1 /*
2  * Copyright (C) 2011 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 package com.android.tradefed.testtype;
17 
18 import com.android.tradefed.device.ITestDevice;
19 
20 import java.util.Collection;
21 
22 /**
23  * A {@link IRemoteTest} that can be split into separately executable sub-tests. The splitting into
24  * sub-tests is expected to be deterministic and each sub-test should be independent in order to
25  * allow for execution of different shards on different hosts.
26  */
27 public interface IShardableTest extends IRemoteTest {
28 
29     /**
30      * Shard the test into separately runnable chunks.
31      *
32      * <p>This must be deterministic and always return the same list of {@link IRemoteTest}s for the
33      * same input.
34      *
35      * <p>This will be called before test execution, so injected dependencies (such as the {@link
36      * ITestDevice} for {@link IDeviceTest}s) may be null.
37      *
38      * @return a collection of subtests to be executed separately or <code>null</code> if test is
39      *     not currently shardable
40      */
split()41     public default Collection<IRemoteTest> split() {
42         return null;
43     }
44 
45     /**
46      * Alternative version of {@link #split()} which also provides the shardCount that is attempted
47      * to be run. This is useful for some test runner that cannot arbitrarly decide sometimes.
48      *
49      * @param shardCountHint the attempted shard count.
50      * @return a collection of subtests to be executed separately or <code>null</code> if test is
51      *     not currently shardable
52      */
split(int shardCountHint)53     public default Collection<IRemoteTest> split(int shardCountHint) {
54         return split();
55     }
56 }
57