto-rel

            
            Cq-Include-Trybots: luci.chromium.try:mac-perfetto-rel

            
            Cq-Include-Trybots: luci.chromium.try:win-perfetto-rel

            
            ```


            [chromium_buildbot]: https://cs.chromium.org/search/?q=perfetto_.*tests+f:%5Esrc/testing.*json$&sq=package:chromium&type=cs

            
            [chromium_cl]: https://chromium-review.googlesource.com/c/chromium/src/+/2030528

            
            [sdk_migration_bug]: https://crbug.com/1006541
	# Testing

	The testing strategy for Perfetto is rather complex due to the wide variety
	of build configurations and embedding targets.

	Common test targets (all platforms / checkouts):

	`perfetto_unittests`:
	Platform-agnostic unit-tests.

	`perfetto_integrationtests`:
	End-to-end tests, involving the protobuf-based IPC transport and ftrace
	integration (Linux/Android only).

	`perfetto_benchmarks`:
	Benchmarks tracking the performance of: (i) trace writing, (ii) trace readback
	and (iii) ftrace raw pipe -> protobuf translation.

	## Running tests

	### On Linux / MacOS

	```bash
	tools/ninja -C out/default perfetto_{unittests,integrationtests,benchmarks}
	out/default/perfetto_unittests --gtest_help
	```

	`perfetto_integrationtests` requires that the ftrace debugfs directory is
	is readable/writable by the current user on Linux:

	```bash
	sudo chown -R $USER /sys/kernel/debug/tracing
	```

	### On Android

	1. Connect a device through `adb`
	2. Start the build-in emulator (supported on Linux and MacOS):

	```bash
	tools/install-build-deps --android
	tools/run_android_emulator &
	```

	3. Run the tests (either on the emulator or physical device):

	```bash
	tools/run_android_test out/default perfetto_unittests
	```

	## Continuous testing

	Perfetto is tested in a variety of locations:

	Perfetto CI: https://ci.perfetto.dev/
	Builds and runs perfetto\_{unittests,integrationtests,benchmarks} from the
	standalone checkout. Benchmarks are ran in a reduced form for smoke testing.
	See [this doc](/docs/design-docs/continuous-integration.md) for more details.

	Android CI (see go/apct and go/apct-guide):
	runs only `perfetto_integrationtests`

	Android presubmits (TreeHugger):
	Runs before submission of every AOSP CL of `external/perfetto`.

	Android CTS (Android test suite used run to ensure API compatibility):
	Rolling runs internally.

	Note that Perfetto CI uses the standalone build system and the others build as
	part of the Android tree.

	## Unit tests

	Unit tests exist for most of the code in Perfetto on the class level. They
	ensure that each class broadly works as expected.

	Unit tests are currently ran on ci.perfetto.dev and build.chromium.org.
	Running unit tests on APCT and Treehugger is WIP.

	## Integration tests

	Integration tests ensure that subsystems (importantly ftrace and the IPC layer)
	and Perfetto as a whole is working correctly end-to-end.

	There are two configurations in which integration tests can be run:

	1. Production mode (Android-only)
	This mode assumes that both the tracing service (`traced`) and the OS probes
	service (`traced_probes`) are already running. In this mode the test enables
	only the consumer endpoint and tests the interaction with the production
	services. This is the way our Android CTS and APCT tests work.

	2. Standalone mode:
	Starting up the daemons in the test itself and then testing against them.
	This is how standalone builds are tested. This is the only supported way to
	run integration tests on Linux and MacOS.

	## Trace Processor diff tests

	Trace processor is mainly tested using so called "diff tests".

	For these tests, trace processor parses a known trace and executes a query
	string or file. The output of these queries is then compared (i.e. "diff"ed) against
	an expected output file and discrepencies are highlighted.

	Similar diff tests are also available when writing metrics - instead of a
	query, the metric name is used and the expected output string contains
	the expected result of computing the metric.

	These tests (for both queries and metrics) can be run as follows:

	```bash
	tools/ninja -C <out directory>
	tools/diff_test_trace_processor.py <out directory>/trace_processor_shell
	```

	TIP: Query diff tests are expected to only have a single query which produces
	output in the whole file (usually at the end). Calling
	`SELECT RUN_METRIC('metric file')` can trip up this check as this query
	generates some hidden output. To address this issue, if a query only has
	column is named `suppress_query_output`, even if it has output, this will
	be ignored (for example,
	`SELECT RUN_METRIC('metric file') as suppress_query_output`)

	## UI pixel diff tests

	The pixel tests are used to ensure core user journeys work by verifying they
	are the same pixel to pixel against a golden screenshot. They use a headless
	chrome to load the webpage and take a screenshot and compare pixel by pixel a
	golden screenshot. You can run these tests by using `ui/run-integrationtests`.

	These test fail when a certain number of pixels are different. If these tests
	fail, you'll need to investigate the diff and determine if its intentional. If
	its a desired change you will need to update the screenshots on a linux machine
	to get the CI to pass. You can update them by generating and uploading a new
	baseline (this requires access to a google bucket through gcloud which only
	googlers have access to, googlers can install gcloud
	[here](https://g3doc.corp.google.com/cloud/sdk/g3doc/index.md#installing-and-using-the-cloud-sdk)).

	The tests are run in a docker container by default, unless -`-no-docker` is
	passed. It's recommended to use the container for a stable and reproducable
	testing environment, especially for rebaselining, otherwise it's very likely the
	screenshots will not match when run on the CI.

	```
	ui/run-integrationtests --rebaseline
	tools/test_data upload
	```

	Once finished you can commit and upload as part of your CL to cause the CI to
	use your new screenshots.

	NOTE: If you see a failing diff test you can see the pixel differences on the CI
	by using a link ending with `ui-test-artifacts/index.html`. Report located on
	that page contains changed screenshots as well as a command to accept the
	changes if these are desirable.

	## Android CTS tests

	CTS tests ensure that any vendors who modify Android remain compliant with the
	platform API.

	These tests include a subset of the integration tests above as well as adding
	more complex tests which ensure interaction between platform (e.g. Android apps
	etc.) and Perfetto is not broken.

	The relevant targets are `CtsPerfettoProducerApp` and `CtsPerfettoTestCases`. Once these are built, the following commands should be run:

	```bash
	adb push $ANDROID_HOST_OUT/cts/android-cts/testcases/CtsPerfettoTestCases64 /data/local/tmp/
	adb install -r $ANDROID_HOST_OUT/cts/android-cts/testcases/CtsPerfettoProducerApp.apk
	```

	Next, the app named `android.perfetto.producer` should be run on the device.

	Finally, the following command should be run:

	```bash
	adb shell /data/local/tmp/CtsPerfettoTestCases64
	```

	## {#chromium} Chromium waterfall

	Perfetto is constantly rolled into chromium's //third_party/perfetto via
	[this autoroller](https://autoroll.skia.org/r/perfetto-chromium-autoroll).

	The [Chromium CI](https://build.chromium.org) runs the `perfetto_unittests`
	target, as defined in the [buildbot config][chromium_buildbot].

	You can also test a pending Perfetto CL against Chromium's CI / TryBots
	before submitting it. This can be useful when making trickier API changes or to
	test on platforms that the Perfetto CI doesn't cover (e.g. Windows, MacOS),
	allowing you to verify the patch before you submit it (and it then eventually
	auto-rolls into Chromium).

	To do this, first make sure you have uploaded pull request to GitHub.
	Next, create a new Chromium CL that modifies Chromium's
	`//src/DEPS` file.

	If you recently uploaded your change, it may be enough to modify the git commit
	hash in the `DEPS` entry for `src/third_party/perfetto`:

	```
	'src/third_party/perfetto':
	Var('chromium_git') + '/external/github.com/google/perfetto/' + '@' + '8fe19f55468ee227e99c1a682bd8c0e8f7e5bcdb',
	```

	Replace the git hash with the commit hash of your most recent patch set.

	Alternatively, you can add `hooks` to patch in the pending CL on top of
	Chromium's current third_party/perfetto revision. For this, add the following
	entries to the `hooks` array in Chromium's `//src/DEPS` file, modifying the
	`refs/pull/XXXX/head` to the appropriate values for your pull request.

	```
	{
	'name': 'fetch_custom_patch',
	'pattern': '.',
	'action': [ 'git', '-C', 'src/third_party/perfetto/',
	'fetch', 'https://github.com/google/perfetto.git',
	'refs/pull/XXXX/head',
	],
	},
	{
	'name': 'apply_custom_patch',
	'pattern': '.',
	'action': ['git', '-C', 'src/third_party/perfetto/',
	'-c', 'user.name=Custom Patch', '-c', 'user.email=custompatch@example.com',
	'cherry-pick', 'FETCH_HEAD',
	],
	},
	```

	If you'd like to test your change against the SDK build of Chrome, you
	can add `Cq-Include-Trybots:` lines for perfetto SDK trybots to the change
	description in gerrit (this won't be needed once Chrome's migration to the
	SDK is complete, see [tracking bug][sdk_migration_bug]):

	```
	Cq-Include-Trybots: luci.chromium.try:linux-perfetto-rel
	Cq-Include-Trybots: luci.chromium.try:android-perfetto-rel
	Cq-Include-Trybots: luci.chromium.try:mac-perfetto-rel
	Cq-Include-Trybots: luci.chromium.try:win-perfetto-rel
	```

	[chromium_buildbot]: https://cs.chromium.org/search/?q=perfetto_.tests+f:%5Esrc/testing.json$&sq=package:chromium&type=cs
	[chromium_cl]: https://chromium-review.googlesource.com/c/chromium/src/+/2030528
	[sdk_migration_bug]: https://crbug.com/1006541