src/test/java/com/android/tools/r8/classmerging/horizontalstatic/StaticClassMergerTest.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.horizontalstatic;

import static org.junit.Assert.assertEquals;

import com.android.tools.r8.CompilationFailedException;
import com.android.tools.r8.NeverInline;
import com.android.tools.r8.TestBase;
import com.android.tools.r8.TestParameters;
import com.android.tools.r8.TestParametersCollection;
import com.android.tools.r8.utils.StringUtils;
import com.android.tools.r8.utils.codeinspector.FoundClassSubject;
import java.io.IOException;
import java.util.List;
import java.util.concurrent.ExecutionException;
import java.util.stream.Collectors;
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 StaticClassMergerTest extends TestBase {

  static class StaticMergeCandidateA {

    @NeverInline
    public static void m() {
      System.out.println("StaticMergeCandidateA.m()");
    }
  }

  static class StaticMergeCandidateB {

    @NeverInline
    public static void m() {
      System.out.println("StaticMergeCandidateB.m()");
    }
  }

  static class TestClass {

    public static void main(String[] args) {
      StaticMergeCandidateA.m();
      StaticMergeCandidateB.m();
    }
  }

  private final String EXPECTED =
      StringUtils.lines("StaticMergeCandidateA.m()", "StaticMergeCandidateB.m()");

  private final TestParameters parameters;

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

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

  @Test
  public void testRuntime() throws IOException, CompilationFailedException, ExecutionException {
    testForRuntime(parameters.getRuntime(), parameters.getApiLevel())
        .addInnerClasses(StaticClassMergerTest.class)
        .run(parameters.getRuntime(), TestClass.class)
        .assertSuccessWithOutput(EXPECTED);
  }

  @Test
  public void testStaticClassIsRemoved() throws Exception {
    testForR8(parameters.getBackend())
        .addInnerClasses(getClass())
        .addKeepMainRule(TestClass.class)
        .addHorizontallyMergedClassesInspector(
            inspector ->
                inspector.assertMergedInto(
                    StaticMergeCandidateB.class, StaticMergeCandidateA.class))
        .enableInliningAnnotations()
        .setMinApi(parameters.getApiLevel())
        .run(parameters.getRuntime(), TestClass.class)
        .assertSuccessWithOutput(EXPECTED)
        .inspect(
            inspector -> {
              // Check that one of the two static merge candidates has been removed
              List<FoundClassSubject> classes =
                  inspector.allClasses().stream()
                      .filter(clazz -> clazz.getOriginalName().contains("StaticMergeCandidate"))
                      .collect(Collectors.toList());
              assertEquals(1, classes.size());

              // Check that the remaining static merge candidate has two methods.
              FoundClassSubject remaining = classes.get(0);
              assertEquals(2, remaining.allMethods().size());
            });
  }
}