[Native][tests] Remove unnecesary common prefix in dynamic test names

native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/AbstractNativeBlackBoxTest.kt

@@ -68,22 +68,24 @@ abstract class AbstractNativeBlackBoxTest {
      * This function should be called from a method annotated with [org.junit.jupiter.api.TestFactory].
      */
     internal fun dynamicTestCase(testCaseId: TestCaseId): Collection<DynamicNode> {
-        val rootTestRunNode = testRunProvider.getTestRuns(testCaseId)
-        return buildJUnitDynamicNodes(rootTestRunNode)
+        val testRunNodes = testRunProvider.getTestRuns(testCaseId)
+        return buildJUnitDynamicNodes(testRunNodes)
     }
 
     // We have to use planar (one-level) tree of JUnit5 dynamic nodes, because Gradle does not support yet rendering
     // tests with arbitrary nesting level in their test reports. As long as these reports are consumed by various CI (such as TeamCity)
     // we have almost no chance to display test results in CI properly.
-    private fun buildJUnitDynamicNodes(testRunNode: TreeNode<TestRun>): Collection<DynamicNode> =
+    private fun buildJUnitDynamicNodes(testRunNodes: Collection<TreeNode<TestRun>>): Collection<DynamicNode> =
     // This is the proper implementation that should be used instead:
 //        buildList {
-//            testRunNode.items.mapTo(this) { testRun ->
-//                dynamicTest(testRun.displayName) { runTest(testRun) }
-//            }
+//            testRunNodes.forEach { testRunNode ->
+//                testRunNode.items.mapTo(this) { testRun ->
+//                    dynamicTest(testRun.displayName) { runTest(testRun) }
+//                }
 //
-//            testRunNode.children.mapTo(this) { childTestRunNode ->
-//                dynamicContainer(childTestRunNode.packageSegment, buildJUnitDynamicNodes(childTestRunNode))
+//                testRunNode.children.mapTo(this) { childTestRunNode ->
+//                    dynamicContainer(childTestRunNode.packageSegment, buildJUnitDynamicNodes(childTestRunNode))
+//                }
 //            }
 //        }
         buildList {
@@ -97,7 +99,7 @@ abstract class AbstractNativeBlackBoxTest {
                 children.forEach { it.processItems(ownPackageSegment) }
             }
 
-            testRunNode.processItems("")
+            testRunNodes.forEach { testRunNode -> testRunNode.processItems("") }
         }
 
     private fun performTestRun(testRun: TestRun) {

native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/support/TestRunProvider.kt

@@ -98,7 +98,9 @@ internal class TestRunProvider(
      *       }
      *   }
      */
-    fun getTestRuns(testCaseId: TestCaseId): TreeNode<TestRun> = withTestExecutable(testCaseId) { testCase, executable, cacheKey ->
+    fun getTestRuns(
+        testCaseId: TestCaseId
+    ): Collection<TreeNode<TestRun>> = withTestExecutable(testCaseId) { testCase, executable, cacheKey ->
         fun createTestRun(testRunName: String, testFunction: TestFunction?): TestRun {
             val runParameters = getRunParameters(testCase, testFunction)
             return TestRun(testRunName, executable, runParameters, testCase.id)

native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/support/util/TreeNode.kt

@@ -15,15 +15,15 @@ internal interface TreeNode<T> {
     companion object {
         fun <T> oneLevel(vararg items: T) = oneLevel(listOf(*items))
 
-        fun <T> oneLevel(items: Iterable<T>) = object : TreeNode<T> {
+        fun <T> oneLevel(items: Iterable<T>): List<TreeNode<T>> = listOf(object : TreeNode<T> {
             override val packageSegment get() = ""
             override val items = items.toList()
             override val children get() = emptyList<TreeNode<T>>()
-        }
+        })
     }
 }
 
-internal fun <T, R> Collection<T>.buildTree(extractPackageName: (T) -> PackageFQN, transform: (T) -> R): TreeNode<R> {
+internal fun <T, R> Collection<T>.buildTree(extractPackageName: (T) -> PackageFQN, transform: (T) -> R): Collection<TreeNode<R>> {
     val groupedItems: Map<PackageFQN, List<R>> = groupBy(extractPackageName).mapValues { (_, items) -> items.map(transform) }
 
     // Fast pass.
@@ -44,8 +44,14 @@ internal fun <T, R> Collection<T>.buildTree(extractPackageName: (T) -> PackageFQ
         node.items += items
     }
 
-    // Skip meaningless nodes starting from the root. Compress the resulting tree.
-    return root.skipMeaninglessNodes().apply { compress() }
+    // Skip meaningless nodes starting from the root.
+    val meaningfulNode = root.skipMeaninglessNodes().apply { compress() }
+
+    // Compress the resulting tree.
+    return if (meaningfulNode.items.isNotEmpty() || meaningfulNode.childrenMap.isEmpty())
+        listOf(meaningfulNode)
+    else
+        meaningfulNode.childrenMap.values
 }
 
 private class TreeBuilder<T>(override var packageSegment: String) : TreeNode<T> {