Add failing test to highlight paths issue

Fails with:
```
ERROR: IO problem while reading files with API signatures: java.io.FileNotFoundException: /home/alpar/work/elastic/elasticsearch/buildSrc/src/testKit/forbidden-apis/buildSrc/src/main/resources/forbidden/jdk-signatures.txt (No such file or directory)
```
because signature definitiions are accessed on the FS directly.

Author: alpar-t

buildSrc/src/test/java/org/elasticsearch/gradle/precommit/ForbiddenApisCLITaskIT.java

@@ -0,0 +1,34 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you 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.elasticsearch.gradle.precommit;
+
+import org.elasticsearch.gradle.test.GradleIntegrationTestCase;
+import org.gradle.testkit.runner.BuildResult;
+
+public class ForbiddenApisCLITaskIT extends GradleIntegrationTestCase {
+
+    private static final String SAMPLE_PROJECT = "forbidden-apis";
+
+    public void testRunCliTask() {
+        BuildResult result = getGradleRunner(SAMPLE_PROJECT)
+            .withArguments("forbiddenApisCli", "-s")
+            .build();
+    }
+
+}

buildSrc/src/test/java/org/elasticsearch/gradle/precommit/NamingConventionsTaskIT.java

@@ -2,18 +2,17 @@
 
 import org.elasticsearch.gradle.test.GradleIntegrationTestCase;
 import org.gradle.testkit.runner.BuildResult;
-import org.gradle.testkit.runner.GradleRunner;
 import org.gradle.testkit.runner.TaskOutcome;
 
 import java.util.Arrays;
 
 public class NamingConventionsTaskIT extends GradleIntegrationTestCase {
 
+    public static final String SAMPLE_PROJECT = "namingConventionsSelfTest";
+
     public void testPluginCanBeApplied() {
-        BuildResult result = GradleRunner.create()
-            .withProjectDir(getProjectDir("namingConventionsSelfTest"))
+        BuildResult result = getGradleRunner(SAMPLE_PROJECT)
             .withArguments("hello", "-s", "-PcheckForTestsInMain=false")
-            .withPluginClasspath()
             .build();
 
         assertEquals(TaskOutcome.SUCCESS, result.task(":hello").getOutcome());
@@ -22,10 +21,8 @@ public void testPluginCanBeApplied() {
     }
 
     public void testNameCheckFailsAsItShould() {
-        BuildResult result = GradleRunner.create()
-            .withProjectDir(getProjectDir("namingConventionsSelfTest"))
+        BuildResult result = getGradleRunner(SAMPLE_PROJECT)
             .withArguments("namingConventions", "-s", "-PcheckForTestsInMain=false")
-            .withPluginClasspath()
             .buildAndFail();
 
         assertNotNull("task did not run", result.task(":namingConventions"));
@@ -47,10 +44,8 @@ public void testNameCheckFailsAsItShould() {
     }
 
     public void testNameCheckFailsAsItShouldWithMain() {
-        BuildResult result = GradleRunner.create()
-            .withProjectDir(getProjectDir("namingConventionsSelfTest"))
+        BuildResult result = getGradleRunner(SAMPLE_PROJECT)
             .withArguments("namingConventions", "-s", "-PcheckForTestsInMain=true")
-            .withPluginClasspath()
             .buildAndFail();
 
         assertNotNull("task did not run", result.task(":namingConventions"));

buildSrc/src/test/java/org/elasticsearch/gradle/test/GradleIntegrationTestCase.java

@@ -1,5 +1,7 @@
 package org.elasticsearch.gradle.test;
 
+import org.gradle.testkit.runner.GradleRunner;
+
 import java.io.File;
 
 public abstract class GradleIntegrationTestCase extends GradleUnitTestCase {
@@ -13,4 +15,14 @@ protected File getProjectDir(String name) {
         return new File(root, name);
     }
 
+    protected GradleRunner getGradleRunner(String sampleProject) {
+        return GradleRunner.create()
+            .withProjectDir(getProjectDir(sampleProject))
+            .withPluginClasspath(
+                //Collections.singleton(
+                //    new File("/home/alpar/work/elastic/elasticsearch/buildSrc/build/pluginUnderTestMetaDataWithJar/")
+                //)
+            );
+    }
+
 }

buildSrc/src/testKit/forbidden-apis/build.gradle

@@ -0,0 +1,7 @@
+plugins {
+    id 'java'
+    id 'elasticsearch.build'
+}
+
+ext.licenseFile = file("$buildDir/dummy/license")
+ext.noticeFile = file("$buildDir/dummy/notice")

buildSrc/src/testKit/forbidden-apis/src/main/java/org/elasticsearch/test/UnsafeImplementationClass.java

@@ -0,0 +1,28 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you 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.elasticsearch.test;
+
+
+public class UnsafeImplementationClass {
+
+    public UnsafeImplementationClass() {
+
+    }
+}