Using test-variant string resources in espresso tests

build.gradle

def buildConfigAndResStringField(variant, name, value) {
    variant.resValue 'string', name.toLowerCase(), value
    variant.buildConfigField 'String', name, "\"$value\""
}

// Tried this, tests use the .debug suffix, not the .debug.test suffix
afterEvaluate {
    android.applicationVariants.each { variant ->
        buildConfigAndResStringField variant, "ACCOUNT_TYPE", variant.applicationId
        buildConfigAndResStringField variant, "TOKEN_TYPE", variant.applicationId
        buildConfigAndResStringField variant, "CONTENT_AUTHORITY", variant.applicationId + ".provider"

        if (variant.testVariant != null) {
            System.out.println("testVariant ${variant.applicationId}")
            buildConfigAndResStringField variant.testVariant, "ACCOUNT_TYPE", variant.applicationId + ".test"
            buildConfigAndResStringField variant.testVariant, "TOKEN_TYPE", variant.applicationId + ".test"
            buildConfigAndResStringField variant.testVariant, "CONTENT_AUTHORITY", variant.applicationId + ".provider.test"
        }
    }
}

// Also tried this, tests use the .debug suffix, not the .debug.test suffix
afterEvaluate {
    android.applicationVariants.each { variant ->
        buildConfigAndResStringField variant, "ACCOUNT_TYPE", variant.applicationId
        buildConfigAndResStringField variant, "TOKEN_TYPE", variant.applicationId
        buildConfigAndResStringField variant, "CONTENT_AUTHORITY", variant.applicationId + ".provider"
    }

    android.testVariants.each { variant ->
        System.out.println("testVariant ${variant.applicationId}")
        buildConfigAndResStringField variant, "ACCOUNT_TYPE", variant.applicationId + ".test"
        buildConfigAndResStringField variant, "TOKEN_TYPE", variant.applicationId + ".test"
        buildConfigAndResStringField variant, "CONTENT_AUTHORITY", variant.applicationId + ".provider.test"
    }
}

// Question is, how can I get the app to use the `.test` version of the resource string
// when running InstrumentationTests?