ContributorAppIntegrationTest.java

package com.example.retrofit;

import org.junit.Test;

import java.io.ByteArrayOutputStream;
import java.io.PrintStream;

import static junit.framework.TestCase.assertTrue;

// 一般來說，只要把名稱取為 ContributorAppTest 即可
public class ContributorAppIntegrationTest {

    @Test
    public void When_GetContributor_Should_GetMoreThan1() throws Exception {
        // Arrange
        ByteArrayOutputStream stream = new ByteArrayOutputStream();
        PrintStream printStream = new PrintStream(stream);
        System.setOut(printStream);

        SimpleRefactorService.ContributorApp app =
                new SimpleRefactorService.ContributorApp(
                        new SimpleRefactorService.ContributorManagerImpl(),
                        new SimpleRefactorService.ContributorPresenterImpl());

        // Action
        app.execute();

        // Assert
        assertTrue(stream.toString().split(System.lineSeparator()).length > 1);
    }

    @Test
    public void When_GetContributor_Should_ContainJakeWharton() throws Exception {
        // Arrange
        ByteArrayOutputStream stream = new ByteArrayOutputStream();
        PrintStream printStream = new PrintStream(stream);
        System.setOut(printStream);

        SimpleRefactorService.ContributorApp app =
                new SimpleRefactorService.ContributorApp(
                        new SimpleRefactorService.ContributorManagerImpl(),
                        new SimpleRefactorService.ContributorPresenterImpl());

        // Action
        app.execute();

        // Assert
        assertTrue(stream.toString().contains("JakeWharton"));
    }
}

ContributorAppUnitTest.java

package com.example.retrofit;

import org.junit.Test;

import java.io.IOException;

import static junit.framework.TestCase.assertEquals;

// 一般來說，只要把名稱取為 ContributorAppTest 即可
public class ContributorAppUnitTest {

    @Test
    public void When_Get2Contributors_Then_Present2Contributors() throws IOException{
        // Arrange
        MockContributorManager manager = new MockContributorManager();
        MockContributorPresenter presenter = new MockContributorPresenter();
        SimpleRefactorService.ContributorApp testee =
                new SimpleRefactorService.ContributorApp(manager, presenter);

        // Action
        testee.execute();

        // Assert
        assertEquals(2, presenter.getPresentCount());
    }
}

MockContributorManager.java

package com.example.retrofit;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

public class MockContributorManager implements SimpleRefactorService.ContributorManager {

    @Override
    public List<SimpleRefactorService.Contributor> getContributors() throws IOException {
        List<SimpleRefactorService.Contributor> contributors = new ArrayList<>();
        contributors.add(new SimpleRefactorService.Contributor("JakeWharton", 1000));
        contributors.add(new SimpleRefactorService.Contributor("ElvisLin", 1000));
        return contributors;
    }
}

MockContributorPresenter.java

package com.example.retrofit;

import java.util.List;

public class MockContributorPresenter implements SimpleRefactorService.ContributorPresenter {

    private int presentCount = 0;

    @Override
    public void presentContributors(List<SimpleRefactorService.Contributor> contributors) {
        for (SimpleRefactorService.Contributor contributor : contributors) {
            presentCount++;
        }
    }

    public int getPresentCount() {
        return presentCount;
    }
}

SimpleRefactorService.java

/*
 * Copyright (C) 2012 Square, Inc.
 *
 * 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.retrofit;

import retrofit2.Call;
import retrofit2.Retrofit;
import retrofit2.converter.gson.GsonConverterFactory;
import retrofit2.http.GET;
import retrofit2.http.Path;

import java.io.IOException;
import java.util.List;

public final class SimpleRefactorService {
    public static final String API_URL = "https://api.github.com";

    public static class Contributor {
        public final String login;
        public final int contributions;

        public Contributor(String login, int contributions) {
            this.login = login;
            this.contributions = contributions;
        }
    }

    public interface GitHub {
        @GET("/repos/{owner}/{repo}/contributors")
        Call<List<Contributor>> contributors(
                @Path("owner") String owner,
                @Path("repo") String repo);
    }

    public interface ContributorManager {
        List<Contributor> getContributors() throws IOException;
    }

    public static class ContributorManagerImpl implements ContributorManager {

        public List<Contributor> getContributors() throws IOException {
            // Create a very simple REST adapter which points the GitHub API.
            Retrofit retrofit = new Retrofit.Builder()
                    .baseUrl(API_URL)
                    .addConverterFactory(GsonConverterFactory.create())
                    .build();

            // Create an instance of our GitHub API interface.
            GitHub github = retrofit.create(GitHub.class);

            // Create a call instance for looking up Retrofit contributors.
            Call<List<Contributor>> call = github.contributors("square", "retrofit");

            // Fetch and print a list of the contributors to the library.
            List<Contributor> contributors = call.execute().body();
            return contributors;
        }
    }

    public interface ContributorPresenter {
        void presentContributors(List<Contributor> contributors);
    }

    public static class ContributorPresenterImpl implements ContributorPresenter {
        public void presentContributors(List<Contributor> contributors) {
            for (Contributor contributor : contributors) {
                System.out.println(contributor.login + " (" + contributor.contributions + ")");
            }
        }
    }

    public static class ContributorApp {
        private ContributorManager manager;
        private ContributorPresenter presenter;

        public ContributorApp(ContributorManager manager, ContributorPresenter presenter) {
            this.manager = manager;
            this.presenter = presenter;
        }

        public void execute() throws IOException {
            List<Contributor> contributors = manager.getContributors();
            presenter.presentContributors(contributors);
        }
    }

    public static void main(String... args) throws IOException {

        ContributorApp app = new ContributorApp(new ContributorManagerImpl(), new ContributorPresenterImpl());
        app.execute();

    }
}