Build: Add build plugin for "messy" tests

We have some tests which have crazy dependencies, like on other plugins.
This change adds a "messy-test" gradle plugin which can be used for qa
projects that these types of tests can run in. What this adds over
regular standalone tests is the plugin properties and metadata on the
classpath, so that the plugins are properly initialized.

buildSrc/src/main/groovy/org/elasticsearch/gradle/test/ClusterFormationTasks.groovy

@@ -525,7 +525,7 @@ class ClusterFormationTasks {
         }
     }
 
-    static String pluginTaskName(String action, String name, String suffix) {
+    public static String pluginTaskName(String action, String name, String suffix) {
         // replace every dash followed by a character with just the uppercase character
         String camelName = name.replaceAll(/-(\w)/) { _, c -> c.toUpperCase(Locale.ROOT) }
         return action + camelName[0].toUpperCase(Locale.ROOT) + camelName.substring(1) + suffix

buildSrc/src/main/groovy/org/elasticsearch/gradle/test/MessyTestPlugin.groovy

@@ -0,0 +1,63 @@
+/*
+ * 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.test
+
+import org.elasticsearch.gradle.plugin.PluginBuildPlugin
+import org.gradle.api.Project
+import org.gradle.api.artifacts.Dependency
+import org.gradle.api.artifacts.ProjectDependency
+import org.gradle.api.tasks.Copy
+
+/**
+ * A plugin to run messy tests, which are generally tests that depend on plugins.
+ *
+ * This plugin will add the same test configuration as standalone tests, except
+ * also add the plugin-metadata and properties files for each plugin project
+ * dependency.
+ */
+class MessyTestPlugin extends StandaloneTestPlugin {
+    @Override
+    public void apply(Project project) {
+        super.apply(project)
+
+        project.configurations.testCompile.dependencies.all { Dependency dep ->
+            // this closure is run every time a compile dependency is added
+            if (dep instanceof ProjectDependency && dep.dependencyProject.plugins.hasPlugin(PluginBuildPlugin)) {
+                project.gradle.projectsEvaluated {
+                    addPluginResources(project, dep.dependencyProject)
+                }
+            }
+        }
+    }
+
+    private static addPluginResources(Project project, Project pluginProject) {
+        String outputDir = "generated-resources/${pluginProject.name}"
+        String taskName = ClusterFormationTasks.pluginTaskName("copy", pluginProject.name, "Metadata")
+        Copy copyPluginMetadata = project.tasks.create(taskName, Copy.class)
+        copyPluginMetadata.into(outputDir)
+        copyPluginMetadata.from(pluginProject.tasks.pluginProperties)
+        copyPluginMetadata.from(pluginProject.file('src/main/plugin-metadata'))
+        project.sourceSets.test.output.dir(outputDir, builtBy: taskName)
+
+        // add each generated dir to the test classpath in IDEs
+        //project.eclipse.classpath.sourceSets = [project.sourceSets.test]
+        project.idea.module.singleEntryLibraries= ['TEST': [project.file(outputDir)]]
+    }
+}

buildSrc/src/main/resources/META-INF/gradle-plugins/elasticsearch.messy-test.properties

@@ -0,0 +1,20 @@
+#
+# 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.
+#
+
+implementation-class=org.elasticsearch.gradle.test.MessyTestPlugin