Test Activity with Robolectric

SetValueTest.java

/*
 * Copyright 2018 Herman Cheung
 *
 * 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 hkhc.robolectrictest;


import android.app.Activity;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.widget.TextView;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.robolectric.Robolectric;
import org.robolectric.RobolectricTestRunner;
import org.robolectric.annotation.Config;

import static junit.framework.Assert.assertEquals;

@RunWith(RobolectricTestRunner.class)
@Config(manifest="AndroidManifest.xml", sdk=24)
public class SetValueTest {

    static class Student {
        private String id;

        String getId() {
            return id;
        }

        void setId(String id) {
            this.id = id;
        }
    }

    static class MyActivity extends Activity {

        TextView tView;
        Student s;

        @Override
        protected void onCreate(@Nullable Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            tView = (TextView) findViewById(R.id.text);
            someOtherMethod();
        }

        public void setValue() {
            String id = s.getId();
            tView.setText(id);
        }
        public void someOtherMethod(){
            s =new Student();
            s.setId("123");
        }

    }

    @Test
    public void testSetValue() {

        MyActivity myActivity = Robolectric.setupActivity(MyActivity.class);
        myActivity.setValue();;
        TextView tView = myActivity.findViewById(R.id.text);

        assertEquals("123", tView.getText().toString());

    }


}