void () { myFixture.configureByFile("Lambda.java"); assertEquals(LanguageLevel.JDK_1_6, PsiUtil.getLanguageLevel(myFixture.getFile())); IntentionAction fix = myFixture.findSingleIntention("Set language level"); myFixture.launchAction(fix); assertEquals(LanguageLevel.JDK_1_8, PsiUtil.getLanguageLevel(myFixture.getFile())); }