OrderActivityBasicTest.java

/*
* Copyright (C) 2017 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
*  	http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

package com.example.android.teatime;



import static androidx.test.espresso.Espresso.onView;
import static androidx.test.espresso.action.ViewActions.click;
import static androidx.test.espresso.assertion.ViewAssertions.matches;
import static androidx.test.espresso.matcher.ViewMatchers.withId;
import static androidx.test.espresso.matcher.ViewMatchers.withText;

import androidx.test.ext.junit.runners.AndroidJUnit4;
import androidx.test.rule.ActivityTestRule;

import org.junit.Rule;
import org.junit.Test;
import org.junit.runner.RunWith;

/**
 * This test demos a user clicking the decrement button and verifying that it properly decrease
 * the quantity the total cost.
 */

@RunWith(AndroidJUnit4.class)
public class OrderActivityBasicTest {

    /**
     * The ActivityTestRule is a rule provided by Android used for functional testing of a single
     * activity. The activity that will be tested will be launched before each test that's annotated
     * with @Test and before methods annotated with @before. The activity will be terminated after
     * the test and methods annotated with @After are complete. This rule allows you to directly
     * access the activity during the test.
     */

    @Rule
    public ActivityTestRule<OrderActivity> mActivityTestRule =
            new ActivityTestRule<>(OrderActivity.class);

    @Test
    public void clickDecrementButton_ChangesQuantityAndCost() {

        // Check the initial quantity variable is zero
        onView((withId(R.id.quantity_text_view))).check(matches(withText("0")));

        // Click on decrement button
        onView((withId(R.id.decrement_button)))
                .perform(click());

        // Verify that the decrement button decreases the quantity by 1
        onView(withId(R.id.quantity_text_view)).check(matches(withText("0")));

        // Verify that the increment button also increases the total cost to $5.00
        onView(withId(R.id.cost_text_view)).check(matches(withText("$0.00")));

    }
}