Return unresolved when tests not found during discovery

Author: Neos3452

src/main/scala/org/scalatestplus/junit5/ScalaTestEngine.scala

@@ -21,11 +21,11 @@ import org.junit.platform.engine.support.descriptor.EngineDescriptor
 import org.junit.platform.engine.support.discovery.SelectorResolver.{Match, Resolution}
 import org.junit.platform.engine.support.discovery.{EngineDiscoveryRequestResolver, SelectorResolver}
 import org.junit.platform.engine.{EngineDiscoveryRequest, ExecutionRequest, TestDescriptor, TestExecutionResult, UniqueId}
-import org.scalatest.{Args, ConfigMap, DynaTags, Filter, ParallelTestExecution, Stopper, Suite, Tracker}
+import org.scalatest.{Args, ConfigMap, DynaTags, Filter, ParallelTestExecution, Stopper, Tracker}
 
 import java.lang.reflect.Modifier
 import java.util.concurrent.atomic.AtomicInteger
-import java.util.{Optional, UUID}
+import java.util.Optional
 import java.util.concurrent.{ExecutorService, Executors, ThreadFactory}
 import java.util.logging.Logger
 import java.util.stream.Collectors
@@ -107,7 +107,11 @@ class ScalaTestEngine extends org.junit.platform.engine.TestEngine {
               .stream()
               .flatMap(addToParentFunction(context))
               .collect(Collectors.toSet())
-          Resolution.matches(matches)
+          if (matches.isEmpty) {
+            Resolution.unresolved()
+          } else {
+            Resolution.matches(matches)
+          }
         }
 
         override def resolve(selector: PackageSelector, context: SelectorResolver.Context): SelectorResolver.Resolution = {
@@ -116,7 +120,11 @@ class ScalaTestEngine extends org.junit.platform.engine.TestEngine {
               .stream()
               .flatMap(addToParentFunction(context))
               .collect(Collectors.toSet())
-          Resolution.matches(matches)
+          if (matches.isEmpty) {
+            Resolution.unresolved()
+          } else {
+            Resolution.matches(matches)
+          }
         }
 
         override def resolve(selector: ModuleSelector, context: SelectorResolver.Context): SelectorResolver.Resolution = {
@@ -125,7 +133,11 @@ class ScalaTestEngine extends org.junit.platform.engine.TestEngine {
               .stream()
               .flatMap(addToParentFunction(context))
               .collect(Collectors.toSet())
-          Resolution.matches(matches)
+          if (matches.isEmpty) {
+            Resolution.unresolved()
+          } else {
+            Resolution.matches(matches)
+          }
         }
 
         override def resolve(selector: ClassSelector, context: SelectorResolver.Context): SelectorResolver.Resolution = {

src/test/scala/org/scalatestplus/junit5/ScalaTestEngineSpec.scala

@@ -0,0 +1,65 @@
+package org.scalatestplus.junit5
+
+import org.junit.platform.engine.UniqueId
+import org.junit.platform.engine.discovery.ClasspathRootSelector
+import org.junit.platform.engine.discovery.DiscoverySelectors.{selectClasspathRoots, selectPackage}
+import org.junit.platform.launcher.core.LauncherDiscoveryRequestBuilder.request
+import org.scalatest.{BeforeAndAfterAll, funspec}
+import org.scalatestplus.junit5.helpers.HappySuite
+
+import java.nio.file.{Files, Paths}
+import scala.collection.JavaConverters._
+
+class ScalaTestEngineSpec extends funspec.AnyFunSpec with BeforeAndAfterAll {
+  val engine = new ScalaTestEngine
+  var scalaTestEngineProperty: Option[String] = None
+
+  override def beforeAll(): Unit = {
+    scalaTestEngineProperty = Option(System.clearProperty("org.scalatestplus.junit5.ScalaTestEngine.disabled"))
+  }
+
+  override def afterAll(): Unit = {
+    scalaTestEngineProperty.foreach(System.setProperty("org.scalatestplus.junit5.ScalaTestEngine.disabled", _))
+  }
+
+  describe("ScalaTestEngine") {
+    describe("discover method") {
+      it("should discover suites on classpath") {
+        val classPathRoot = classOf[ScalaTestEngineSpec].getProtectionDomain.getCodeSource.getLocation
+        val discoveryRequest = request.selectors(
+          selectClasspathRoots(java.util.Collections.singleton(Paths.get(classPathRoot.toURI)))
+        ).build()
+        val engineDescriptor = engine.discover(discoveryRequest, UniqueId.forEngine(engine.getId()))
+        assert(engineDescriptor.getChildren.asScala.exists(td => td.asInstanceOf[ScalaTestClassDescriptor].suiteClass == classOf[HappySuite]))
+      }
+
+      it("should return unresolved for classpath without any tests") {
+        val emptyPath = Files.createTempDirectory(null)
+        val discoveryRequest = request.selectors(
+          selectClasspathRoots(java.util.Collections.singleton(emptyPath))
+        ).build()
+
+        val engineDescriptor = engine.discover(discoveryRequest, UniqueId.forEngine(engine.getId()))
+        assert(engineDescriptor.getChildren.asScala.isEmpty)
+      }
+
+      it("should discover suites in package") {
+        val discoveryRequest = request.selectors(
+          selectPackage("org.scalatestplus.junit5.helpers")
+        ).build()
+
+        val engineDescriptor = engine.discover(discoveryRequest, UniqueId.forEngine(engine.getId()))
+        assert(engineDescriptor.getChildren.asScala.exists(td => td.asInstanceOf[ScalaTestClassDescriptor].suiteClass == classOf[HappySuite]))
+      }
+
+      it("should return unresolved for package without any tests") {
+        val discoveryRequest = request.selectors(
+          selectPackage("org.scalatestplus.junit5.nonexistant")
+        ).build()
+
+        val engineDescriptor = engine.discover(discoveryRequest, UniqueId.forEngine(engine.getId()))
+        assert(engineDescriptor.getChildren.asScala.isEmpty)
+      }
+    }
+  }
+}