Remove support for JUnit 4

Closes gh-958

Author: wilkinsona

docs/build.gradle

@@ -18,7 +18,6 @@ dependencies {
 	testImplementation(project(":spring-restdocs-webtestclient"))
 	testImplementation("jakarta.servlet:jakarta.servlet-api")
 	testImplementation("jakarta.validation:jakarta.validation-api")
-	testImplementation("junit:junit")
 	testImplementation("org.testng:testng:6.9.10")
 	testImplementation("org.junit.jupiter:junit-jupiter-api")
 }

docs/src/docs/asciidoc/getting-started.adoc

@@ -203,8 +203,7 @@ It then produces documentation snippets for the request and the resulting respon
 ==== Setting up Your Tests
 
 Exactly how you set up your tests depends on the test framework that you use.
-Spring REST Docs provides first-class support for JUnit 5 and JUnit 4.
-JUnit 5 is recommended.
+Spring REST Docs provides first-class support for JUnit 5.
 Other frameworks, such as TestNG, are also supported, although slightly more setup is required.
 
 
@@ -258,72 +257,6 @@ public class JUnit5ExampleTests {
 Next, you must provide a `@BeforeEach` method to configure MockMvc or WebTestClient, or REST Assured.
 The following listings show how to do so:
 
-[source,java,indent=0,role="primary"]
-.MockMvc
-----
-include::{examples-dir}/com/example/mockmvc/ExampleApplicationJUnit5Tests.java[tags=setup]
-----
-<1> The `MockMvc` instance is configured by using a `MockMvcRestDocumentationConfigurer`.
-You can obtain an instance of this class from the static `documentationConfiguration()` method on `org.springframework.restdocs.mockmvc.MockMvcRestDocumentation`.
-
-[source,java,indent=0,role="secondary"]
-.WebTestClient
-----
-include::{examples-dir}/com/example/webtestclient/ExampleApplicationJUnit5Tests.java[tags=setup]
-----
-<1> The `WebTestClient` instance is configured by adding a `WebTestClientRestDocumentationConfigurer` as an `ExchangeFilterFunction`.
-You can obtain an instance of this class from the static `documentationConfiguration()` method on `org.springframework.restdocs.webtestclient.WebTestClientRestDocumentation`.
-
-[source,java,indent=0,role="secondary"]
-.REST Assured
-----
-include::{examples-dir}/com/example/restassured/ExampleApplicationJUnit5Tests.java[tags=setup]
-----
-<1> REST Assured is configured by adding a `RestAssuredRestDocumentationConfigurer` as a `Filter`.
-You can obtain an instance of this class from the static `documentationConfiguration()` method on `RestAssuredRestDocumentation` in the `org.springframework.restdocs.restassured` package.
-
-The configurer applies sensible defaults and also provides an API for customizing the configuration.
-See the <<configuration, configuration section>> for more information.
-
-
-
-[[getting-started-documentation-snippets-setup-junit]]
-===== Setting up Your JUnit 4 Tests
-
-When using JUnit 4, the first step in generating documentation snippets is to declare a `public` `JUnitRestDocumentation` field that is annotated as a JUnit `@Rule`.
-The following example shows how to do so:
-
-[source,java,indent=0]
-----
-@Rule
-public JUnitRestDocumentation restDocumentation = new JUnitRestDocumentation();
-----
-
-By default, the `JUnitRestDocumentation` rule is automatically configured with an output directory based on your project's build tool:
-
-[cols="2,5"]
-|===
-| Build tool | Output directory
-
-| Maven
-| `target/generated-snippets`
-
-| Gradle
-| `build/generated-snippets`
-|===
-
-You can override the default by providing an output directory when you create the `JUnitRestDocumentation` instance.
-The following example shows how to do so:
-
-[source,java,indent=0]
-----
-@Rule
-public JUnitRestDocumentation restDocumentation = new JUnitRestDocumentation("custom");
-----
-
-Next, you must provide an `@Before` method to configure MockMvc or WebTestClient, or REST Assured.
-The following examples show how to do so:
-
 [source,java,indent=0,role="primary"]
 .MockMvc
 ----
@@ -337,7 +270,7 @@ You can obtain an instance of this class from the static `documentationConfigura
 ----
 include::{examples-dir}/com/example/webtestclient/ExampleApplicationTests.java[tags=setup]
 ----
-<1> The `WebTestClient` instance is configured by adding a `WebTestclientRestDocumentationConfigurer` as an `ExchangeFilterFunction`.
+<1> The `WebTestClient` instance is configured by adding a `WebTestClientRestDocumentationConfigurer` as an `ExchangeFilterFunction`.
 You can obtain an instance of this class from the static `documentationConfiguration()` method on `org.springframework.restdocs.webtestclient.WebTestClientRestDocumentation`.
 
 [source,java,indent=0,role="secondary"]
@@ -353,16 +286,15 @@ See the <<configuration, configuration section>> for more information.
 
 
 
+
 [[getting-started-documentation-snippets-setup-manual]]
 ===== Setting up your tests without JUnit
 
-The configuration when JUnit is not being used is largely similar to when it is being used.
-This section describes the key differences.
-The {samples}/testng[TestNG sample] also illustrates the approach.
+The configuration when JUnit is not being used is a little more involved as the test class must perform some lifecycle management.
+The {samples}/testng[TestNG sample] illustrates the approach.
 
-The first difference is that you should use `ManualRestDocumentation` in place of `JUnitRestDocumentation`.
-Also, you do not need the `@Rule` annotation.
-The following example shows how to use `ManualRestDocumentation`:
+First, you need a `ManualRestDocumentation` field.
+The following example shows how to define it:
 
 [source,java,indent=0]
 ----

docs/src/test/java/com/example/mockmvc/CustomDefaultOperationPreprocessors.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2023 the original author or authors.
+ * Copyright 2014-2025 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,10 +16,11 @@
 
 package com.example.mockmvc;
 
-import org.junit.Before;
-import org.junit.Rule;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.extension.ExtendWith;
 
-import org.springframework.restdocs.JUnitRestDocumentation;
+import org.springframework.restdocs.RestDocumentationContextProvider;
+import org.springframework.restdocs.RestDocumentationExtension;
 import org.springframework.test.web.servlet.MockMvc;
 import org.springframework.test.web.servlet.setup.MockMvcBuilders;
 import org.springframework.web.context.WebApplicationContext;
@@ -28,21 +29,19 @@
 import static org.springframework.restdocs.operation.preprocess.Preprocessors.modifyHeaders;
 import static org.springframework.restdocs.operation.preprocess.Preprocessors.prettyPrint;
 
-public class CustomDefaultOperationPreprocessors {
-
-	@Rule
-	public final JUnitRestDocumentation restDocumentation = new JUnitRestDocumentation();
+@ExtendWith(RestDocumentationExtension.class)
+class CustomDefaultOperationPreprocessors {
 
 	private WebApplicationContext context;
 
 	@SuppressWarnings("unused")
 	private MockMvc mockMvc;
 
-	@Before
-	public void setup() {
+	@BeforeEach
+	void setup(RestDocumentationContextProvider restDocumentation) {
 		// tag::custom-default-operation-preprocessors[]
 		this.mockMvc = MockMvcBuilders.webAppContextSetup(this.context)
-			.apply(documentationConfiguration(this.restDocumentation).operationPreprocessors()
+			.apply(documentationConfiguration(restDocumentation).operationPreprocessors()
 				.withRequestDefaults(modifyHeaders().remove("Foo")) // <1>
 				.withResponseDefaults(prettyPrint())) // <2>
 			.build();

docs/src/test/java/com/example/mockmvc/CustomDefaultSnippets.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2023 the original author or authors.
+ * Copyright 2014-2025 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,34 +16,33 @@
 
 package com.example.mockmvc;
 
-import org.junit.Before;
-import org.junit.Rule;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.extension.ExtendWith;
 
 import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.restdocs.JUnitRestDocumentation;
+import org.springframework.restdocs.RestDocumentationContextProvider;
+import org.springframework.restdocs.RestDocumentationExtension;
 import org.springframework.test.web.servlet.MockMvc;
 import org.springframework.test.web.servlet.setup.MockMvcBuilders;
 import org.springframework.web.context.WebApplicationContext;
 
 import static org.springframework.restdocs.cli.CliDocumentation.curlRequest;
 import static org.springframework.restdocs.mockmvc.MockMvcRestDocumentation.documentationConfiguration;
 
-public class CustomDefaultSnippets {
-
-	@Rule
-	public final JUnitRestDocumentation restDocumentation = new JUnitRestDocumentation();
+@ExtendWith(RestDocumentationExtension.class)
+class CustomDefaultSnippets {
 
 	@Autowired
 	private WebApplicationContext context;
 
 	@SuppressWarnings("unused")
 	private MockMvc mockMvc;
 
-	@Before
-	public void setUp() {
+	@BeforeEach
+	void setUp(RestDocumentationContextProvider restDocumentation) {
 		// tag::custom-default-snippets[]
 		this.mockMvc = MockMvcBuilders.webAppContextSetup(this.context)
-			.apply(documentationConfiguration(this.restDocumentation).snippets().withDefaults(curlRequest()))
+			.apply(documentationConfiguration(restDocumentation).snippets().withDefaults(curlRequest()))
 			.build();
 		// end::custom-default-snippets[]
 	}

docs/src/test/java/com/example/mockmvc/CustomEncoding.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2023 the original author or authors.
+ * Copyright 2014-2025 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,33 +16,32 @@
 
 package com.example.mockmvc;
 
-import org.junit.Before;
-import org.junit.Rule;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.extension.ExtendWith;
 
 import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.restdocs.JUnitRestDocumentation;
+import org.springframework.restdocs.RestDocumentationContextProvider;
+import org.springframework.restdocs.RestDocumentationExtension;
 import org.springframework.test.web.servlet.MockMvc;
 import org.springframework.test.web.servlet.setup.MockMvcBuilders;
 import org.springframework.web.context.WebApplicationContext;
 
 import static org.springframework.restdocs.mockmvc.MockMvcRestDocumentation.documentationConfiguration;
 
-public class CustomEncoding {
-
-	@Rule
-	public final JUnitRestDocumentation restDocumentation = new JUnitRestDocumentation();
+@ExtendWith(RestDocumentationExtension.class)
+class CustomEncoding {
 
 	@Autowired
 	private WebApplicationContext context;
 
 	@SuppressWarnings("unused")
 	private MockMvc mockMvc;
 
-	@Before
-	public void setUp() {
+	@BeforeEach
+	void setUp(RestDocumentationContextProvider restDocumentation) {
 		// tag::custom-encoding[]
 		this.mockMvc = MockMvcBuilders.webAppContextSetup(this.context)
-			.apply(documentationConfiguration(this.restDocumentation).snippets().withEncoding("ISO-8859-1"))
+			.apply(documentationConfiguration(restDocumentation).snippets().withEncoding("ISO-8859-1"))
 			.build();
 		// end::custom-encoding[]
 	}

docs/src/test/java/com/example/mockmvc/CustomFormat.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2023 the original author or authors.
+ * Copyright 2014-2025 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,34 +16,33 @@
 
 package com.example.mockmvc;
 
-import org.junit.Before;
-import org.junit.Rule;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.extension.ExtendWith;
 
 import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.restdocs.JUnitRestDocumentation;
+import org.springframework.restdocs.RestDocumentationContextProvider;
+import org.springframework.restdocs.RestDocumentationExtension;
 import org.springframework.restdocs.templates.TemplateFormats;
 import org.springframework.test.web.servlet.MockMvc;
 import org.springframework.test.web.servlet.setup.MockMvcBuilders;
 import org.springframework.web.context.WebApplicationContext;
 
 import static org.springframework.restdocs.mockmvc.MockMvcRestDocumentation.documentationConfiguration;
 
-public class CustomFormat {
-
-	@Rule
-	public final JUnitRestDocumentation restDocumentation = new JUnitRestDocumentation();
+@ExtendWith(RestDocumentationExtension.class)
+class CustomFormat {
 
 	@Autowired
 	private WebApplicationContext context;
 
 	@SuppressWarnings("unused")
 	private MockMvc mockMvc;
 
-	@Before
-	public void setUp() {
+	@BeforeEach
+	void setUp(RestDocumentationContextProvider restDocumentation) {
 		// tag::custom-format[]
 		this.mockMvc = MockMvcBuilders.webAppContextSetup(this.context)
-			.apply(documentationConfiguration(this.restDocumentation).snippets()
+			.apply(documentationConfiguration(restDocumentation).snippets()
 				.withTemplateFormat(TemplateFormats.markdown()))
 			.build();
 		// end::custom-format[]

docs/src/test/java/com/example/mockmvc/CustomUriConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2023 the original author or authors.
+ * Copyright 2014-2025 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,33 +16,32 @@
 
 package com.example.mockmvc;
 
-import org.junit.Before;
-import org.junit.Rule;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.extension.ExtendWith;
 
 import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.restdocs.JUnitRestDocumentation;
+import org.springframework.restdocs.RestDocumentationContextProvider;
+import org.springframework.restdocs.RestDocumentationExtension;
 import org.springframework.test.web.servlet.MockMvc;
 import org.springframework.test.web.servlet.setup.MockMvcBuilders;
 import org.springframework.web.context.WebApplicationContext;
 
 import static org.springframework.restdocs.mockmvc.MockMvcRestDocumentation.documentationConfiguration;
 
-public class CustomUriConfiguration {
-
-	@Rule
-	public final JUnitRestDocumentation restDocumentation = new JUnitRestDocumentation();
+@ExtendWith(RestDocumentationExtension.class)
+class CustomUriConfiguration {
 
 	@Autowired
 	private WebApplicationContext context;
 
 	@SuppressWarnings("unused")
 	private MockMvc mockMvc;
 
-	@Before
-	public void setUp() {
+	@BeforeEach
+	void setUp(RestDocumentationContextProvider restDocumentation) {
 		// tag::custom-uri-configuration[]
 		this.mockMvc = MockMvcBuilders.webAppContextSetup(this.context)
-			.apply(documentationConfiguration(this.restDocumentation).uris()
+			.apply(documentationConfiguration(restDocumentation).uris()
 				.withScheme("https")
 				.withHost("example.com")
 				.withPort(443))