compiler/src/it/unused-provider-methods-fail-compilation/verify.bsh

import dagger.testing.it.BuildLogValidator;
import java.io.File;

File buildLog = new File(basedir, "build.log");
new BuildLogValidator().assertHasText(buildLog, new String[]{
    "You have these unused @Provider methods:",
    "1. test.TestModule.string()",
    "Set library=true in your module to disable this check."
    });