src/test/java/com/android/tools/r8/classmerging/horizontal/EmptyClassTest.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.classmerging.horizontal;

import static com.android.tools.r8.utils.codeinspector.Matchers.isPresent;
import static org.hamcrest.MatcherAssert.assertThat;
import static org.hamcrest.core.IsNot.not;

import com.android.tools.r8.NeverClassInline;
import com.android.tools.r8.TestParameters;
import org.junit.Test;

public class EmptyClassTest extends HorizontalClassMergingTestBase {
  public EmptyClassTest(TestParameters parameters, boolean enableHorizontalClassMerging) {
    super(parameters, enableHorizontalClassMerging);
  }

  @Test
  public void testR8() throws Exception {
    testForR8(parameters.getBackend())
        .addInnerClasses(getClass())
        .addKeepMainRule(Main.class)
        .addOptionsModification(
            options -> options.enableHorizontalClassMerging = enableHorizontalClassMerging)
        .enableNeverClassInliningAnnotations()
        .setMinApi(parameters.getApiLevel())
        .run(parameters.getRuntime(), Main.class)
        .assertSuccess()
        .inspect(
            codeInspector -> {
              if (enableHorizontalClassMerging) {
                assertThat(codeInspector.clazz(A.class), isPresent());
                assertThat(codeInspector.clazz(B.class), not(isPresent()));
                // TODO(b/165517236): Explicitly check classes have been merged.
              } else {
                assertThat(codeInspector.clazz(A.class), isPresent());
                assertThat(codeInspector.clazz(B.class), isPresent());
              }
            });
  }

  @NeverClassInline
  public static class A {}

  @NeverClassInline
  public static class B {
    // TODO(b/164924717): remove non overlapping constructor requirement
    public B(String s) {}
  }

  public static class Main {
    public static void main(String[] args) {
      A a = new A();
      System.out.println(a);
      B b = new B("");
      System.out.println(b);
    }
  }
}