spockframework/spock

├── pom.xml     //1.here inherit from spring-boot-starter-parent
├── README.md
└── spocky
    ├── pom.xml //2.spock depency 
    ├── spocky.iml
    └── src
        ├── main
        │   ├── java
        │   └── resources
        └── test
            ├── groovy
            │   └── com
            │       └── abc
            │           └── DemoSpec.groovy
            └── java
                └── DemoTest.java

//1.pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.4.4</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <groupId>com.abc</groupId>
    <artifactId>demo-parent</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>xxxx</name>
    <description>xxx</description>
    <packaging>pom</packaging>

    <modules>
        <module>spocky</module>
    </modules>
</project>


//2.spock depency pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<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">
    <parent>
        <artifactId>internal-control-parent</artifactId>
        <groupId>com.abc</groupId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>spocky</artifactId>

    <dependencies>
        <dependency>
            <groupId>org.spockframework</groupId>
            <artifactId>spock-core</artifactId>
            <version>2.0-groovy-3.0</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.spockframework</groupId>
            <artifactId>spock-spring</artifactId>
            <version>2.0-groovy-3.0</version>
            <scope>test</scope>
        </dependency>
   <!--
        with this or not, still the same ERROR:Groovyc....
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <version>2.5.0</version>
            <scope>test</scope>
        </dependency>

    --> 

    </dependencies>


    <build>
        <plugins>
            <plugin>
                <groupId>org.codehaus.gmavenplus</groupId>
                <artifactId>gmavenplus-plugin</artifactId>
                <version>1.12.1</version>
                <executions>
                    <execution>
                        <goals>
                            <goal>compile</goal>
                            <goal>compileTests</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
            <plugin>
                <artifactId>maven-surefire-plugin</artifactId>
                <version>2.22.2</version>
                <configuration>
                    <useFile>false</useFile>
                    <includes>
                        <include>**/*Spec.java</include>
                    </includes>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>


//3.DemoSpec.groovy

package com.abc;

import spock.lang.Specification

class DemoSpec extends Specification {
    def "an integer can be incremented"() {
        given:
        int i = 1
        when:
        i++
        then:
        i == 2
    }
}