Android Base64 encode and decode return null in Unit Test

Question

I am attempting to decode a Base64 encoded string in Android using the http://developer.android.com/reference/android/util/Base64.html class.

Both the encodeToString and

Answer 1

As discussed, android.util.Base64.decode is returning a null in test harness because of this setting in the build file:

testOptions {
    unitTests.returnDefaultValues = true
}

To avoid including other libraries you could fall back on java.util.Base64, which is only available in Java8 and on Android 26 and above. If you already target 26+ then just switch to this method, but if you have to target earlier SDKs you could check for the null return and call a test-harness method instead:

// Required because Android classes return null in desktop unit tests
@TargetApi(26)
private fun testHarnessDecode(s : String) : ByteArray {
    return java.util.Base64.getDecoder().decode(s)
}

I would rather do this than pull in additional library dependencies, but YMMV.