Add new option to allow full delegation of tests to gradle in IntelliJ plus docs

Author: lukewhiting

CONTRIBUTING.md

@@ -206,6 +206,18 @@ Alternative manual steps for IntelliJ.
    3. Navigate to the file `build-conventions/formatterConfig.xml`
    4. Click "OK"
 
+#### Options
+
+When importing to IntelliJ, we offer a few options that can be used to
+configure the behaviour of the import:
+
+| Property                                   | Description                                                                                          | Values (* = default) |
+|--------------------------------------------|------------------------------------------------------------------------------------------------------|----------------------|
+| `org.elasticsearch.idea-configuration-cache` | Should IntelliJ enable the Gradle Configuration cache to speed up builds when generating run configs | *`ture`, `false`         |
+| `org.elasticsearch.idea-delegate-to-gradle`  | Should IntelliJ use Gradle for all generated run / test configs or prompt each time                  | `true`, *`false`         |
+
+These options can be set anywhere on the Gradle config path including in `~/.gradle/gradle.settings`
+
 ### REST endpoint conventions
 
 Elasticsearch typically uses singular nouns rather than plurals in URLs.

build-tools-internal/src/main/groovy/elasticsearch.ide.gradle

@@ -180,6 +180,7 @@ if (providers.systemProperty('idea.active').getOrNull() == 'true') {
   // this path is produced by the extractLibs task above
   String testLibraryPath = TestUtil.getTestLibraryPath("${elasticsearchProject.left()}/libs/native/libraries/build/platform")
   def enableIdeaCC = providers.gradleProperty("org.elasticsearch.idea-configuration-cache").getOrElse("true").toBoolean()
+  def delegateToGradle = providers.gradleProperty("org.elasticsearch.idea-delegate-to-gradle").getOrElse("false").toBoolean()
   idea {
     project {
       vcs = 'Git'
@@ -188,7 +189,7 @@ if (providers.systemProperty('idea.active').getOrNull() == 'true') {
       settings {
         delegateActions {
           delegateBuildRunToGradle = false
-          testRunner = 'choose_per_test'
+          testRunner = delegateToGradle ? 'gradle' : 'choose_per_test'
         }
         taskTriggers {
           afterSync tasks.named('configureIdeCheckstyle'),