src/test/java/com/android/tools/r8/shaking/UsageInformationConsumerTest.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.shaking;

import static org.junit.Assert.assertEquals;

import com.android.tools.r8.DiagnosticsHandler;
import com.android.tools.r8.StringConsumer;
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 java.io.ByteArrayOutputStream;
import java.io.PrintStream;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.Parameterized;

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

  static final String EXPECTED = StringUtils.lines("Hello, world");

  private final TestParameters parameters;

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

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

  public static class UsageConsumer implements StringConsumer {
    String data = null;

    @Override
    public void accept(String string, DiagnosticsHandler handler) {
      data = string;
    }
  };

  @Test
  public void testConsumer() throws Exception {
    UsageConsumer usageConsumer = new UsageConsumer();
    testForR8(parameters.getBackend())
        .addProgramClasses(TestClass.class, UnusedClass.class)
        .addKeepClassAndMembersRules(TestClass.class)
        .apply(b -> b.getBuilder().setProguardUsageConsumer(usageConsumer))
        .setMinApi(parameters.getApiLevel())
        .run(parameters.getRuntime(), TestClass.class)
        .assertSuccessWithOutput(EXPECTED);
    assertEquals(StringUtils.lines(UnusedClass.class.getTypeName()), usageConsumer.data);
  }

  @Test
  public void testRule() throws Exception {
    ByteArrayOutputStream out = new ByteArrayOutputStream();
    testForR8(parameters.getBackend())
        .redirectStdOut(new PrintStream(out))
        .addProgramClasses(TestClass.class, UnusedClass.class)
        .addKeepClassAndMembersRules(TestClass.class)
        .addKeepRules("-printusage")
        .setMinApi(parameters.getApiLevel())
        .run(parameters.getRuntime(), TestClass.class)
        .assertSuccessWithOutput(EXPECTED);
    assertEquals(StringUtils.lines(UnusedClass.class.getTypeName()), out.toString());
  }

  static class UnusedClass {
    public static void foo() {
      System.out.println("FOO!");
    }
  }

  static class TestClass {
    public static void main(String[] args) {
      System.out.println("Hello, world");
    }
  }
}