Unable to find instrumentation info for: ComponentInfo{}

I am having trouble running Junit test case in Android. Running any test, starts the emulator and gives this: Running tests Test running startedTest running failed: Unable to find instrumentation info for: ComponentInfo{http://ift.tt/1LpOstG} Empty test suite.

<manifest xmlns:android="http://ift.tt/nIICcg"
      package="com.example.android.app"
      android:versionCode="1"
      android:versionName="1.0">
<uses-sdk android:minSdkVersion="8"/>

<application>
    <uses-library android:name="android.test.runner"/>
</application>

<instrumentation android:name="android.test.InstrumentationTestRunner"
                 android:targetPackage="com.example.android.app"
                 android:label="Tests for com.example.android.app"/>

</manifest>