| /* |
| * Copyright (C) 2016 The Guava Authors |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package com.google.common.reflect; |
| |
| import static com.google.common.base.Preconditions.checkState; |
| import static com.google.common.truth.Truth.assertThat; |
| |
| import com.google.errorprone.annotations.RequiredModifiers; |
| import java.lang.annotation.ElementType; |
| import java.lang.annotation.Retention; |
| import java.lang.annotation.RetentionPolicy; |
| import java.lang.annotation.Target; |
| import java.lang.reflect.Method; |
| import java.lang.reflect.Type; |
| import java.util.Arrays; |
| import java.util.Comparator; |
| import javax.lang.model.element.Modifier; |
| |
| /** |
| * Tester of subtyping relationships between two types. |
| * |
| * <p>Tests should inherit from this class, and declare subtyping relationship with public methods |
| * annotated by {@link TestSubtype}. |
| * |
| * <p>These declaration methods rely on Java static type checking to make sure what we want to |
| * assert as subtypes are really subtypes according to javac. For example: |
| * |
| * <pre>{@code |
| * class MySubtypeTests extends SubtypeTester { |
| * @TestSubtype(suppressGetSubtype = true, suppressGetSupertype = true) |
| * public <T> Iterable<? extends T> listIsSubtypeOfIterable(List<T> list) { |
| * return isSubtype(list); |
| * } |
| * |
| * @TestSubtype |
| * public List<String> intListIsNotSubtypeOfStringList(List<Integer> intList) { |
| * return notSubtype(intList); |
| * } |
| * } |
| * |
| * public void testMySubtypes() throws Exception { |
| * new MySubtypeTests().testAllDeclarations(); |
| * } |
| * }</pre> |
| * |
| * The calls to {@link #isSubtype} and {@link #notSubtype} tells the framework what assertions need |
| * to be made. |
| * |
| * <p>The declaration methods must be public. |
| */ |
| @AndroidIncompatible // only used by android incompatible tests. |
| abstract class SubtypeTester implements Cloneable { |
| |
| /** Annotates a public method that declares subtype assertion. */ |
| @RequiredModifiers(Modifier.PUBLIC) |
| @Retention(RetentionPolicy.RUNTIME) |
| @Target(ElementType.METHOD) |
| @interface TestSubtype { |
| /** Suppresses the assertion on {@link TypeToken#getSubtype}. */ |
| boolean suppressGetSubtype() default false; |
| |
| /** Suppresses the assertion on {@link TypeToken#getSupertype}. */ |
| boolean suppressGetSupertype() default false; |
| } |
| |
| private Method method = null; |
| |
| /** Call this in a {@link TestSubtype} public method asserting subtype relationship. */ |
| final <T> T isSubtype(T sub) { |
| Type returnType = method.getGenericReturnType(); |
| Type paramType = getOnlyParameterType(); |
| TestSubtype spec = method.getAnnotation(TestSubtype.class); |
| assertThat(TypeToken.of(paramType).isSubtypeOf(returnType)) |
| .named("%s is subtype of %s", paramType, returnType) |
| .isTrue(); |
| assertThat(TypeToken.of(returnType).isSupertypeOf(paramType)) |
| .named("%s is supertype of %s", returnType, paramType) |
| .isTrue(); |
| if (!spec.suppressGetSubtype()) { |
| assertThat(getSubtype(returnType, TypeToken.of(paramType).getRawType())).isEqualTo(paramType); |
| } |
| if (!spec.suppressGetSupertype()) { |
| assertThat(getSupertype(paramType, TypeToken.of(returnType).getRawType())) |
| .isEqualTo(returnType); |
| } |
| return sub; |
| } |
| |
| /** |
| * Call this in a {@link TestSubtype} public method asserting that subtype relationship does not |
| * hold. |
| */ |
| final <X> X notSubtype(@SuppressWarnings("unused") Object sub) { |
| Type returnType = method.getGenericReturnType(); |
| Type paramType = getOnlyParameterType(); |
| TestSubtype spec = method.getAnnotation(TestSubtype.class); |
| assertThat(TypeToken.of(paramType).isSubtypeOf(returnType)) |
| .named("%s is subtype of %s", paramType, returnType) |
| .isFalse(); |
| assertThat(TypeToken.of(returnType).isSupertypeOf(paramType)) |
| .named("%s is supertype of %s", returnType, paramType) |
| .isFalse(); |
| if (!spec.suppressGetSubtype()) { |
| try { |
| assertThat(getSubtype(returnType, TypeToken.of(paramType).getRawType())) |
| .isNotEqualTo(paramType); |
| } catch (IllegalArgumentException notSubtype1) { |
| // The raw class isn't even a subclass. |
| } |
| } |
| if (!spec.suppressGetSupertype()) { |
| try { |
| assertThat(getSupertype(paramType, TypeToken.of(returnType).getRawType())) |
| .isNotEqualTo(returnType); |
| } catch (IllegalArgumentException notSubtype2) { |
| // The raw class isn't even a subclass. |
| } |
| } |
| return null; |
| } |
| |
| final void testAllDeclarations() throws Exception { |
| checkState(method == null); |
| Method[] methods = getClass().getMethods(); |
| Arrays.sort( |
| methods, |
| new Comparator<Method>() { |
| @Override |
| public int compare(Method a, Method b) { |
| return a.getName().compareTo(b.getName()); |
| } |
| }); |
| for (Method method : methods) { |
| if (method.isAnnotationPresent(TestSubtype.class)) { |
| method.setAccessible(true); |
| SubtypeTester tester = (SubtypeTester) clone(); |
| tester.method = method; |
| method.invoke(tester, new Object[] {null}); |
| } |
| } |
| } |
| |
| private Type getOnlyParameterType() { |
| assertThat(method.getGenericParameterTypes()).hasLength(1); |
| return method.getGenericParameterTypes()[0]; |
| } |
| |
| @SuppressWarnings({"rawtypes", "unchecked"}) |
| private static Type getSupertype(Type type, Class<?> superclass) { |
| Class rawType = superclass; |
| return TypeToken.of(type).getSupertype(rawType).getType(); |
| } |
| |
| private static Type getSubtype(Type type, Class<?> subclass) { |
| return TypeToken.of(type).getSubtype(subclass).getType(); |
| } |
| } |