Create a job in junkins and (configure the adb path) add this command to create steps as a shell execution command or as a bat cmd window
$ adb shell am instrument -w com.xyz.abc.test/android.test.InstrumentationTestRunner
PS: - For better automation, use a robotium and a spoon with junkins, you can automate everything, you click commit on git and you will get test results in your inbox, which will be cool.
Edit
Running tests using a spoon
Add these commands to create steps.
./gradlew assembleDebugAndroidTest ./gradlew assembleDebug
specify the path debug-build.apk and test-unaligned.apk the path in the correct spoon
java -jar C:\Users\Shivam\Downloads\spoon-runner-1.1.1-jar-with-dependencies.jar --apk C:\Users\Shivam\Downloads\SpoonAndRobotiumTest\app\build\outputs\ apk\app-debug.apk --testapk C:\Users\Shivam\Downloads\SpoonAndRobotiumTest\ app\build\outputs\apk\app-debug androidTest-unaligned.apk --sdk E:\sdk
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