gradle, produce jacoco coverage report, html

build.gradle.kts

@@ -1,4 +1,5 @@
 plugins {
+  id("jacoco")
   id("java")
   id("maven-publish")
 }
@@ -64,6 +65,7 @@ tasks.test {
     includeEngines("junit-jupiter")
     includeEngines("junit-vintage")
   }
+  finalizedBy(tasks.jacocoTestReport) // report is always generated after tests run
 }
 
 // make all archive tasks in the build reproducible
@@ -72,3 +74,12 @@ tasks.withType<AbstractArchiveTask>().configureEach {
   isReproducibleFileOrder = true
 }
 
+tasks.jacocoTestReport {
+  dependsOn(tasks.test) // tests are required to run before generating the report
+  reports {
+    xml.isEnabled = false
+    csv.isEnabled = false
+    html.destination = file("${buildDir}/jacocoHtml")
+  }
+}
+