1 /*
2  * Copyright (C) 2023 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 
17 package com.android.systemui.util.test
18 
19 import android.util.Log
20 
21 /**
22  * Helper class that intercepts test errors which may be occurring on the wrong thread, and saves
23  * them so that they can be rethrown back on the correct thread.
24  */
25 class TestExceptionDeferrer(private val tag: String, private val testThread: Thread) {
26     private val deferredErrors = mutableListOf<IllegalStateException>()
27 
28     /** Ensure the [value] is `true`; otherwise [fail] with the produced [message] */
29     fun check(value: Boolean, message: () -> Any?) {
30         if (value) return
31         fail(message().toString())
32     }
33 
34     /**
35      * If the [Thread.currentThread] is the [testThread], then [error], otherwise [Log] and defer
36      * the error until [throwDeferred] is called.
37      */
38     fun fail(message: String) {
39         if (testThread == Thread.currentThread()) {
40             error(message)
41         } else {
42             val exception = IllegalStateException(message)
43             Log.e(tag, "Deferring error: ", exception)
44             deferredErrors.add(exception)
45         }
46     }
47 
48     /** If any [fail] or failed [check] has happened, throw the first one. */
49     fun throwDeferred() {
50         deferredErrors.firstOrNull()?.let { firstError ->
51             Log.e(tag, "Deferred errors: ${deferredErrors.size}")
52             deferredErrors.clear()
53             throw firstError
54         }
55     }
56 }
57