package hello.hello_spock;

import static org.junit.Assert.assertEquals;

import static org.mockito.ArgumentMatchers.any;

import static org.mockito.ArgumentMatchers.anyString;

import static org.mockito.Mockito.mock;

import static org.mockito.Mockito.when;

import org.junit.Test;

import org.junit.runner.RunWith;

import org.mockito.junit.MockitoJUnitRunner;

import org.springframework.http.HttpMethod;

import org.springframework.web.client.RequestCallback;

import org.springframework.web.client.ResponseExtractor;

import org.springframework.web.client.RestTemplate;

@RunWith(MockitoJUnitRunner.class)

public class RestTemplateTest {

  @SuppressWarnings("unchecked")

  @Test

  public void testRestTemplate() {

    RestTemplate restTemplate = mock(RestTemplate.class);

    when(restTemplate.execute(anyString(),

        any(HttpMethod.class), any(RequestCallback.class), any(ResponseExtractor.class)))

            .thenReturn("123");

    String aString=restTemplate.execute("http://www.baidu.com", HttpMethod.GET, x->System.out.println("a"), x-> "" );

    assertEquals(aString, "123");

  }

}

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">

    <modelVersion>4.0.0</modelVersion>

    <groupId>hello</groupId>

    <artifactId>hello_spock</artifactId>

    <version>0.0.1-SNAPSHOT</version>

    <packaging>jar</packaging>

    <name>hello_spock</name>

    <url>http://maven.apache.org</url>

    <properties>

        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>

    </properties>

    <build>

        <plugins>

            <plugin>

                <artifactId>maven-compiler-plugin</artifactId>

                <version>3.3</version>

                <configuration>

                    <source>1.8</source>

                    <target>1.8</target>

                </configuration>

            </plugin>

        </plugins>

    </build>

    <dependencies>

        <dependency>

            <groupId>junit</groupId>

            <artifactId>junit</artifactId>

            <version>4.11</version>

            <scope>test</scope>

        </dependency>

        <dependency>

            <groupId>org.mockito</groupId>

            <artifactId>mockito-core</artifactId>

            <version>2.13.0</version>

        </dependency>

        <dependency>

            <groupId>org.springframework</groupId>

            <artifactId>spring-web</artifactId>

            <version>5.0.2.RELEASE</version>

        </dependency>

    </dependencies>

</project>