void () { myFixture.addClass(""" package org.junit.jupiter.api; import org.junit.jupiter.api.function.Executable; public class Assertions { public static void assertAll(String s, Executable... e) {} public static void assertAll(Executable... e) {} public static void assertNotNull(Object o) {} public static void assertTrue(boolean b) {} }"""); myFixture.addClass("package org.junit.jupiter.api.function;public interface Executable { void execute() throws Throwable;}\n"); doTest(); }