I have to start this post from the fact that I love Spock library and for some time I write tests only with use of it. I recently had the task to do API documentation and decided to do it with the help of the REST Assured library. There are a lot of guides and documentation on how to run REST Assured tests in conjunction with JUnit, but few (even less good) regarding the connection with Spock. Unfortunately for some reason I encountered a lot of problems when solving these task. In the end I managed to do it and that’s why I writing this text. Gathering all this I would like to describe how to use Spock and REST Assured to generate documentation of REST API and attach it to the project.

This is root project build.gradle file:

plugins {
	id 'org.springframework.boot' version '2.2.2.RELEASE'
	id 'io.spring.dependency-management' version '1.0.8.RELEASE'
	id 'org.asciidoctor.convert' version '1.6.1'
	id 'groovy'

group = 'pl.codeaddict'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '11'

repositories {

ext {
	snippetsDir = "$buildDir/generated-snippets"
	spockVersion = '1.3-groovy-2.5'
	springRestDocsVersion = '2.0.4.RELEASE'
	lombokVersion = '1.18.10'

dependencies {
	implementation 'org.springframework.boot:spring-boot-starter-web'

	compileOnly "org.projectlombok:lombok:$lombokVersion"

	testImplementation "org.spockframework:spock-core:$spockVersion"
	testImplementation "org.spockframework:spock-spring:$spockVersion"
	testImplementation('org.springframework.boot:spring-boot-starter-test') {
		exclude group: 'org.junit.vintage', module: 'junit-vintage-engine'
	asciidoctor "org.springframework.restdocs:spring-restdocs-asciidoctor:$springRestDocsVersion"
	testImplementation("org.springframework.restdocs:spring-restdocs-restassured:$springRestDocsVersion") {
		exclude group: 'com.sun.xml.bind', module: 'jaxb-osgi'

	annotationProcessor "org.projectlombok:lombok:$lombokVersion"

test {
	outputs.dir snippetsDir

task copyAsciidocTemplate(type: Copy) {
	dependsOn test
	from "src/docs/asciidoc"
	into snippetsDir

asciidoctor {
	dependsOn copyAsciidocTemplate
	sourceDir snippetsDir
	doLast {
		copy {
			from "$buildDir/asciidoc/html5"
			into "$buildDir/resources/main/public/docs"
			include "**/*.html"


As you can see in the file above there are a few things to do in order to add Spock and Rest assured. In addition to the obvious, i.e. adding libraries, I configured the path where parts of the API documentation will be generated:

snippetsDir = "$buildDir/generated-snippets"

I also created a task (copyAsciidocTemplate) that will copy the template document from the src/docs/asciidoc directory to the same directory where the fragments of API documentation will be generated. Some tutorials show that the generated parts are thrown into the src directory. but for me it is a bad approach..

The configuration of the ascidoc -> html converter plugin (org.asciidoctor.convert) should be placed in the asciidoctor task. I also added there a fragment that copies the generated files to the resources directory, which causes them to be added to the application jar. The last line connects the task ascidoctor with the bootRun task, so it’s build documentation when bootRun task is run.

I have also added a groovy plugin. Remember that after adding it, the Java plugin will also be added automatically so you don’t have to add it anymore.

An important part of the application is the documentation template /src/docs/asciidocs/api.adoc:

= Blog demo API

== Login


== Add Post


== Modify Post


== Get Post


It is a file that collects all generated fragments into a whole. For example, operation::get_post defines the parts of the documentation for the operation get_post (the name defined in the BlogApiDocumentationSpec.groovy tests, line 137). Please note that curl-request,path-parameters,request-headers,response-body,response-fields fragments must be generated by our test code (but more on this in a moment).

I will not paste the entire test class, only the method testing the get_post operation and generating the fragments used in the template described above:

    void "get post details"() {
        final request =
                        .header("Authorization", "Bearer TOKEN")
                                                        .description("Blog post unique identification number")),
                                                        .description("Blog post identification number"),
                                                        .description("Blog post text"),
                                                        "Token for user authentication"))

        final response = request.get('/api/post/{id}', [id: "123-4234"])

        response.statusCode() == HttpStatus.OK.value()

In given section we define what our request should look like and what response we expect. We set the Accept and Content-type request headers to the value MediaType.APPLICATION_JSON_VALUE and custom Authorization header to value Bearer TOKEN. Then in the filter method we describe how the request and response should look like and what specific parameters mean (description methods). At this point, we also define fragments of documentation that we list in the template (e.g. request-headers). All elements defined in filter will be checked during tests. In when section we running our request with the id path parameter equal to “123-4234”. In then section we perform a simple check whether the response code is 200. I invite you to my Github account for the whole class.

I added a simple controller in the application:

package pl.codeaddict.spockapidocs;

import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

public class BlogApiController {

    public ResponseEntity<Void> login(LoginRequest loginRequest) {
        return ResponseEntity.ok().header("Set-Auth-Token", "TOKEN").build();

    public ResponseEntity<AddPostResponse> addPost(AddPostRequest addPostRequest) {
        return ResponseEntity.ok().body(new AddPostResponse("111-333"));

    public ResponseEntity<Void> modifyPost(@PathVariable String id, ModifyPostRequest modifyPostRequest) {
        return ResponseEntity.ok().build();

    public ResponseEntity<GetPostDetailsResponse> getPostDetails(@PathVariable String id) {
        return ResponseEntity.ok().body(new GetPostDetailsResponse("111-333","Blog post text"));


I will not describe it in more detail, but if you want to expand your knowledge, I encourage you to read the Spring tutorials and documentation about RESTfull web services.

You can now start the applications by running ./gradlew bootRun command in project directory. Open http://localhost:8080/docs/api.html address in your browser and enjoy beautiful documentation.

This is it! You can find all the source code in my repository GitHub account. Have fun and thanks for reading!