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Effective in 2026, to align with our trunk stable development model and ensure platform stability for the ecosystem, we will publish source code to AOSP in Q2 and Q4. For building and contributing to AOSP, use android-latest-release. The android-latest-release manifest branch will always reference the most recent release pushed to AOSP. For more information, see Changes to AOSP.
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The Android Compatibility Program
is the key driver to sustain the positive feedback for Android ecosystem. CTS
is the key tool to ensure the quality of compatibility in the scale. The
Android team continues to improve CTS tool and test coverage. The regular
addition of test cases has significant improvement on the quality of
compatible devices.
General questions
This section provides general CTS FAQs.
What kinds of things does the CTS test?
The CTS tests that all of the supported Android strong-typed APIs
are present and behave correctly. The CTS also tests other non-API system
behaviors such as app lifecycle and performance.
How is the CTS licensed?
The CTS is licensed under the same Apache Software License 2.0 that the
bulk of Android uses.
Are codecs verified by CTS?
Yes. All mandatory codecs are verified by CTS.
Test-specific questions
This section provides FAQs that help run CTS tests more efficiently.
What is the difference between CTS Sharding and TF Sharding?
CTS Sharding and TF Sharding are totally different test plans powered by
different test infrastructure codebase. While the run command is the
same across different versions, the sharding result behaves differently.
CTS Sharding statically assigns test cases to Devices Under Test (DUTs)
as follows:
Command: run cts
Configuration for Android 8.1 and lower versions:
/tools/cts-tradefed/res/config/cts.xml
TF Sharding dynamically assigns test cases to available DUTs as follows:
Command: run cts
Configuration for Android 9:
/platform/test/suite_harness/+/pie-cts-dev/tools/cts-tradefed/res/config/cts-suite.xml
What is expected from a device supporting multiple ABIs?
The device has to pass all CTS and CTS Verifier tests for each ABI mode it
claims to support. Therefore, it is necessary to execute an app for the
particular ABIs. The guidelines for multiple ABIs are as follows:
For CTS and CTS Verifier, there are
ARM and x86 releases for
each architecture. Each of them can support to 32- or 64-bit mode.
For CTS tests, if a device supports both ARM and x86, it has to run
and pass both ARM and x86 CTS tests respectively.
See CDD 3.3.1. Application Binary Interfaces
for CDD requirements on ABI.
Is it sufficient to run a test only on the primary ABI (for example, 64 bits) to reduce test execution time?
No. An Android app runs on its own 32 -bit or 64-bit runtimes.
The actual machine code, code path, and state are different
between 32 and 64. If you skip one mode, you are only covering 50% of
the device ABI.
Why are there so many test cases reported as Not Executed?
You should check the Module Done number instead
of Not Executed number.
In the previous versions, CTS modules were reported as Module Done too
aggressively before being completed. Therefore, a Modules Done number
was reported without all the test case complete even when some devices
had problems. The new test harness is more conservative and reports a
higher number of Not Executed tests when a problem occurs.
A module run to completion reports Module Not Done in the most
recent invocation (done="false") in the report during the following:
A test run for the module was interrupted by a device connection issue.
Not all expected test runs for the module were performed.
Retried (using option -r/--retry) with additional filtering options,
such as:
--include-filter
--exclude-filter
-t/--test (Option not yet supported on retry)
--retry-type failed
--subplan
To obtain a status of Module Done (done="true") for these modules,
retry the following for the most recent invocation:
run retry --retry <session_id> for Android 9 and later versions
run cts --retry <session_id> for Android 8.1 and previous versions
A module executed without any of the problems mentioned previously (even
with 0 remaining tests) is marked Module Done in the new report.
Exceptions
CtsNNAPITestCases has a known issue due to linux/OS limitation of args.
The module can be rerun in isolation through run cts -m
CtsNNAPITestCases directly.
How can I avoid test preparation failing behind corporate firewall?
All automated test suites try to download either the CTS media files or the
business logic files during runtime. In many corporate environments, a
firewall and proxy is typical, which makes the test preparation fail. Execute
the following line or add it to .profile (on Ubuntu).
export JAVA_TOOL_OPTIONS='-Djava.net.useSystemProxies=true'
Do I need a SIM card for CTS for Secure Element?
Whether a SIM card is needed for the test depends on the understanding
if the feature is supported in the test device.
If your device DOES NOT need to support the Android apps accessing
secure elements—either in the
UICC
(e.g., a SIM card) distributed by the mobile network operators
(carriers) or embedded in the device—you can configure the HIDL
manifest to not include the android.hardware.secure_element HAL
element. In this case, the
android.se.omapi.SEService.getReaders()
API reports an empty list and the CTS test automatically
passes and reports a pass for the CTS.
If your device DOES need to support Android apps accessing either
secure elements—either in the UICC
(e.g., a SIM card) distributed by the mobile network operators (carriers) or
embedded in the device—you need to implement secure element properly
and test it in-house. CTS Test for Secure Element
outlines how to prepare to run the CTS tests that ensure
android.se.omapi
API package added in Android 9 is functional. We also recommend
performing additional testing on your own since the CTS test coverage
is minimal.
Where can I get the SIM cards for CTS for Secure Element?
You can reach out to your preferred SIM vendor.
Why is Orange SIM on the lock screen during CTS execution with token sharding?
The test case doesn't start because testing the SIM card is locked.
Disable the Lock SIM card in **SIM card lock settings before
executing the CTS with token sharding.
Test runs when the feature flags are disabled in the device
For all flags in the release builds, the
@RequiresFlagsEnabled or @RequiresFlagsDisabled annotation uses the values
of the flags from the CTS binary release config, not from the device release
config. Disabling the flags on the device doesn't disable the test as the set
of CTS tests that run for a given release is fixed to the AOSP platform
released config.
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 2026-06-17 UTC.
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