Configure sdk properly in configure Kotlin tests

idea/idea-test-framework/src/org/jetbrains/kotlin/idea/test/PluginTestCaseBase.java

@@ -16,9 +16,13 @@
 
 package org.jetbrains.kotlin.idea.test;
 
+import com.intellij.openapi.Disposable;
+import com.intellij.openapi.application.ApplicationManager;
 import com.intellij.openapi.projectRoots.JavaSdk;
+import com.intellij.openapi.projectRoots.ProjectJdkTable;
 import com.intellij.openapi.projectRoots.Sdk;
 import com.intellij.openapi.projectRoots.impl.JavaSdkImpl;
+import com.intellij.openapi.util.Disposer;
 import com.intellij.openapi.util.text.StringUtil;
 import com.intellij.openapi.vfs.newvfs.impl.VfsRootAccess;
 import org.jetbrains.annotations.NotNull;
@@ -56,6 +60,17 @@ public class PluginTestCaseBase {
         return getSdk("compiler/testData/mockJDK/jre", "Mock JDK");
     }
 
+    @NotNull
+    public static Sdk mockJdk6() {
+        return getSdk("compiler/testData/mockJDK/jre", "1.6");
+    }
+
+    @NotNull
+    public static Sdk mockJdk8() {
+        // Using JDK 6, but with version 1.8
+        return getSdk("compiler/testData/mockJDK/jre", "1.8");
+    }
+
     @TestOnly
     @NotNull
     public static Sdk mockJdk9() {
@@ -89,4 +104,14 @@ public class PluginTestCaseBase {
     public static boolean isAllFilesPresentTest(@NotNull String testName) {
         return StringUtil.startsWithIgnoreCase(testName, "allFilesPresentIn");
     }
+
+    @TestOnly
+    public static void clearSdkTable(@NotNull Disposable disposable) {
+        Disposer.register(disposable, () -> ApplicationManager.getApplication().runWriteAction(() -> {
+            ProjectJdkTable jdkTable = ProjectJdkTable.getInstance();
+            for (Sdk sdk : jdkTable.getAllJdks()) {
+                jdkTable.removeJdk(sdk);
+            }
+        }));
+    }
 }