void () { myFixture.addClass(""" package org.junit.jupiter.api; import java.util.function.Supplier; public final class Assertions { public static native <T> T assertInstanceOf(Class<T> expectedType, Object actualValue); public static <T> T assertInstanceOf(Class<T> expectedType, Object actualValue, String message); public static <T> T assertInstanceOf(Class<T> expectedType, Object actualValue, Supplier<String> messageSupplier); } """); checkHighlighting(); }