Refactor AbstractHighLevelMultiFileJvmBasicCompletionTest

Use `KotlinFixtureCompletionBaseTestCase` base because it can override
`getProjectDescriptor`, so the tests will see full JDK

Without it, there were problems when classes from JDK appeared in the
completion (`Serialization`, for example)

idea/idea-completion/testData/basic/multifile/ExtensionsForSmartCast/ExtensionsForSmartCast.kt

@@ -1,3 +1,4 @@
+// FIR_COMPARISON
 val String.extensionProp1: Int get() = 1
 val String.extensionProp2: Int get() = 1
 

idea/idea-completion/testData/basic/multifile/FileRefInStringLiteralNoPrefix/FileRefInStringLiteralNoPrefix.kt

@@ -1,4 +1,3 @@
-// FIR_COMPARISON
 // NUMBER: 3
 // EXIST: foo.txt
 // EXIST: bar.txt

idea/idea-completion/testData/basic/multifile/NoGenericFunDuplication/NoGenericFunDuplication.kt

@@ -1,3 +1,4 @@
+// FIR_COMPARISON
 // this test tests correct substitution equality checking for generic functions
 import java.io.InputStreamReader
 

idea/idea-completion/testData/basic/multifile/NotImportedExtensionForImplicitReceiver/NotImportedExtensionForImplicitReceiver.kt

@@ -1,3 +1,4 @@
+// FIR_COMPARISON
 package first
 
 class C {

idea/idea-completion/testData/basic/multifile/NotImportedExtensionFunction/NotImportedExtensionFunction.kt

@@ -1,3 +1,4 @@
+// FIR_COMPARISON
 package first
 
 fun firstFun() {

idea/idea-fir/tests/org/jetbrains/kotlin/idea/completion/AbstractHighLevelMultiFileJvmBasicCompletionTest.kt

@@ -6,26 +6,34 @@
 package org.jetbrains.kotlin.idea.completion
 
 import com.intellij.codeInsight.completion.CompletionType
-import org.jetbrains.kotlin.idea.completion.test.AbstractMultiFileJvmBasicCompletionTest
-import org.jetbrains.kotlin.idea.completion.test.testCompletion
+import com.intellij.testFramework.LightProjectDescriptor
+import org.jetbrains.kotlin.idea.completion.test.KotlinFixtureCompletionBaseTestCase
+import org.jetbrains.kotlin.platform.TargetPlatform
 import org.jetbrains.kotlin.platform.jvm.JvmPlatforms
 import org.jetbrains.kotlin.test.uitls.IgnoreTests
-import java.nio.file.Path
 import java.nio.file.Paths
+import org.jetbrains.kotlin.idea.test.KotlinWithJdkAndRuntimeLightProjectDescriptor
 
-abstract class AbstractHighLevelMultiFileJvmBasicCompletionTest : AbstractMultiFileJvmBasicCompletionTest() {
-    private val testDataFile: Path
-        get() = Paths.get(testDataPath, getTestName(false) + ".kt")
+abstract class AbstractHighLevelMultiFileJvmBasicCompletionTest : KotlinFixtureCompletionBaseTestCase() {
+    override val captureExceptions: Boolean = false
 
-    override fun doTest(testPath: String) {
-        IgnoreTests.runTestIfEnabledByFileDirective(testDataFile, IgnoreTests.DIRECTIVES.FIR_COMPARISON) {
-            configureByFile(getTestName(false) + ".kt", "")
-
-            testCompletion(file.text, JvmPlatforms.unspecifiedJvmPlatform, { completionType, invocationCount ->
-                setType(completionType)
-                complete(invocationCount)
-                myItems
-            }, CompletionType.BASIC, 0)
+    override fun executeTest(test: () -> Unit) {
+        IgnoreTests.runTestIfEnabledByFileDirective(testDataFile().toPath(), IgnoreTests.DIRECTIVES.FIR_COMPARISON) {
+            test()
         }
     }
+
+    override fun getTestDataPath(): String = Paths.get(super.getTestDataPath(), getTestName(false)).toString()
+
+    override fun fileName(): String = getTestName(false) + ".kt"
+
+    override fun setUpFixture(testPath: String) {
+        // We need to copy all files from the testDataPath (= "") to the tested project
+        myFixture.copyDirectoryToProject("", "")
+        super.setUpFixture(testPath)
+    }
+
+    override fun defaultCompletionType(): CompletionType = CompletionType.BASIC
+    override fun getPlatform(): TargetPlatform = JvmPlatforms.unspecifiedJvmPlatform
+    override fun getProjectDescriptor(): LightProjectDescriptor = KotlinWithJdkAndRuntimeLightProjectDescriptor.INSTANCE
 }