Remove redundant junit-vintage-engine exclusion with Boot 2.4

Spring Boot 2.4 has switched from providing JUnit 5 in the test starter
(JUnit Jupiter and the JUnit Vintage Engine) to only providing JUnit
Jupiter. As such, the exclusion of junit-vintage-engine is no longer
required for projects that are using Spring Boot 2.4.

Closes gh-1095

initializr-generator-spring/src/main/java/io/spring/initializr/generator/spring/build/BuildProjectGenerationConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -49,7 +49,7 @@ public class BuildProjectGenerationConfiguration {
 	@Bean
 	@ConditionalOnPlatformVersion("[2.2.0.M3,2.2.0.M4]")
 	@Deprecated
-	public BuildCustomizer<Build> junitJupiterLegacyTestStarterContributor() {
+	public BuildCustomizer<Build> junit5LegacyTestStarterContributor() {
 		return (build) -> build.dependencies().add("test",
 				Dependency.withCoordinates("org.springframework.boot", "spring-boot-starter-test")
 						.scope(DependencyScope.TEST_COMPILE)
@@ -58,14 +58,22 @@ public class BuildProjectGenerationConfiguration {
 	}
 
 	@Bean
-	@ConditionalOnPlatformVersion("2.2.0.M5")
+	@ConditionalOnPlatformVersion("[2.2.0.M5,2.4.0-SNAPSHOT)")
-	public BuildCustomizer<Build> junitJupiterTestStarterContributor() {
+	public BuildCustomizer<Build> junit5TestStarterContributor() {
 		return (build) -> build.dependencies().add("test",
 				Dependency.withCoordinates("org.springframework.boot", "spring-boot-starter-test")
 						.scope(DependencyScope.TEST_COMPILE)
 						.exclusions(new Exclusion("org.junit.vintage", "junit-vintage-engine")));
 	}
 
+	@Bean
+	@ConditionalOnPlatformVersion("2.4.0-M1")
+	public BuildCustomizer<Build> junitJupiterTestStarterContributor() {
+		return (build) -> build.dependencies().add("test",
+				Dependency.withCoordinates("org.springframework.boot", "spring-boot-starter-test")
+						.scope(DependencyScope.TEST_COMPILE));
+	}
+
 	@Bean
 	public DefaultStarterBuildCustomizer defaultStarterContributor(InitializrMetadata metadata) {
 		return new DefaultStarterBuildCustomizer(metadata);

initializr-generator-spring/src/test/java/io/spring/initializr/generator/spring/build/gradle/GradleProjectGenerationConfigurationTests.java

@@ -181,6 +181,24 @@ class GradleProjectGenerationConfigurationTests {
 		assertThat(project).textFile("build.gradle").doesNotContain("exclude group");
 	}
 
+	@Test
+	void testStarterDoesNotExcludeVintageEngineWith24Snapshot() {
+		MutableProjectDescription description = new MutableProjectDescription();
+		description.setPlatformVersion(Version.parse("2.4.0-SNAPSHOT"));
+		description.setLanguage(new JavaLanguage());
+		ProjectStructure project = this.projectTester.generate(description);
+		assertThat(project).textFile("build.gradle").doesNotContain("exclude group");
+	}
+
+	@Test
+	void testStarterDoesNotExcludeVintageEngineWith24Milestone() {
+		MutableProjectDescription description = new MutableProjectDescription();
+		description.setPlatformVersion(Version.parse("2.4.0-M1"));
+		description.setLanguage(new JavaLanguage());
+		ProjectStructure project = this.projectTester.generate(description);
+		assertThat(project).textFile("build.gradle").doesNotContain("exclude group");
+	}
+
 	static Stream<Arguments> annotationProcessorScopeBuildParameters() {
 		return Stream.of(Arguments.arguments("1.5.17.RELEASE", false), Arguments.arguments("2.0.6.RELEASE", true),
 				Arguments.arguments("2.1.3.RELEASE", true));

initializr-generator-spring/src/test/java/io/spring/initializr/generator/spring/build/maven/MavenProjectGenerationConfigurationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -125,4 +125,22 @@ class MavenProjectGenerationConfigurationTests {
 		assertThat(project).textFile("pom.xml").doesNotContain("            <exclusions>");
 	}
 
+	@Test
+	void testStarterDoesNotExcludeVintageEngineWith24Snapshot() {
+		MutableProjectDescription description = new MutableProjectDescription();
+		description.setPlatformVersion(Version.parse("2.4.0-SNAPSHOT"));
+		description.setLanguage(new JavaLanguage());
+		ProjectStructure project = this.projectTester.generate(description);
+		assertThat(project).textFile("pom.xml").doesNotContain("            <exclusions>");
+	}
+
+	@Test
+	void testStarterDoesNotExcludeVintageEngineWith24Milestone() {
+		MutableProjectDescription description = new MutableProjectDescription();
+		description.setPlatformVersion(Version.parse("2.4.0-M1"));
+		description.setLanguage(new JavaLanguage());
+		ProjectStructure project = this.projectTester.generate(description);
+		assertThat(project).textFile("pom.xml").doesNotContain("            <exclusions>");
+	}
+
 }