JUnit5 framework: Support fields declared in parent class.

Although inheritance is not recommended and even redundant with JUnit5 extensions, we still have to support it.


Merge-request: IJ-MR-139345
Merged-by: Ilya Kazakevich <ilya.kazakevich@jetbrains.com>

GitOrigin-RevId: 812e828c2c4232fd7dd92bafe58001d78497fd48

platform/testFramework/junit5/src/fixture/TestFixtureExtension.kt

@@ -5,8 +5,10 @@ import com.intellij.platform.util.coroutines.childScope
 import kotlinx.coroutines.*
 import org.jetbrains.annotations.TestOnly
 import org.junit.jupiter.api.extension.*
-import java.lang.reflect.Field
+import org.junit.platform.commons.support.HierarchyTraversalMode
+import org.junit.platform.commons.support.ReflectionSupport
 import java.lang.reflect.Modifier
+import java.util.function.Predicate
 import kotlin.jvm.optionals.getOrNull
 
 @TestOnly
@@ -30,13 +32,10 @@ internal class TestFixtureExtension : BeforeAllCallback,
     @OptIn(DelicateCoroutinesApi::class)
     val testScope = GlobalScope.childScope(context.displayName)
     val pendingFixtures = ArrayList<Deferred<*>>()
-    for (field: Field in testClass.declaredFields) {
-      if (!TestFixture::class.java.isAssignableFrom(field.type)) {
-        continue
-      }
-      if (Modifier.isStatic(field.modifiers) != static) {
-        continue
-      }
+    val fields = ReflectionSupport.findFields(testClass, Predicate { field ->
+      TestFixture::class.java.isAssignableFrom(field.type) && Modifier.isStatic(field.modifiers) == static
+    }, HierarchyTraversalMode.TOP_DOWN)
+    for (field in fields) {
       field.isAccessible = true
       val fixture = field.get(testInstance) as TestFixtureImpl<*>
       pendingFixtures.add(fixture.init(testScope, context.uniqueId))

platform/testFramework/junit5/test/showcase/JUnit5InheritanceFixture.kt

@@ -0,0 +1,37 @@
+// Copyright 2000-2024 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+package com.intellij.testFramework.junit5.showcase
+
+import com.intellij.testFramework.junit5.TestApplication
+import com.intellij.testFramework.junit5.fixture.disposableFixture
+import com.intellij.testFramework.junit5.fixture.moduleFixture
+import com.intellij.testFramework.junit5.fixture.projectFixture
+import org.junit.jupiter.api.Assertions.assertNotNull
+import org.junit.jupiter.api.Test
+
+/**
+ * Support fields declared at parent level.
+ * Implementation inheritance is a bad pattern, avoid it and use extensions instead
+ */
+@TestApplication
+open class AbstractTestCase {
+  companion object {
+    val classLevelDisposable = disposableFixture()
+  }
+
+  protected val testLevelProject = projectFixture()
+}
+
+class JUnit5InheritanceFixture : AbstractTestCase() {
+  private val moduleFixture = testLevelProject.moduleFixture()
+
+  @Test
+  fun ensureParentFixturesInitialized() {
+    assertNotNull(classLevelDisposable.get())
+    assertNotNull(testLevelProject.get())
+  }
+
+  @Test
+  fun ensureChildrenInheritParent() {
+    assertNotNull(moduleFixture.get())
+  }
+}