Run a sample App Percy build with Espresso

Clone the sample application

Clone the sample application and install the required dependencies:

Upload app

Upload Testsuite

Create an App Percy project

Sign in to Percy and create a new app project, for example, test-project. After you’ve created the project, you’ll be shown a Percy Access Token. Use it in the next step.

Set Percy token as an environment variable

Export the token environment variable:

To set the project token as an environment variable, include the PERCY_TOKEN in the curl command as shown in step 5.

Generate the first build

Check out a new branch for your work in this tutorial (we’ll call this branch tutorial-example), then run tests & take screenshots:

For the App Automate session to work with App Percy, we need to provide App Percy parameters.

For instance, in “appPercy”: {“env”: {“PERCY_BRANCH”: “test”}, “PERCY_TOKEN”: “"}, the env parameter can contain any of the following Percy environment variables.

Execute tests using the following command post updating App Percy parameters:

This will run the application Espresso tests present in the Java example file, where the appPercy.screenshot command is called. The captured screenshots will then be uploaded to Percy for comparison.

Modify the sample application

Let’s introduce a visual change and generate the second build to understand App Percy’s visual testing capability. Here we have updated the example application Java file “EnsureInputTests.java” by updating the resource id in the ensureSingleInputIsHandled test to R.id.buttonTwo. You can directly use testSuite_2 from the resources folder.
Note: We’ve only simulated a visual change in this instance.

Commit your changes

Create a commit with the changes.

Run tests again

Run the tests with screenshots again.

• Follow Step 2 to upload testSuite_2 to App Automate.

• Follow Step 5 to run the test.

The new screenshots are uploaded to Percy and compared with the previous screenshots, showing visual differences.

View visual differences on dashboard

Visit your project in Percy and you’ll see a new build with visual comparisons between the two runs. Click anywhere on the Build 2 row (we are assuming here that you are using a new project to test things out). You can see the original screenshots on the left, and the new screenshots on the right.

Percy has highlighted what’s changed visually in the app! Screenshots with the largest changes are shown first You can click on the highlight to reveal the underlying screenshot.

If you scroll down, you’ll see that no other test cases were impacted by our changes to text. The unchanged screenshots are shown under an Unchanged filter and are hidden by default.