/*
 * Copyright OpenSearch Contributors
 * SPDX-License-Identifier: Apache-2.0
 */

/**
 * OpenSearch Plugin build tools don't work with the Gradle Jacoco Plugin to report coverage out of the box.
 * https://github.com/elastic/elasticsearch/issues/28867.
 *
 * This code sets up coverage reporting manually for OpenSearch plugin tests. This is complicated because:
 *  1. The OpenSearch integTest Task doesn't implement Gradle's JavaForkOptions so we have to manually start the jacoco agent with the test JVM
 *  2. The cluster nodes are stopped using 'kill -9' which means jacoco can't dump it's execution output to a file on VM shutdown
 *  3. The Java Security Manager prevents JMX from writing execution output to the file.
 *
 *  To workaround these we start the cluster with jmx enabled and then use Jacoco's JMX MBean to get the execution data before the
 *  cluster is stopped and dump it to a file. Luckily our current security policy seems to allow this. This will also probably
 *  break if there are multiple nodes in the integTestCluster. But for now... it sorta works. 
 */
apply plugin: 'jacoco'

// Get gradle to generate the required jvm agent arg for us using a dummy tasks of type Test. Unfortunately Elastic's
// testing tasks don't derive from Test so the jacoco plugin can't do this automatically.
def jacocoDir = "${buildDir}/jacoco"
task dummyTest(type: Test) {
    enabled = false
    workingDir = file("/") // Force absolute path to jacoco agent jar
    jacoco {
        destinationFile = file("${jacocoDir}/test.exec")
        destinationFile.parentFile.mkdirs()
        jmx = true
    }
}

jacocoTestReport {
    dependsOn test
    executionData dummyTest.jacoco.destinationFile
    getSourceDirectories().from(sourceSets.main.allSource)
    getClassDirectories().from(sourceSets.main.output)
    reports {
        html.required = true // human readable
        xml.required = true // for coverlay
    }
}

project.gradle.projectsEvaluated {
    jacocoTestReport.dependsOn test
}

check.dependsOn jacocoTestReport