Add buildSrc including build conventions plugins

Closes gh-1942

buildSrc/src/test/java/io/spring/gradle/TestKit.java

@@ -0,0 +1,58 @@
+/*
+ * Copyright 2002-2017 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. You may obtain a copy of
+ * the License at
+ *
+ * https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package io.spring.gradle;
+
+import org.apache.commons.io.FileUtils;
+import org.gradle.testkit.runner.GradleRunner;
+import org.junit.runner.Description;
+import org.junit.runners.model.Statement;
+
+import java.io.File;
+import java.io.IOException;
+import java.net.URISyntaxException;
+import java.net.URL;
+import java.nio.file.Paths;
+import java.util.Enumeration;
+
+public class TestKit {
+	final File buildDir;
+
+	public TestKit(File buildDir) {
+		this.buildDir = buildDir;
+	}
+
+	public File getRootDir() {
+		return buildDir;
+	}
+
+	public GradleRunner withProjectDir(File projectDir) throws IOException {
+		FileUtils.copyDirectory(projectDir, buildDir);
+		return GradleRunner.create()
+			.withProjectDir(buildDir)
+			.withPluginClasspath();
+	}
+
+	public GradleRunner withProjectResource(String projectResourceName) throws IOException, URISyntaxException {
+		ClassLoader classLoader = getClass().getClassLoader();
+		Enumeration<URL> resources = classLoader.getResources(projectResourceName);
+		if(!resources.hasMoreElements()) {
+			throw new IOException("Cannot find resource " + projectResourceName + " with " + classLoader);
+		}
+		URL resourceUrl = resources.nextElement();
+		File projectDir = Paths.get(resourceUrl.toURI()).toFile();
+		return withProjectDir(projectDir);
+	}
+}