Allow converting junit test to scalameter benchmark

Lets start tracking performance!

To run benchmarks execute `dotty-bench/test:run` in sbt

1 files changed, 61 insertions, 0 deletions

diff --git a/bench/src/test/scala/TestsAsBenchmarks.scala b/bench/src/test/scala/TestsAsBenchmarks.scala
new file mode 100644
index 000000000..a078c9f78
--- /dev/null
+++ b/bench/src/test/scala/TestsAsBenchmarks.scala
@@ -0,0 +1,61 @@
+package dotty.tools.benchmarks
+
+import java.lang.annotation.Annotation
+import java.lang.reflect.Method
+
+import org.junit.runner.Request
+import org.junit.runner.notification.RunNotifier
+import org.scalameter.PerformanceTest.OnlineRegressionReport
+import org.scalameter.api._
+import org.scalameter.reporting.RegressionReporter.Tester
+
+import scala.collection.mutable.ListBuffer
+
+
+abstract class TestsToBenchmarkConverter
+(targetClass: Class[_],
+ filterAnnot: Class[_ <: java.lang.annotation.Annotation] = classOf[org.junit.Test].asInstanceOf[Class[_ <: java.lang.annotation.Annotation]])
+  extends OnlineRegressionReport {
+
+  // accept all the results, do not fail
+  override def tester: Tester = new Tester.Accepter
+
+  override def executor: Executor = LocalExecutor(warmer, aggregator, measurer)
+  val testNames = getMethodsAnnotatedWith(targetClass, filterAnnot).map(_.getName).sorted
+
+
+  val tests = testNames.map{name =>
+    val runner = Request.method(targetClass, name).getRunner
+    (name, Gen.single("test")(name).map(Request.method(targetClass, _).getRunner))}.toMap
+  //Gen.enumeration("test")(testNames:_*)
+
+  performance of targetClass.getSimpleName config (Context(reports.resultDir -> "./tmp")) in {
+    for (test <- testNames)
+      measure.method(test) in {
+        using(tests(test)) curve test in {
+          r =>
+            val dummy = new RunNotifier()
+            r.run(dummy)
+        }
+      }
+  }
+
+  def getMethodsAnnotatedWith(clazz: Class[_], annotation: Class[_ <: java.lang.annotation.Annotation]): List[Method] = {
+    val methods = ListBuffer[Method]()
+    var klass: Class[_] = clazz
+    while (klass ne classOf[AnyRef]) {
+      val allMethods = klass.getDeclaredMethods
+      import scala.collection.JavaConversions._
+      for (method <- allMethods) {
+        if (annotation == null || method.isAnnotationPresent(annotation)) {
+          val annotInstance: Annotation = method.getAnnotation(annotation)
+          methods.add(method)
+        }
+      }
+      klass = klass.getSuperclass
+    }
+    methods.toList
+  }
+}
+
+object dotcTests extends TestsToBenchmarkConverter(classOf[dotc.tests])