src/test/java/com/android/tools/r8/deadcode/RemoveDeadBuildersTest.java

// Copyright (c) 2019, the R8 project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

package com.android.tools.r8.deadcode;

import static com.android.tools.r8.utils.codeinspector.Matchers.isPresent;
import static org.hamcrest.MatcherAssert.assertThat;
import static org.junit.Assert.assertTrue;

import com.android.tools.r8.TestBase;
import com.android.tools.r8.TestParameters;
import com.android.tools.r8.TestParametersCollection;
import com.android.tools.r8.utils.codeinspector.ClassSubject;
import com.android.tools.r8.utils.codeinspector.CodeInspector;
import com.android.tools.r8.utils.codeinspector.InstructionSubject;
import com.android.tools.r8.utils.codeinspector.MethodSubject;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.Parameterized;
import org.junit.runners.Parameterized.Parameters;

@RunWith(Parameterized.class)
public class RemoveDeadBuildersTest extends TestBase {

  private final TestParameters parameters;

  @Parameters(name = "{0}")
  public static TestParametersCollection data() {
    return getTestParameters().withAllRuntimes().build();
  }

  public RemoveDeadBuildersTest(TestParameters parameters) {
    this.parameters = parameters;
  }

  @Test
  public void test() throws Exception {
    CodeInspector inspector =
        testForR8(parameters.getBackend())
            .addProgramClasses(TestClass.class)
            .addKeepMainRule(TestClass.class)
            .compile()
            .inspector();

    ClassSubject classSubject = inspector.clazz(TestClass.class);
    assertThat(classSubject, isPresent());

    MethodSubject methodSubject = classSubject.mainMethod();
    assertThat(methodSubject, isPresent());
    assertTrue(methodSubject.streamInstructions().noneMatch(InstructionSubject::isNewInstance));
  }

  static class TestClass {

    public static void main(String[] args) {
      new StringBuffer();
      new StringBuffer("Hello world!");
      new StringBuffer((CharSequence) "Hello world!");
      new StringBuffer(42);
      new StringBuilder();
      new StringBuilder("Hello world!");
      new StringBuilder((CharSequence) "Hello world!");
      new StringBuilder(42);
    }
  }
}