[JAVA] MOCK constructors of other classes with Spring MVC + PowerMock + Junit

How to use PowerMock

Environmental information

• Junit-4.12
• PowerMock1.6.2

domain/pom.xml(Excerpt)

		<!-- https://mvnrepository.com/artifact/com.jcraft/jsch -->
		<dependency>
			<groupId>com.jcraft</groupId>
			<artifactId>jsch</artifactId>
			<version>0.1.54</version>
		</dependency>
		<!-- https://mvnrepository.com/artifact/org.powermock/powermock -->
		<dependency>
			<groupId>org.powermock</groupId>
			<artifactId>powermock-module-junit4-legacy</artifactId>
			<version>${powermock.version}</version>
			<scope>test</scope>
		</dependency>
		<dependency>
			<groupId>org.powermock</groupId>
			<artifactId>powermock-module-junit4</artifactId>
			<version>${powermock.version}</version>
			<scope>test</scope>
		</dependency>
		<dependency>
			<groupId>org.powermock</groupId>
			<artifactId>powermock-api-mockito</artifactId>
			<version>${powermock.version}</version>
			<scope>test</scope>
		</dependency>
		<dependency>
			<groupId>org.powermock</groupId>
			<artifactId>powermock-module-junit4-rule</artifactId>
			<version>${powermock.version}</version>
			<scope>test</scope>
		</dependency>
		<dependency>
			<groupId>org.powermock</groupId>
			<artifactId>powermock-classloading-xstream</artifactId>
			<version>${powermock.version}</version>
			<scope>test</scope>
		</dependency>
	</dependencies>

Test class

package training.domain.service;

import static org.hamcrest.CoreMatchers.*;
import static org.junit.Assert.*;
import static org.mockito.Matchers.any;
import static org.mockito.Mockito.*;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.MockitoAnnotations;
import org.powermock.api.mockito.PowerMockito;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;
import org.powermock.modules.junit4.PowerMockRunnerDelegate;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

@RunWith(PowerMockRunner.class)
@PrepareForTest(CallJsch.class)
@PowerMockRunnerDelegate(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = {"classpath:test-context.xml"})
public class CallJschTest {

	@Mock
	private JschTraining mock;

	@InjectMocks
	public CallJsch target = spy(new CallJsch());

	@Test
	public void test1() throws Exception {
		{
			MockitoAnnotations.initMocks(this);

			PowerMockito.whenNew(JschTraining.class).withAnyArguments().thenReturn(mock);
			PowerMockito.when(mock.exec(any())).thenReturn("SUCCESS");
		}

		target = new CallJsch();
		String str = target.call("root", "127.0.0.0", 22, "Administrator", 10);
		assertThat(str ,is("SUCCESS"));

	}

}

Test target

package training.domain.service;

import java.io.IOException;

import com.jcraft.jsch.JSchException;
import com.jcraft.jsch.SftpException;

public class CallJsch {

	public String call(String user, String host, int port, String password, int timeout)
			throws JSchException, IOException, SftpException, Exception {
		JschTraining target = new JschTraining(user, host, port, password, timeout);
		return target.exec("ECHO TEST");
	}

}

Class called by the test target

package training.domain.service;

import java.io.BufferedInputStream;
import java.io.ByteArrayOutputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.nio.charset.StandardCharsets;

import com.jcraft.jsch.ChannelExec;
import com.jcraft.jsch.JSch;
import com.jcraft.jsch.JSchException;
import com.jcraft.jsch.Session;
import com.jcraft.jsch.SftpException;

public class JschTraining {

	JSch jsch;
	Session session;
	ChannelExec channel;

	public JschTraining(String user, String host, int port, String password, int timeout) throws JSchException {
		jsch = new JSch();
		session = jsch.getSession(user, host, port);
		// known_Skip hosts check
		session.setConfig("StrictHostKeyChecking", "no");
		session.setPassword(password);
		session.setTimeout(timeout);
		session.connect();
		channel = (ChannelExec) session.openChannel("exec");
	}

	public String exec(String command) throws JSchException, SftpException, FileNotFoundException, IOException {
		BufferedInputStream bin = null;
		ByteArrayOutputStream bout = null;
		try {
			channel.setCommand(command);
			channel.connect();

			//Command execution
			bin = new BufferedInputStream(channel.getInputStream());
			bout = new ByteArrayOutputStream();
			byte[] buf = new byte[1024];
			int length;
			while (true) {
				length = bin.read(buf);
				if (length == -1) {
					break;
				}
				bout.write(buf, 0, length);
			}
			//Standard output
			System.out.format("Execution result=%1$s", new String(bout.toByteArray(), StandardCharsets.UTF_8));
		} finally {
			if (bin != null) {
				try {
					bin.close();
				} catch (IOException e) {
				}
			}
			if (channel != null) {
				try {
					channel.disconnect();
				} catch (Exception e) {
				}
			}
			if (session != null) {
				try {
					session.disconnect();
				} catch (Exception e) {
				}
			}
		}
		return new String(bout.toByteArray(), StandardCharsets.UTF_8);
	}
}

point

@PrepareForTest (CallJsch.class) ← This is the class to be tested

@Mock private JschTraining mock; ← Here are other classes called by the test subject