Add simple integration tests for the plugin

build.gradle

@@ -4,6 +4,7 @@ plugins {
 	id 'java-gradle-plugin'
 	id 'idea'
 	id 'eclipse'
+	id 'groovy'
 }
 
 sourceCompatibility = 1.8
@@ -54,6 +55,9 @@ dependencies {
 	// source code remapping
 	implementation ('org.cadixdev:mercury:0.1.0.fabric-SNAPSHOT')
 
+	// Testing
+	testImplementation(gradleTestKit())
+	testImplementation("org.spockframework:spock-core:1.3-groovy-2.5")
 }
 
 jar {
@@ -78,10 +82,6 @@ license {
 	exclude '**/loom/util/DownloadUtil.java'
 }
 
-task wrapper(type: Wrapper) {
-	gradleVersion = '4.10.2'
-}
-
 gradlePlugin {
 	plugins {
 		register("fabricLoom") {
@@ -99,7 +99,7 @@ publishing {
 			version project.version
 
 			from components["java"]
-	
+
 			artifact sourcesJar
 			artifact javadocJar
 		}

src/test/groovy/net/fabricmc/loom/EmptyBuildFunctionalTest.groovy

@@ -0,0 +1,153 @@
+package net.fabricmc.loom
+
+import org.gradle.testkit.runner.GradleRunner
+import org.junit.Rule
+import org.junit.rules.TemporaryFolder
+import spock.lang.Specification
+import spock.lang.Unroll
+
+import static org.gradle.testkit.runner.TaskOutcome.SUCCESS
+
+/**
+ * Created by Mitchell Skaggs on 6/10/2019.
+ */
+class EmptyBuildFunctionalTest extends Specification {
+	@Rule
+	TemporaryFolder testProjectDir = new TemporaryFolder()
+	File settingsFile
+	File buildFile
+	File propsFile
+
+	def setup() {
+		settingsFile = testProjectDir.newFile('settings.gradle')
+		buildFile = testProjectDir.newFile('build.gradle')
+		propsFile = testProjectDir.newFile('gradle.properties')
+	}
+
+	@Unroll
+	def "empty build succeeds using Minecraft #mcVersion"() {
+		given:
+		settingsFile << """
+rootProject.name = 'empty-build-functional-test'
+"""
+
+		propsFile << """
+org.gradle.caching=true
+org.gradle.parallel=true
+
+# Fabric Properties
+# check these on https://fabricmc.net/use
+minecraft_version=$mcVersion
+yarn_mappings=$yarnVersion
+loader_version=$loaderVersion
+
+# Mod Properties
+mod_version = 1.0.0
+maven_group = net.fabricmc
+archives_base_name = fabric-example-mod
+
+# Dependencies
+# currently not on the main fabric site, check on the maven: https://maven.fabricmc.net/net/fabricmc/fabric
+fabric_version=$fabricVersion
+"""
+
+		buildFile << """
+plugins {
+	id 'fabric-loom'
+	id 'maven-publish'
+}
+sourceCompatibility = JavaVersion.VERSION_1_8
+targetCompatibility = JavaVersion.VERSION_1_8
+
+archivesBaseName = project.archives_base_name
+version = project.mod_version
+group = project.maven_group
+
+minecraft {
+}
+
+dependencies {
+	//to change the versions see the gradle.properties file
+	minecraft "com.mojang:minecraft:\${project.minecraft_version}"
+	mappings "net.fabricmc:yarn:\${project.yarn_mappings}"
+	modCompile "net.fabricmc:fabric-loader:\${project.loader_version}"
+
+	// Fabric API. This is technically optional, but you probably want it anyway.
+	modCompile "net.fabricmc.fabric-api:fabric-api:\${project.fabric_version}"
+
+	// PSA: Some older mods, compiled on Loom 0.2.1, might have outdated Maven POMs.
+	// You may need to force-disable transitiveness on them.
+}
+
+processResources {
+	inputs.property "version", project.version
+
+	from(sourceSets.main.resources.srcDirs) {
+		include "fabric.mod.json"
+		expand "version": project.version
+	}
+
+	from(sourceSets.main.resources.srcDirs) {
+		exclude "fabric.mod.json"
+	}
+}
+
+// ensure that the encoding is set to UTF-8, no matter what the system default is
+// this fixes some edge cases with special characters not displaying correctly
+// see http://yodaconditions.net/blog/fix-for-java-file-encoding-problems-with-gradle.html
+tasks.withType(JavaCompile) {
+	options.encoding = "UTF-8"
+}
+
+// Loom will automatically attach sourcesJar to a RemapSourcesJar task and to the "build" task
+// if it is present.
+// If you remove this task, sources will not be generated.
+task sourcesJar(type: Jar, dependsOn: classes) {
+	classifier = "sources"
+	from sourceSets.main.allSource
+}
+
+jar {
+	from "LICENSE"
+}
+
+// configure the maven publication
+publishing {
+	publications {
+		mavenJava(MavenPublication) {
+			// add all the jars that should be included when publishing to maven
+			artifact(jar) {
+				builtBy remapJar
+			}
+			artifact(sourcesJar) {
+				builtBy remapSourcesJar
+			}
+		}
+	}
+
+	// select the repositories you want to publish to
+	repositories {
+		// uncomment to publish to the local maven
+		// mavenLocal()
+	}
+}
+"""
+
+		when:
+		def result = GradleRunner.create()
+				.withProjectDir(testProjectDir.root)
+				.withArguments('build')
+				.withPluginClasspath()
+				.build()
+
+		then:
+		//result.output.contains('Hello world!')
+		result.task(":build").outcome == SUCCESS
+
+		where:
+		mcVersion | yarnVersion       | loaderVersion     | fabricVersion
+		'1.14'    | '1.14+build.21'   | '0.4.8+build.155' | '0.3.0+build.183'
+		'1.14.1'  | '1.14.1+build.10' | '0.4.8+build.155' | '0.3.0+build.183'
+		'1.14.2'  | '1.14.2+build.7'  | '0.4.8+build.155' | '0.3.0+build.183'
+	}
+}