Skip dependency exclusions if groupId is null

Fixes gh-1133

spring-boot-integration-tests/src/test/java/org/springframework/boot/gradle/FlatdirTests.java

@@ -0,0 +1,61 @@
+/*
+ * Copyright 2012-2014 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
+ *
+ *      http://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 org.springframework.boot.gradle;
+
+import java.io.File;
+
+import org.gradle.tooling.ProjectConnection;
+import org.junit.Before;
+import org.junit.Test;
+import org.springframework.boot.dependency.tools.ManagedDependencies;
+import org.springframework.util.FileCopyUtils;
+import org.springframework.util.FileSystemUtils;
+
+/**
+ * Tests for using the Gradle plugin's support for flat directory repos
+ *
+ * @author Dave Syer
+ */
+public class FlatdirTests {
+
+	private ProjectConnection project;
+
+	private File libs = new File("target/flatdir/lib");
+
+	private static final String BOOT_VERSION = ManagedDependencies.get().find(
+			"spring-boot").getVersion();
+	
+	@Before
+	public void init() {
+		if (libs.exists()) {
+			FileSystemUtils.deleteRecursively(libs);
+		}
+	}
+
+	@Test
+	public void flatdir() throws Exception {
+		project = new ProjectCreator().createProject("flatdir");
+		if (!libs.exists()) {
+			libs.mkdirs();
+		}
+		FileCopyUtils.copy(new File("src/test/resources/foo.jar"),
+				new File(libs, "foo-1.0.0.jar"));
+		project.newBuild().forTasks("build").withArguments(
+				"-PbootVersion=" + BOOT_VERSION, "--stacktrace").run();
+	}
+
+}