add base class for JUnit 4.x tests

GitOrigin-RevId: bcc6129dec68d228a0b200068ff9d4a7e489fecf

java/testFramework/src/com/intellij/testFramework/fixtures/LightJavaCodeInsightFixtureTestCase4.kt

@@ -0,0 +1,52 @@
+// Copyright 2000-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+package com.intellij.testFramework.fixtures
+
+import com.intellij.testFramework.EdtRule
+import com.intellij.testFramework.LightProjectDescriptor
+import org.junit.Rule
+import org.junit.rules.ExternalResource
+import org.junit.rules.RuleChain
+import org.junit.rules.TestName
+import org.junit.rules.TestRule
+
+abstract class LightJavaCodeInsightFixtureTestCase4(
+  projectDescriptor: LightProjectDescriptor? = null,
+  protected val testDataPath: String? = null
+) {
+
+  private val testNameRule = TestName()
+
+  protected val testName: String
+    get() {
+      return testNameRule.methodName
+        .split(" ")
+        .joinToString(separator = "") { it.capitalize() }
+        .decapitalize()
+    }
+
+  private val testCase = object : LightJavaCodeInsightFixtureTestCase() {
+
+    override fun getProjectDescriptor(): LightProjectDescriptor = projectDescriptor ?: super.getProjectDescriptor()
+
+    override fun getTestDataPath(): String = this@LightJavaCodeInsightFixtureTestCase4.testDataPath ?: super.getTestDataPath()
+
+    public override fun setUp() = super.setUp()
+
+    public override fun tearDown() = super.tearDown()
+
+    val fixture: JavaCodeInsightTestFixture get() = myFixture
+  }
+
+  private val fixtureRule = object : ExternalResource() {
+
+    override fun before(): Unit = testCase.setUp()
+
+    override fun after(): Unit = testCase.tearDown()
+  }
+
+  protected val fixture: JavaCodeInsightTestFixture get() = testCase.fixture
+
+  @Rule
+  @JvmField
+  val testRule: TestRule = RuleChain.outerRule(testNameRule).around(fixtureRule).around(EdtRule())
+}