Create methods to avoid knowing the ID of the ViewPager if there's on…

…ly one ViewPager (#58)

* Test that avoiding passing the R.id.pager also works when there are just one ViewPager

* Implement the solution to the tests

* Introduce new methods on the README.md

* Add Javadoc to clarify the automation of the added methods

* Add a custom matcher for diplayed views assignable from a given class

* Use the new matcher method and reorder methods to meet the newspaper metaphor

* Fix an infinite loop due to a bad copy paste (thanks, FindBugs!)

* Improve a parameter name to offer a better API

README.md

@@ -52,7 +52,9 @@ clickDialogNegativeButton();
 // Scroll on scrolls and pagers
 scrollTo(R.id.button);
 scrollTo("A widget with this text");
+swipeViewPagerForward();
 swipeViewPagerForward(R.id.pager);
+swipeViewPagerBack();
 swipeViewPagerBack(R.id.pager);
 
 // Interact with the navigation drawer

library/build.gradle

@@ -31,6 +31,8 @@ dependencies {
     }
     compile 'com.android.support.test.uiautomator:uiautomator-v18:2.1.2'
     compile 'com.android.support:support-annotations:25.1.0'
+    compile 'com.android.support:support-core-ui:25.1.0'
+
     testCompile 'junit:junit:4.12'
     testCompile 'org.assertj:assertj-core:1.7.0'
 }

library/src/main/java/com/schibsted/spain/barista/BaristaViewPagerActions.java

@@ -1,18 +1,40 @@
 package com.schibsted.spain.barista;
 
 import android.support.annotation.IdRes;
+import android.support.v4.view.ViewPager;
 
 import static android.support.test.espresso.Espresso.onView;
 import static android.support.test.espresso.action.ViewActions.swipeLeft;
 import static android.support.test.espresso.action.ViewActions.swipeRight;
+import static com.schibsted.spain.barista.custom.DisplayedMatchers.displayedAssignableFrom;
 import static com.schibsted.spain.barista.custom.DisplayedMatchers.displayedWithId;
 
 public class BaristaViewPagerActions {
 
+  /*
+   * Finds a ViewPager and swipes it forward.
+   *
+   * It only works if there's only one ViewPager displayed on the screen.
+   * If there are more than one, use swipeViewPagerForward(@IdRes int id)
+   */
+  public static void swipeViewPagerForward() {
+    onView(displayedAssignableFrom(ViewPager.class)).perform(swipeLeft());
+  }
+
   public static void swipeViewPagerForward(@IdRes int id) {
     onView(displayedWithId(id)).perform(swipeLeft());
   }
 
+  /*
+   * Finds a ViewPager and swipes it back.
+   *
+   * It only works if there's only one ViewPager displayed on the screen.
+   * If there are more than one, use swipeViewPagerBack(@IdRes int id)
+   */
+  public static void swipeViewPagerBack() {
+    onView(displayedAssignableFrom(ViewPager.class)).perform(swipeRight());
+  }
+
   public static void swipeViewPagerBack(@IdRes int id) {
     onView(displayedWithId(id)).perform(swipeRight());
   }

library/src/main/java/com/schibsted/spain/barista/custom/DisplayedMatchers.java

@@ -4,9 +4,9 @@
 import android.support.annotation.NonNull;
 import android.support.annotation.StringRes;
 import android.view.View;
-
 import org.hamcrest.Matcher;
 
+import static android.support.test.espresso.matcher.ViewMatchers.isAssignableFrom;
 import static android.support.test.espresso.matcher.ViewMatchers.isDisplayed;
 import static android.support.test.espresso.matcher.ViewMatchers.withId;
 import static android.support.test.espresso.matcher.ViewMatchers.withText;
@@ -28,4 +28,9 @@ public static Matcher<View> displayedWithText(@StringRes int text) {
   public static Matcher<View> displayedWithText(String text) {
     return allOf(isDisplayed(), withText(text));
   }
+
+  @NonNull
+  public static Matcher<View> displayedAssignableFrom(final Class<? extends View> viewClass) {
+    return allOf(isDisplayed(), isAssignableFrom(viewClass));
+  }
 }

sample/src/androidTest/java/com/schibsted/spain/barista/sample/ViewPagerWithoutIdTest.java

@@ -0,0 +1,49 @@
+package com.schibsted.spain.barista.sample;
+
+import android.support.test.runner.AndroidJUnit4;
+import com.schibsted.spain.barista.flakyespresso.FlakyActivityTestRule;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import static com.schibsted.spain.barista.BaristaAssertions.assertDisplayed;
+import static com.schibsted.spain.barista.BaristaViewPagerActions.swipeViewPagerBack;
+import static com.schibsted.spain.barista.BaristaViewPagerActions.swipeViewPagerForward;
+
+@RunWith(AndroidJUnit4.class)
+public class ViewPagerWithoutIdTest {
+
+  @Rule
+  public FlakyActivityTestRule<ViewPagerActivity> activityRule = new FlakyActivityTestRule<>(ViewPagerActivity.class)
+      .allowFlakyAttemptsByDefault(10);
+
+  @Test
+  public void checkSwipeForward() {
+    swipeViewPagerForward();
+
+    assertDisplayed("2");
+  }
+
+  @Test
+  public void checkSwipeBack() {
+    swipeViewPagerForward();
+    swipeViewPagerBack();
+
+    assertDisplayed("1");
+  }
+
+  @Test
+  public void swipingBackInTheFirstPageDoesntCrash() {
+    swipeViewPagerBack();
+
+    assertDisplayed("1");
+  }
+
+  @Test
+  public void swipingForwardInTheLastPageDoesntCrash() {
+    swipeViewPagerForward();
+    swipeViewPagerForward();
+
+    assertDisplayed("2");
+  }
+}

sample/src/androidTest/java/com/schibsted/spain/barista/sample/introduction/IntroducingBaristaActions.java

@@ -75,7 +75,9 @@ public void letsIntroduceBarista() {
     // Scroll on scrolls and pagers
     scrollTo(R.id.button);
     scrollTo("A widget with this text");
+    swipeViewPagerForward();
     swipeViewPagerForward(R.id.pager);
+    swipeViewPagerBack();
     swipeViewPagerBack(R.id.pager);
 
     // Interact with the navigation drawer