// Copyright 2010 The Bazel Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package com.google.testing.junit.runner.sharding;
import org.junit.runner.Description;
import org.junit.runner.manipulation.Filter;
/**
* Sharding filter that uses the hashcode of the test description to
* assign it to a shard.
*/
final class HashBackedShardingFilter extends Filter {
private final int shardIndex;
private final int totalShards;
public HashBackedShardingFilter(int shardIndex, int totalShards) {
if (shardIndex < 0 || totalShards <= shardIndex) {
throw new IllegalArgumentException();
}
this.shardIndex = shardIndex;
this.totalShards = totalShards;
}
@Override
public boolean shouldRun(Description description) {
if (description.isSuite()) {
return true;
}
int mod = description.getDisplayName().hashCode() % totalShards;
if (mod < 0) {
mod += totalShards;
}
if (mod < 0 || mod >= totalShards) {
throw new IllegalStateException();
}
return mod == shardIndex;
}
@Override
public String describe() {
return "hash-backed sharding filter";
}
}