void (JavaCodeInsightTestFixture fixture) { fixture.addClass(""" package com.google.common.base; public abstract class Optional<T> { public static <T> Optional<T> absent() { } public static <T> Optional<T> of(@org.jetbrains.annotations.NotNull T reference) { } public static <T> Optional<T> fromNullable(T nullableReference) { } } """); }