ViewMatchers.java

package com.google.android.apps.common.testing.ui.espresso.matcher;

import static com.google.android.apps.common.testing.ui.espresso.util.TreeIterables.breadthFirstViewTraversal;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;
import static org.hamcrest.Matchers.is;

import com.google.android.apps.common.testing.ui.espresso.util.HumanReadables;
import com.google.common.base.Predicate;
import com.google.common.collect.Iterables;

import android.content.res.Resources;
import android.graphics.Rect;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewParent;
import android.view.inputmethod.EditorInfo;
import android.view.inputmethod.InputConnection;
import android.widget.Checkable;
import android.widget.TextView;

import junit.framework.AssertionFailedError;

import org.hamcrest.Description;
import org.hamcrest.Matcher;
import org.hamcrest.Matchers;
import org.hamcrest.StringDescription;
import org.hamcrest.TypeSafeMatcher;

import java.util.Iterator;

/**
 * A collection of hamcrest matchers that match {@link View}s.
 */
public final class ViewMatchers {

  private ViewMatchers() {}

  /**
   * Returns a matcher that matches Views which are an instance of or subclass of the provided
   * class. Some versions of Hamcrest make the generic typing of this a nightmare, so we have a
   * special case for our users.
   */
  public static Matcher<View> isAssignableFrom(final Class<? extends View> clazz) {
    checkNotNull(clazz);
    return new TypeSafeMatcher<View>() {
      @Override
      public void describeTo(Description description) {
        description.appendText("is assignable from class: " + clazz);
      }

      @Override
      public boolean matchesSafely(View view) {
        return clazz.isAssignableFrom(view.getClass());
      }
    };
  }

 /**
   * Returns a matcher that matches Views with class name matching the given matcher.
   */
  public static Matcher<View> withClassName(final Matcher<String> classNameMatcher) {
    checkNotNull(classNameMatcher);
    return new TypeSafeMatcher<View>() {
      @Override
      public void describeTo(Description description) {
        description.appendText("with class name: ");
        classNameMatcher.describeTo(description);
      }

      @Override
      public boolean matchesSafely(View view) {
        return classNameMatcher.matches(view.getClass().getName());
      }
    };
  }

  /**
   * Returns a matcher that matches {@link View}s that are currently displayed on the screen to the
   * user.
   *
   * Note: isDisplayed will select views that are partially displayed (eg: the full height/width of
   * the view is greater then the height/width of the visible rectangle). If you wish to ensure the
   * entire rectangle this view draws is displayed to the user use isCompletelyDisplayed.
   */
  public static Matcher<View> isDisplayed() {
    return new TypeSafeMatcher<View>() {
      @Override
      public void describeTo(Description description) {
        description.appendText("is displayed on the screen to the user");
      }

      @Override
      public boolean matchesSafely(View view) {
        return view.getGlobalVisibleRect(new Rect()) &&
            withEffectiveVisibility(Visibility.VISIBLE).matches(view);
      }
    };
  }

  /**
   * Returns a matcher which only accepts a view whose height and width fit perfectly within
   * the currently displayed region of this view.
   *
   * There exist views (such as ScrollViews) whose height and width are larger then the physical
   * device screen by design. Such views will _never_ be completely displayed.
   */
  public static Matcher<View> isCompletelyDisplayed() {
    return isDisplayingAtLeast(100);
  }

  /**
   * Returns a matcher which accepts a view so long as a given percentage of that view's area is
   * not obscured by any other view and is thus visible to the user.
   *
   * @param areaPercentage an integer ranging from (0, 100] indicating how much percent of the
   *   surface area of the view must be shown to the user to be accepted.
   */
  public static Matcher<View> isDisplayingAtLeast(final int areaPercentage) {
    checkState(areaPercentage <= 100, "Cannot have over 100 percent: %s", areaPercentage);
    checkState(areaPercentage > 0, "Must have a positive, non-zero value: %s", areaPercentage);
    return new TypeSafeMatcher<View>() {
      @Override
      public void describeTo(Description description) {
        description.appendText(String.format(
            "at least %s percent of the view's area is displayed to the user.", areaPercentage));
      }

      @Override
      public boolean matchesSafely(View view) {
        Rect visibleParts = new Rect();
        boolean visibleAtAll = view.getGlobalVisibleRect(visibleParts);
        if (!visibleAtAll) {
          return false;
        }
        double maxArea = view.getHeight() * view.getWidth();
        double visibleArea = visibleParts.height() * visibleParts.width();
        int displayedPercentage = (int) ((visibleArea / maxArea) * 100);

        return displayedPercentage >= areaPercentage
            && withEffectiveVisibility(Visibility.VISIBLE).matches(view);
      }
    };
  }



  /**
   * Returns a matcher that matches {@link View}s that are enabled.
   */
  public static Matcher<View> isEnabled() {
    return new TypeSafeMatcher<View>() {
      @Override
      public void describeTo(Description description) {
        description.appendText("is enabled");
      }

      @Override
      public boolean matchesSafely(View view) {
        return view.isEnabled();
      }
    };
  }

  /**
   * Returns a matcher that matches {@link View}s that are focusable.
   */
  public static Matcher<View> isFocusable() {
    return new TypeSafeMatcher<View>() {
      @Override
      public void describeTo(Description description) {
        description.appendText("is focusable");
      }

      @Override
      public boolean matchesSafely(View view) {
        return view.isFocusable();
      }
    };
  }

  /**
   * Returns a matcher that matches {@link View}s currently have focus.
   */
  public static Matcher<View> hasFocus() {
    return new TypeSafeMatcher<View>() {
      @Override
      public void describeTo(Description description) {
        description.appendText("has focus on the screen to the user");
      }

      @Override
      public boolean matchesSafely(View view) {
        return view.hasFocus();
      }
    };
  }

  /**
   * Returns an {@link Matcher} that matches {@link View}s based on their siblings.<br>
   * <br>
   * This may be particularly useful when a view cannot be uniquely selected on properties such as
   * text or R.id. For example: a call button is repeated several times in a contacts layout and the
   * only way to differentiate the call button view is by what appears next to it (e.g. the unique
   * name of the contact).
   *
   * @param siblingMatcher a {@link Matcher} for the sibling of the view.
   */
  public static Matcher<View> hasSibling(final Matcher<View> siblingMatcher) {
    checkNotNull(siblingMatcher);
    return new TypeSafeMatcher<View>() {
      @Override
      public void describeTo(Description description) {
        description.appendText("has sibling: ");
        siblingMatcher.describeTo(description);
      }

      @Override
      public boolean matchesSafely(View view) {
        ViewParent parent = view.getParent();
        if (!(parent instanceof ViewGroup)) {
          return false;
        }
        ViewGroup parentGroup = (ViewGroup) parent;
        for (int i = 0; i < parentGroup.getChildCount(); i++) {
          if (siblingMatcher.matches(parentGroup.getChildAt(i))) {
            return true;
          }
        }
        return false;
      }
    };
  }

  /**
   * Returns an {@link Matcher} that matches {@link View}s based on content description property
   * value. Sugar for withContentDescription(is("string")).
   *
   * @param text the text to match on.
   */
  public static Matcher<View> withContentDescription(String text) {
    return withContentDescription(is(text));
  }

  /**
   * Returns an {@link Matcher} that matches {@link View}s based on content description property
   * value.
   *
   * @param charSequenceMatcher a {@link CharSequence} {@link Matcher} for the content description
   */
  public static Matcher<View> withContentDescription(
      final Matcher<? extends CharSequence> charSequenceMatcher) {
    checkNotNull(charSequenceMatcher);
    return new TypeSafeMatcher<View>() {
      @Override
      public void describeTo(Description description) {
        description.appendText("with content description: ");
        charSequenceMatcher.describeTo(description);
      }

      @Override
      public boolean matchesSafely(View view) {
        return charSequenceMatcher.matches(view.getContentDescription());
      }
    };
  }

  /**
   * Sugar for withId(is(int)).
   *
   * @param id the resource id.
   */
  public static Matcher<View> withId(int id) {
    return withId(is(id));
  }

  /**
   * Returns a matcher that matches {@link View}s based on resource ids. Note: Android resource ids
   * are not guaranteed to be unique. You may have to pair this matcher with another one to
   * guarantee a unique view selection.
   *
   * @param integerMatcher a Matcher for resource ids
   */
  public static Matcher<View> withId(final Matcher<Integer> integerMatcher) {
    checkNotNull(integerMatcher);
    return new TypeSafeMatcher<View>() {
      @Override
      public void describeTo(Description description) {
        description.appendText("with id: ");
        integerMatcher.describeTo(description);
      }

      @Override
      public boolean matchesSafely(View view) {
        return integerMatcher.matches(view.getId());
      }
    };
  }

  /**
   * Returns a matcher that matches {@link View} based on tag keys.
   *
   * @param key to match
   */
  public static Matcher<View> withTagKey(final int key) {
    return withTagKey(key, Matchers.<Object>notNullValue());
  }

  /**
   * Returns a matcher that matches {@link View}s based on tag keys.
   *
   * @param key to match
   * @param objectMatcher Object to match
   */
  public static Matcher<View> withTagKey(final int key, final Matcher<Object> objectMatcher) {
    checkNotNull(objectMatcher);
    return new TypeSafeMatcher<View>() {
      @Override
      public void describeTo(Description description) {
        description.appendText("with key: " + key);
        objectMatcher.describeTo(description);
      }

      @Override
      public boolean matchesSafely(View view) {
        return objectMatcher.matches(view.getTag(key));
      }
    };
  }

  /**
   * Returns a matcher that matches {@link View}s based on tag property values.
   *
   * @param tagValueMatcher a Matcher for the view's tag property value
   */
  public static Matcher<View> withTagValue(final Matcher<Object> tagValueMatcher) {
    checkNotNull(tagValueMatcher);
    return new TypeSafeMatcher<View>() {
      @Override
      public void describeTo(Description description) {
        description.appendText("with tag value: ");
        tagValueMatcher.describeTo(description);
      }

      @Override
      public boolean matchesSafely(View view) {
        return tagValueMatcher.matches(view.getTag());
      }
    };
  }

  /**
   * Returns a matcher that matches {@link TextView} based on it's text property value. Note: View's
   * Sugar for withText(is("string")).
   */
  public static Matcher<View> withText(String text) {
    return withText(is(text));
  }

  /**
   * Returns a matcher that matches {@link TextView}s based on text property value. Note: View's
   * text property is never null. If you setText(null) it will still be "". Do not use null matcher.
   *
   * @param stringMatcher {@link Matcher} of {@link String} with text to match
   */
  public static Matcher<View> withText(final Matcher<String> stringMatcher) {
    checkNotNull(stringMatcher);
    return new BoundedMatcher<View, TextView>(TextView.class) {
      @Override
      public void describeTo(Description description) {
        description.appendText("with text: ");
        stringMatcher.describeTo(description);
      }

      @Override
      public boolean matchesSafely(TextView textView) {
        return stringMatcher.matches(textView.getText().toString());
      }
    };
  }

  /**
   * Returns a matcher that matches a descendant of {@link TextView} that is displaying the string
   * associated with the given resource id.
   *
   * @param resourceId the string resource the text view is expected to hold.
   */
  public static Matcher<View> withText(final int resourceId) {

    return new BoundedMatcher<View, TextView>(TextView.class) {
      private String resourceName = null;
      private String expectedText = null;

      @Override
      public void describeTo(Description description) {
        description.appendText("with string from resource id: ");
        description.appendValue(resourceId);
        if (null != resourceName) {
          description.appendText("[");
          description.appendText(resourceName);
          description.appendText("]");
        }
        if (null != expectedText) {
          description.appendText(" value: ");
          description.appendText(expectedText);
        }
      }

      @Override
      public boolean matchesSafely(TextView textView) {
        if (null == expectedText) {
          try {
            expectedText = textView.getResources().getString(resourceId);
            resourceName = textView.getResources().getResourceEntryName(resourceId);
          } catch (Resources.NotFoundException ignored) {
            /* view could be from a context unaware of the resource id. */
          }
        }
        if (null != expectedText) {
          return expectedText.equals(textView.getText());
        } else {
          return false;
        }
      }
    };
  }

  /**
   * Returns a matcher that accepts if and only if the view is a CompoundButton (or subtype of) and
   * is in checked state.
   */
  public static Matcher<View> isChecked() {
    return withCheckBoxState(is(true));
  }

  /**
   * Returns a matcher that accepts if and only if the view is a CompoundButton (or subtype of) and
   * is not in checked state.
   */
  public static Matcher<View> isNotChecked() {
    return withCheckBoxState(is(false));
  }

  private static <E extends View & Checkable> Matcher<View> withCheckBoxState(
      final Matcher<Boolean> checkStateMatcher) {

    return new BoundedMatcher<View, E>(View.class, Checkable.class) {
      @Override
      public void describeTo(Description description) {
        description.appendText("with checkbox state: ");
        checkStateMatcher.describeTo(description);
      }

      @Override
      public boolean matchesSafely(E checkable) {
        return checkStateMatcher.matches(checkable.isChecked());
      }
    };
  }

  /**
   * Returns an {@link Matcher} that matches {@link View}s with any content description.
   */
  public static Matcher<View> hasContentDescription() {
    return new TypeSafeMatcher<View>() {
      @Override
      public void describeTo(Description description) {
        description.appendText("has content description");
      }

      @Override
      public boolean matchesSafely(View view) {
        return view.getContentDescription() != null;
      }
    };
  }

  /**
   * Returns a matcher that matches {@link View}s based on the presence of a descendant in its view
   * hierarchy.
   *
   * @param descendantMatcher the type of the descendant to match on
   */
  public static Matcher<View> hasDescendant(final Matcher<View> descendantMatcher) {
    checkNotNull(descendantMatcher);
    return new TypeSafeMatcher<View>() {
      @Override
      public void describeTo(Description description) {
        description.appendText("has descendant: ");
        descendantMatcher.describeTo(description);
      }

      @Override
      public boolean matchesSafely(final View view) {
        final Predicate<View> matcherPredicate = new Predicate<View>() {
          @Override
          public boolean apply(View input) {
            return input != view && descendantMatcher.matches(input);
          }
        };

        Iterator<View> matchedViewIterator =
            Iterables.filter(breadthFirstViewTraversal(view), matcherPredicate).iterator();

        return matchedViewIterator.hasNext();
      }
    };
  }

  /**
   * Returns a matcher that matches {@link View}s that are clickable.
   */
  public static Matcher<View> isClickable() {
    return new TypeSafeMatcher<View>() {
      @Override
      public void describeTo(Description description) {
        description.appendText("is clickable");
      }

      @Override
      public boolean matchesSafely(View view) {
        return view.isClickable();
      }
    };
  }

  /**
   * Returns a matcher that matches {@link View}s based on the given ancestor type.
   *
   * @param ancestorMatcher the type of the ancestor to match on
   */
  public static Matcher<View> isDescendantOfA(final Matcher<View> ancestorMatcher) {
    checkNotNull(ancestorMatcher);
    return new TypeSafeMatcher<View>() {
      @Override
      public void describeTo(Description description) {
        description.appendText("is descendant of a: ");
        ancestorMatcher.describeTo(description);
      }

      @Override
      public boolean matchesSafely(View view) {
        return checkAncestors(view.getParent(), ancestorMatcher);
      }

      private boolean checkAncestors(
        ViewParent viewParent, Matcher<View> ancestorMatcher) {
        if (!(viewParent instanceof View)) {
          return false;
        }
        if (ancestorMatcher.matches(viewParent)) {
          return true;
        }
        return checkAncestors(viewParent.getParent(), ancestorMatcher);
      }
    };
  }

  /**
   * Returns a matcher that matches {@link View}s that have "effective" visibility set to the given
   * value. Effective visibility takes into account not only the view's visibility value, but also
   * that of its ancestors. In case of View.VISIBLE, this means that the view and all of its
   * ancestors have visibility=VISIBLE. In case of GONE and INVISIBLE, it's the opposite - any GONE
   * or INVISIBLE parent will make all of its children have their effective visibility.
   *
   * <p>
   * <p>
   * Note: Contrary to what the name may imply, view visibility does not directly translate into
   * whether the view is displayed on screen (use isDisplayed() for that). For example, the view and
   * all of its ancestors can have visibility=VISIBLE, but the view may need to be scrolled to in
   * order to be actually visible to the user. Unless you're specifically targeting the visibility
   * value with your test, use isDisplayed.
   */
  public static Matcher<View> withEffectiveVisibility(final Visibility visibility) {
    return new TypeSafeMatcher<View>() {
      @Override
      public void describeTo(Description description) {
        description.appendText(
            String.format("view has effective visibility=%s", visibility));
      }

      @Override
      public boolean matchesSafely(View view) {
        if (visibility.getValue() == View.VISIBLE) {
          if (view.getVisibility() != visibility.getValue()) {
            return false;
          }
          while (view.getParent() != null && view.getParent() instanceof View) {
            view = (View) view.getParent();
            if (view.getVisibility() != visibility.getValue()) {
              return false;
            }
          }
          return true;
        } else {
          if (view.getVisibility() == visibility.getValue()) {
            return true;
          }
          while (view.getParent() != null && view.getParent() instanceof View) {
            view = (View) view.getParent();
            if (view.getVisibility() == visibility.getValue()) {
              return true;
            }
          }
          return false;
        }
      }
    };
  }

  /**
   * Enumerates the possible list of values for View.getVisibility().
   */
  public enum Visibility {
    VISIBLE(View.VISIBLE), INVISIBLE(View.INVISIBLE), GONE(View.GONE);

    private final int value;

    private Visibility(int value) {
      this.value = value;
    }

    public int getValue() {
      return value;
    }
  }

   /**
   * A matcher that accepts a view if and only if the view's parent is accepted by the provided
   * matcher.
   *
   * @param parentMatcher the matcher to apply on getParent.
   */
  public static Matcher<View> withParent(final Matcher<View> parentMatcher) {
    checkNotNull(parentMatcher);
    return new TypeSafeMatcher<View>() {
      @Override
      public void describeTo(Description description) {
        description.appendText("has parent matching: ");
        parentMatcher.describeTo(description);
      }

      @Override
      public boolean matchesSafely(View view) {
        return parentMatcher.matches(view.getParent());
      }
    };
  }

   /**
   * A matcher that returns true if and only if the view's child is accepted by the provided
   * matcher.
   *
   * @param childMatcher the matcher to apply on the child views.
   */
  public static Matcher<View> withChild(final Matcher<View> childMatcher) {
    checkNotNull(childMatcher);
    return new TypeSafeMatcher<View>() {
      @Override
      public void describeTo(Description description) {
        description.appendText("has child: ");
        childMatcher.describeTo(description);
      }

      @Override
      public boolean matchesSafely(View view) {
        if (!(view instanceof ViewGroup)) {
          return false;
        }

        ViewGroup group = (ViewGroup) view;
        for (int i = 0; i < group.getChildCount(); i++) {
          if (childMatcher.matches(group.getChildAt(i))) {
            return true;
          }
        }

        return false;
      }
    };
  }


  /**
   * Returns a matcher that matches root {@link View}.
   */
  public static Matcher<View> isRoot() {
    return new TypeSafeMatcher<View>() {
      @Override
      public void describeTo(Description description) {
        description.appendText("is a root view.");
      }

      @Override
      public boolean matchesSafely(View view) {
        return view.getRootView().equals(view);
      }
    };
  }

  /**
   * Returns a matcher that matches views that support input methods.
   */
  public static Matcher<View> supportsInputMethods() {
    return new TypeSafeMatcher<View>() {
      @Override
      public void describeTo(Description description) {
        description.appendText("supports input methods");
      }

      @Override
      public boolean matchesSafely(View view) {
        // At first glance, it would make sense to use view.onCheckIsTextEditor, but the android
        // javadoc is wishy-washy about whether authors are required to implement this method when
        // implementing onCreateInputConnection.
        return view.onCreateInputConnection(new EditorInfo()) != null;
      }
    };
  }

  /**
   * Returns a matcher that matches views that support input methods (e.g. EditText) and have the
   * specified IME action set in its {@link EditorInfo}.
   *
   * @param imeAction the IME action to match
   */
  public static Matcher<View> hasImeAction(int imeAction) {
    return hasImeAction(is(imeAction));
  }

  /**
   * Returns a matcher that matches views that support input methods (e.g. EditText) and have the
   * specified IME action set in its {@link EditorInfo}.
   *
   * @param imeActionMatcher a matcher for the IME action
   */
  public static Matcher<View> hasImeAction(final Matcher<Integer> imeActionMatcher) {
    return new TypeSafeMatcher<View>() {
      @Override
      public void describeTo(Description description) {
        description.appendText("has ime action: ");
        imeActionMatcher.describeTo(description);
      }

      @Override
      public boolean matchesSafely(View view) {
        EditorInfo editorInfo = new EditorInfo();
        InputConnection inputConnection = view.onCreateInputConnection(editorInfo);
        if (inputConnection == null) {
          return false;
        }
        int actionId = editorInfo.actionId != 0 ? editorInfo.actionId
            : editorInfo.imeOptions & EditorInfo.IME_MASK_ACTION;
        return imeActionMatcher.matches(actionId);
      }
    };
  }

  /**
   * A replacement for MatcherAssert.assertThat that renders View objects nicely.
   *
   * @param actual the actual value.
   * @param matcher a matcher that accepts or rejects actual.
   */
  public static <T> void assertThat(T actual, Matcher<T> matcher) {
    assertThat("", actual, matcher);
  }

  /**
   * A replacement for MatcherAssert.assertThat that renders View objects nicely.
   *
   * @param message the message to display.
   * @param actual the actual value.
   * @param matcher a matcher that accepts or rejects actual.
   */
  public static <T> void assertThat(String message, T actual, Matcher<T> matcher) {
    if (!matcher.matches(actual)) {
      Description description = new StringDescription();
      description.appendText(message)
          .appendText("\nExpected: ")
          .appendDescriptionOf(matcher)
          .appendText("\n     Got: ");
      if (actual instanceof View) {
        description.appendValue(HumanReadables.describe((View) actual));
      } else {
        description.appendValue(actual);
      }
      description.appendText("\n");
      throw new AssertionFailedError(description.toString());
    }
  }
}