Starting March 27, 2025, we recommend using android-latest-release instead of aosp-main to build and contribute to AOSP. For more information, see Changes to AOSP.
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Compatibility Test Suite (CTS) is a free, commercial-grade test suite and
tools used to help ensure that your devices are Android compatible. CTS is
intended to be integrated into your daily workflow, such as through a
continuous build system. CTS runs on a desktop machine and executes tests
directly on attached devices or on an emulator. For an overview of Android compatibility, see Android compatibility program overview.
Figure 1. CTS automated testing.
Figure 1 shows the process of executing CTS automated tests:
Download and install CTS. This step also involves setting up the test environment, the testing workstation, and the device you are testing or device under test (DUT)
Run CTS automated tests.
Store and review the results.
Troubleshoot issues and rerun tests.
Use CTS to reveal incompatibilities early, and to ensure that your Android
implementations remain compatible throughout the development process.
CTS components
CTS contains the following major components:
Trade Federation
A test harness and framework allow for the automated execution of tests.
CTS automated tests
Tests that use the Trade Federation framework and can be run using the Trade
Federation test harness.
CTS Verifier (CTS-V) tests
Tests that must be run manually.
CTS Verifier (CTS-V) app
An app used to conduct CTS-V tests and collect CTS-V test results.
Test case
An individual test executed on the DUT. Automated test cases are
written in Java as JUnit tests and packaged Android APK files to run on the
device target.
Test cases can be unit tests or functional tests. A unit test tests atomic
units of code within the Android platform. For example, a unit test might test
a single Android class.
A functional test exercises a combination of methods and classes used for a
specific use case.
Test configuration
A specific set of automated tests that are run on the
DUT. Test configurations are XML files located in
WORKING_DIRECTORY/cts/tools/cts-tradefed/res/config.
There are test configurations that contains all automated test cases and test
configurations that contain a subset of test cases.
Test module
A test configuration consisting of a collection of test cases for the same
feature area.
Test plan
A test configuration consisting of a collection of test modules.
Test coverage
Test cases cover the following areas to ensure compatibility:
Area
Description
Signature tests
For each Android release, there are XML files describing the signatures of all
public APIs contained in the release. The CTS contains a utility to check those API
signatures against the APIs available on the device. The results from signature
checking are recorded in the test result XML file.
Platform API tests
Test the platform (core libraries and Android Application Framework) APIs as documented
in the SDK Class Index to
ensure API correctness, including correct class, attribute and method signatures,
correct method behavior, and negative tests to ensure expected behavior for
incorrect parameter handling.
Dalvik tests
The tests focus on testing the Dalvik executable format.
Platform data model
The CTS tests the core platform data model as exposed to application developers
through content providers, as documented in the
SDK android.provider package (including contacts, browsers, and settings)
Platform intents
The CTS tests the core platform intents, as documented in the
SDK
Common intents.
Platform permissions
The CTS tests the core platform permissions, as documented in the
SDK Manifest.permission.
Platform resources
The CTS tests for correct handling of the core platform resource types,
as documented in the
SDK
Resource types overview. The CTS tests include tests for simple values, drawables, nine-patch,
animations, layouts, styles and themes, and loading alternate resources.
What's next
After reading this document, continue to Set up CTS.
Content and code samples on this page are subject to the licenses described in the Content License. Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.
Last updated 2025-06-12 UTC.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-06-12 UTC."],[],[],null,["# The Compatibility Test Suite (CTS) overview\n\n*Compatibility Test Suite (CTS)* is a free, commercial-grade test suite and\ntools used to help ensure that your devices are Android compatible. CTS is\nintended to be integrated into your daily workflow, such as through a\ncontinuous build system. CTS runs on a desktop machine and executes tests\ndirectly on attached devices or on an emulator. For an overview of Android compatibility, see [Android compatibility program overview](/docs/compatibility).\n\n**Figure 1.** CTS automated testing.\n\nFigure 1 shows the process of executing CTS automated tests:\n\n1. Download and install CTS. This step also involves setting up the test environment, the testing workstation, and the device you are testing or *device under test (DUT)*\n2. Run CTS automated tests.\n3. Store and review the results.\n4. Troubleshoot issues and rerun tests.\n\nUse CTS to reveal incompatibilities early, and to ensure that your Android\nimplementations remain compatible throughout the development process.\n\nCTS components\n--------------\n\nCTS contains the following major components:\n\n*Trade Federation*\n: A test harness and framework allow for the automated execution of tests.\n\n*CTS automated tests*\n: Tests that use the Trade Federation framework and can be run using the Trade\n Federation test harness.\n\n*CTS Verifier (CTS-V) tests*\n: Tests that must be run manually.\n\n*CTS Verifier (CTS-V) app*\n: An app used to conduct CTS-V tests and collect CTS-V test results.\n\n*Test case*\n\n: An individual test executed on the DUT. Automated test cases are\n written in Java as JUnit tests and packaged Android APK files to run on the\n device target.\n\n Test cases can be *unit tests* or *functional tests*. A unit test tests atomic\n units of code within the Android platform. For example, a unit test might test\n a single Android class.\n\n A functional test exercises a combination of methods and classes used for a\n specific use case.\n\n*Test configuration*\n\n: A specific set of automated tests that are run on the\n DUT. Test configurations are XML files located in\n \u003cvar translate=\"no\"\u003eWORKING_DIRECTORY\u003c/var\u003e`/cts/tools/cts-tradefed/res/config`.\n There are test configurations that contains all automated test cases and test\n configurations that contain a subset of test cases.\n\n*Test module*\n\n: A test configuration consisting of a collection of test cases for the same\n feature area.\n\n*Test plan*\n\n: A test configuration consisting of a collection of test modules.\n\n| **Note:** The Android Open Source Project accepts contributions to improve CTS just as for any other component. Improving the coverage and quality of CTS tests is one of the best ways to contribute to Android. To make contributions to CTS, follow the same process in [Submit code changes](/docs/setup/contribute/submit-patches).\n\nTest coverage\n-------------\n\nTest cases cover the following areas to ensure compatibility:\n\n| Area | Description |\n|----------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|\n| Signature tests | For each Android release, there are XML files describing the signatures of all public APIs contained in the release. The CTS contains a utility to check those API signatures against the APIs available on the device. The results from signature checking are recorded in the test result XML file. |\n| Platform API tests | Test the platform (core libraries and Android Application Framework) APIs as documented in the SDK [Class Index](https://developer.android.com/reference/classes) to ensure API correctness, including correct class, attribute and method signatures, correct method behavior, and negative tests to ensure expected behavior for incorrect parameter handling. |\n| Dalvik tests | The tests focus on testing the Dalvik executable format. |\n| Platform data model | The CTS tests the core platform data model as exposed to application developers through content providers, as documented in the SDK [`android.provider`](https://developer.android.com/reference/android/provider/package-summary) package (including contacts, browsers, and settings) |\n| Platform intents | The CTS tests the core platform intents, as documented in the SDK [Common intents](https://developer.android.com/guide/appendix/g-app-intents). |\n| Platform permissions | The CTS tests the core platform permissions, as documented in the SDK [`Manifest.permission`](https://developer.android.com/reference/android/Manifest.permission). |\n| Platform resources | The CTS tests for correct handling of the core platform resource types, as documented in the SDK [Resource types overview](https://developer.android.com/guide/topics/resources/available-resources). The CTS tests include tests for simple values, drawables, nine-patch, animations, layouts, styles and themes, and loading alternate resources. |\n\nWhat's next\n-----------\n\nAfter reading this document, continue to [Set up CTS](/docs/compatibility/cts/setup)."]]
