Cucumber is BDD framework which works for iOS, Android and more. For Android, we are going to use cucumber-jvm, java port of cucumber.

BDD's behavior text is written in a business-readable domain-specific language. It aims to communicate better between non-tech to tech over Software trueness and quality.
The readable behavior also serves as documentation.

Gherkin plugin works with Android Studio 2.0. Manual translation is still required but .feature file has pretty syntax highlighting and any invalid cucumber syntax will be flagged with an error.

Install Plugin: Android Studio > Preferences > Plugins > Search "Gherkin" > Install & Restart Android Studio

1. Add dependencies

   androidTestCompile 'com.android.support.test.espresso:espresso-core:2.0'
   androidTestCompile 'com.android.support.test:testing-support-lib:0.1'
   androidTestCompile 'info.cukes:cucumber-android:1.2.0@jar'
   androidTestCompile 'info.cukes:cucumber-picocontainer:1.2.0'
   

2. Create custom instrumentation runner under androidTest package

   public class Instrumentation extends MonitoringInstrumentation {
   
     private final CucumberInstrumentationCore mInstrumentationCore = new CucumberInstrumentationCore(this);
   
     @Override
     public void onCreate(Bundle arguments) {
       super.onCreate(arguments);
   
       mInstrumentationCore.create(arguments);
       start();
     }
   
     @Override
     public void onStart() {
       super.onStart();
   
       waitForIdleSync();
       mInstrumentationCore.start();
     }
   }

3. Application ID / Runner setup in app/build.gradle. Make sure this matches with the package name of the test.

   testApplicationId "com.emmasuzuki.cucumberespressodemo.test"
   testInstrumentationRunner "com.emmasuzuki.cucumberespressodemo.test.Instrumentation"
   

4. Create assets/features directory under androidTest. This directory holds behavior(.feature) files.

5. Set assets directory in app/build.gradle.

   android {
       ...
       sourceSets {
           androidTest {
               assets.srcDirs = ['src/androidTest/assets']
           }
       }
   }
   

Make a file, login.feature, and put under src/androidTest/assets/features.

```
Feature: Login
Perform login on email and password are inputted

  Scenario Outline: Input email and password in correct format
    Given I have a LoginActivity
    When I input email <email>
    And I input password "<password>"
    And I press submit button
    Then I should <see> auth error

  Examples:
    | email              | password   | see   |
    | [email protected] | bananacake | true  |
    | [email protected] | lemoncake  | false |     <-- valid email and password
    | [email protected]    | lemoncake  | true  |
```

EX) 
"Given I have a LoginActivity" in behavior translates to
    
@Given("^I have a LoginActivity")
public void I_have_a_LoginActivity(){}
    
in step definition
    
"Then I should see error on the <view>" in behavior translates to
    
@Then("^I should see error on the (\\S+)$")
public void I_should_see_error_on_the_editTextView(final String viewName) {}

@When("^I input email (\\S+)$")
public void I_input_email(final String email) {
    onView(withId(R.id.email)).perform(typeText(email));
}
    
@Then("^I should (true|false) auth error$")
public void I_should_see_auth_error(boolean shouldSeeError) {
    if (shouldSeeError) {
        onView(withId(R.id.error)).check(matches(isDisplayed()));
    } else {
        onView(withId(R.id.error)).check(matches(not(isDisplayed())));
    }
}

On command line, run with $./gradlew connectedCheck

On Android Studio, take the following steps:

1. Run > Edit Configurations
2. Click "+" on left pane
3. Select Android Tests
4. Put any name at Name:
5. Select "app" for module
6. Add the created custom runner for specific instrumentation runner
7. Hit Apply
8. Choose the craeted Run configuration
9. Click Run

Write code and run test again. Observe the tests pass.

Please feel free to contact me at [email protected]