Demo1

Activity代码：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context="com.example.yimo.myapplication.MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!"
        android:id="@+id/textView" />

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="textPersonName"
        android:text="Enter your  name"
        android:ems="10"
        android:hint="Enter your name"
        android:id="@+id/editText" />

    <Button
        android:text="sayHello"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/editText"
        android:layout_toEndOf="@+id/textView"
       android:layout_gravity="center"
        android:onClick="sayHello"
        android:id="@+id/button" />
</LinearLayout>



Java代码：

public class MainActivity extends AppCompatActivity {


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

            }

    public void sayHello(View view){
        TextView textView=(TextView) findViewById(R.id.textView);
        EditText editText=(EditText)findViewById(R.id.editText);
        textView.setText("Hello,"+editText.getText().toString()+"!");
    }


}


Test代码：

package com.example.yimo.myapplication;

import android.support.test.espresso.ViewAssertion;
import android.support.test.rule.ActivityTestRule;
import android.view.View;

import org.hamcrest.Matcher;
import org.junit.Rule;
import org.junit.Test;

import static android.support.test.espresso.Espresso.onView;
import static android.support.test.espresso.action.ViewActions.click;
import static android.support.test.espresso.action.ViewActions.typeText;
import static android.support.test.espresso.assertion.ViewAssertions.matches;
import static android.support.test.espresso.matcher.ViewMatchers.withId;
import static android.support.test.espresso.matcher.ViewMatchers.withText;
import static org.junit.Assert.*;

/**
 * Created by yimo on 2017/3/18.
 */
public class MainActivityTest {
    private static  final String STRING_TO_BE_TYPED="Peter";
    @Rule
    public ActivityTestRule<MainActivity> mActivityRule=new ActivityTestRule<>(MainActivity.class);

    @Test
    public void sayHello(){
        onView(withId(R.id.editText)).perform(typeText(STRING_TO_BE_TYPED));

        onView(withId(R.id.button)).perform(click());
        String expectedText="Hello,"+STRING_TO_BE_TYPED+"!";
        onView(withId(R.id.textView)).check(matches(withText(expectedText)));
    }




}