com.google.devtools.build.android.desugar.DesugarObjectsRequireNonNullTest.java Source code

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Here is the source code for com.google.devtools.build.android.desugar.DesugarObjectsRequireNonNullTest.java

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// Copyright 2016 The Bazel Authors. All rights reserved.
//
// 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.devtools.build.android.desugar;

import static com.google.common.truth.Truth.assertThat;
import static org.junit.Assert.fail;
import static org.objectweb.asm.Opcodes.INVOKESTATIC;

import com.google.devtools.build.android.desugar.testdata.ClassCallingRequireNonNull;
import java.io.IOException;
import java.util.concurrent.atomic.AtomicInteger;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;
import org.objectweb.asm.ClassReader;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;

/**
 * This test case tests the desugaring feature for Objects.requireNonNull. This feature replaces any
 * call to this method with o.getClass() to check whether 'o' is null.
 */
@RunWith(JUnit4.class)
public class DesugarObjectsRequireNonNullTest {

    @Test
    public void testClassCallingRequireNonNullHasNoReferenceToRequiresNonNull() {
        try {
            ClassReader reader = new ClassReader(ClassCallingRequireNonNull.class.getName());

            AtomicInteger counterForSingleArgument = new AtomicInteger(0);
            AtomicInteger counterForString = new AtomicInteger(0);
            AtomicInteger counterForSupplier = new AtomicInteger(0);

            reader.accept(new ClassVisitor(Opcodes.ASM5) {
                @Override
                public MethodVisitor visitMethod(int access, String name, String desc, String signature,
                        String[] exceptions) {
                    return new MethodVisitor(api) {
                        @Override
                        public void visitMethodInsn(int opcode, String owner, String name, String desc,
                                boolean itf) {
                            if (opcode == INVOKESTATIC && owner.equals("java/util/Objects")
                                    && name.equals("requireNonNull")) {
                                switch (desc) {
                                case "(Ljava/lang/Object;)Ljava/lang/Object;":
                                    counterForSingleArgument.incrementAndGet();
                                    break;
                                case "(Ljava/lang/Object;Ljava/lang/String;)Ljava/lang/Object;":
                                    counterForString.incrementAndGet();
                                    break;
                                case "(Ljava/lang/Object;Ljava/util/function/Supplier;)Ljava/lang/Object;":
                                    counterForSupplier.incrementAndGet();
                                    break;
                                default:
                                    fail("Unknown overloaded requireNonNull is found: " + desc);
                                }
                            }
                        }
                    };
                }
            }, 0);
            assertThat(counterForSingleArgument.get()).isEqualTo(0);
            // we do not desugar requireNonNull(Object, String) or requireNonNull(Object, Supplier)
            assertThat(counterForString.get()).isEqualTo(1);
            assertThat(counterForSupplier.get()).isEqualTo(1);
        } catch (IOException e) {
            fail();
        }
    }

    @Test
    public void testInliningImplicitCallToObjectsRequireNonNull() {
        try {
            ClassCallingRequireNonNull.getStringLengthWithMethodReference(null);
            fail("NullPointerException expected");
        } catch (NullPointerException e) {
            // Expected
        }

        assertThat(ClassCallingRequireNonNull.getStringLengthWithMethodReference("")).isEqualTo(0);
        assertThat(ClassCallingRequireNonNull.getStringLengthWithMethodReference("1")).isEqualTo(1);

        try {
            ClassCallingRequireNonNull.getStringLengthWithLambdaAndExplicitCallToRequireNonNull(null);
            fail("NullPointerException expected");
        } catch (NullPointerException e) {
            // Expected
        }

        assertThat(ClassCallingRequireNonNull.getStringLengthWithLambdaAndExplicitCallToRequireNonNull(""))
                .isEqualTo(0);
        assertThat(ClassCallingRequireNonNull.getStringLengthWithLambdaAndExplicitCallToRequireNonNull("1"))
                .isEqualTo(1);
    }

    @Test
    public void testInliningExplicitCallToObjectsRequireNonNull() {
        try {
            ClassCallingRequireNonNull.getFirstCharVersionOne(null);
            fail("NullPointerException expected");
        } catch (NullPointerException e) {
            // Expected
        }

        try {
            ClassCallingRequireNonNull.getFirstCharVersionTwo(null);
            fail("NullPointerException expected");
        } catch (NullPointerException e) {
            // Expected
        }

        try {
            ClassCallingRequireNonNull.callRequireNonNullWithArgumentString(null);
            fail("NullPointerException expected");
        } catch (NullPointerException e) {
            // Expected
        }

        try {
            ClassCallingRequireNonNull.callRequireNonNullWithArgumentSupplier(null);
            fail("NullPointerException expected");
        } catch (NullPointerException e) {
            // Expected
        }

        assertThat(ClassCallingRequireNonNull.getFirstCharVersionOne("hello")).isEqualTo('h');
        assertThat(ClassCallingRequireNonNull.getFirstCharVersionTwo("hello")).isEqualTo('h');

        assertThat(ClassCallingRequireNonNull.callRequireNonNullWithArgumentString("hello")).isEqualTo('h');
        assertThat(ClassCallingRequireNonNull.callRequireNonNullWithArgumentSupplier("hello")).isEqualTo('h');
    }
}