CTS largely operates via adb. There's a whole lot of functionality available in `adb shell` that's largely to support the CTS. So, CTS has access as `adb shell` and as the many apps it installs, including device managers, accessibility services, etc. that it authorizes.
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CTS is kind of unprivileged and does most of the testing via apps, but it also does a whole lot of stuff via `adb shell` that an app could never do, and it uses `adb shell` to install the thousands of different app-based test suites, etc.
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If you look at the CTS modules list, you'll see a lot of modules with the term "Host" in their name, and that means a test suite that operates via `adb shell` and largely does the work on the host running the CTS test harness, not within an app on the device like most tests.
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To fully pass the CTS, you need to have a non-test-key-signed release / user build. Something that amuses me is that the public CTS build published by Google isn't signed with release keys and it gets mad about the apps it sees using the test key that it installed itself.
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Can build it from source and properly sign it or just ignore those couple test failures though.
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grapheneos.org/build#compatib has a quick guide on using their public builds. In the CTS test harness, `run cts --skip-device-info --module CtsBackupTestCases` will run the backup tests.
Those definitely pass on a user build and it does backups/restores via LocalTransport.
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right, I'm reading the CTS sources right now but so far I don't understand how it actually pulls/pushes the data
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I think it's a set of app-based test suites that are installed and run on the device rather than host tests, and it just triggers LocalTransport via adb and then does most of the work via the code running on the device. I'm normally just running the CTS tests, not writing them.
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android.googlesource.com/platform/cts/+ is the metadata telling the CTS test harness what to do including the app-based test suites to install and run together. In many cases it cheats via adb tricks like granting minor 'development' permissions that must be granted via adb shell.
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I *think* that test suite never actually pulls any data to the host? it just uses a lot of apks to exercise the transport, and matches logcat messages for what it can't do that way
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Yeah, they'd probably have it marked as a host test if it needed to run non-trivial code on the host. I assumed these were host tests and that it fetched the data but they're just normal app-based tests.