Upgrading to API 22 breaks test suite

Question

I am attempting to upgrade an existing project to compile with and target API 22. I changed the following lines in my build.gradle:

android {
    compileSdkVersion 22
...

    defaultConfig {
...
        targetSdkVersion 22
    }
...
dependencies {
...
    compile 'com.android.support:appcompat-v7:22.2.0'
    compile 'com.android.support:support-v4:22.2.0'
...
    }
}

Note that these are the only changes in the entire project. Now suddenly, many of my tests fail. All of the failing tests use Robotium and call solo.clickOnActionBarItem(). However, the button on the action bar never seems to be clicked. When I watch the test running, I do not see the expected behavior from the button click.

What are the reasons for the failure of solo.clickOnActionBarItem() to not click an action bar item? More importantly, how can I figure out what the problem is when it appears to be something in a third-party library I am using?