src/test/java/com/android/tools/r8/ir/optimize/string/UnusedStringBuilderWithAppendObjectSideEffectTest.java

// Copyright (c) 2020, 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.ir.optimize.string;

import static com.android.tools.r8.utils.codeinspector.CodeMatchers.instantiatesClass;
import static org.hamcrest.CoreMatchers.not;
import static org.hamcrest.MatcherAssert.assertThat;

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.MethodSubject;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.Parameterized;

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

  private final TestParameters parameters;

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

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

  @Test
  public void test() throws Exception {
    testForR8(parameters.getBackend())
        .addInnerClasses(getClass())
        .addKeepMainRule(Main.class)
        .setMinApi(parameters.getApiLevel())
        .compile()
        .inspect(
            inspector -> {
              MethodSubject mainMethod = inspector.clazz(Main.class).mainMethod();
              assertThat(mainMethod, not(instantiatesClass(StringBuilder.class)));
            })
        .run(parameters.getRuntime(), Main.class)
        .assertSuccessWithOutputLines("A");
  }

  static class Main {

    public static void main(String[] args) {
      new StringBuilder().append(new A()).toString();
    }
  }

  static class A {

    @Override
    public String toString() {
      System.out.println("A");
      return "A";
    }
  }
}