Travis CI — A beginner tutorial

If you have ever contributed to open source , You must have seen few things.

1. Build passes
2. Travis failed

Have you ever tried to know the reason behind these messages ? If answer is NO , you’re definitely reading the right post!

Understanding the Travis.yml file

Let’s take it step by step!

1. sudo requirement is added because a license needs to be manually added later.
2. In line 2 & 3 , we’re specifying that project will be built in the Android environment & use jdk8.
3. In line 6–10 , it is the list of Android SDK components to be installed.
4. In line 11–12 , executable permission is provided to gradlew
5. In line 13–14, it is the gradle buildcommand along with stacktrace

Yayyy!

Some more detailed configuration

• To avoid uploading the cache after every build, travis.yml might contain these lines :

before_cache:
  - rm -f  $HOME/.gradle/caches/modules-2/modules-2.lock
  - rm -fr $HOME/.gradle/caches/*/plugin-resolution/
cache:
  directories:
    - $HOME/.gradle/caches/
    - $HOME/.gradle/wrapper/
    - $HOME/.android/build-cache

• Creating an android emulator :

before_script:
- echo no | android create avd --force -n test -t android-21 --abi armeabi-v7a
- emulator -avd test -no-skin -no-audio -no-window &
- android-wait-for-emulator
- adb shell input keyevent 82 &

• To run instrumentation tests (src/androidTests), we can add connectedCheck in script block.

Understanding the common build error

• There is always good probability that your PR changes are not valid & gradle build actually fails. To solve it , Re-build your application & then check whether gradle builds successfully.
• Some organisation might have enabled the travis integration but yml file might be absent & it can give you error.

• Travis might be overdoing the work & timeout may occur.

• Include these lines in your gradle file :

lintOptions {
    abortOnError false
}

If it’s not present then the build will fail if there is a lint error in the project.

That’s all! Please do clap, comment(reviews or doubts) and Share it :)

May the Code be with you all ❤