1 /*
2  * Copyright (C) 2020 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.server.testutils
18 
19 import org.mockito.Answers
20 import org.mockito.ArgumentMatchers
21 import org.mockito.Mockito
22 import org.mockito.invocation.InvocationOnMock
23 import org.mockito.stubbing.Answer
24 import org.mockito.stubbing.Stubber
25 
26 object MockitoUtils {
27     val ANSWER_THROWS = Answer<Any?> {
28         when (val name = it.method.name) {
29             "toString" -> return@Answer try {
30                 Answers.CALLS_REAL_METHODS.answer(it)
31             } catch (e: Exception) {
32                 "failure calling toString"
33             }
34             else -> {
35                 val arguments = it.arguments
36                         ?.takeUnless { it.isEmpty() }
37                         ?.mapIndexed { index, arg -> arg.attemptToString(index) }
38                         ?.joinToString { it.attemptToString(null) }
39                         ?.let { "with $it" }
40                         .orEmpty()
41 
42                 throw UnsupportedOperationException("${it.mock::class.java.simpleName}#$name " +
43                         "$arguments should not be called")
44             }
45         }
46     }
47 
48     // Sometimes mocks won't have a toString method, so try-catch and return some default
49     private fun Any?.attemptToString(id: Any? = null): String {
50         return try {
51             toString()
52         } catch (e: Exception) {
53             if (id == null) {
54                 e.message ?: "ERROR"
55             } else {
56                 "$id ${e.message}"
57             }
58         }
59     }
60 }
61 
62 inline fun <reified T> mock(block: T.() -> Unit = {}) = Mockito.mock(T::class.java).apply(block)
63 
64 fun <T> spy(value: T, block: T.() -> Unit = {}) = Mockito.spy(value).apply(block)
65 
66 fun <Type> Stubber.whenever(mock: Type) = this.`when`(mock)
67 fun <Type : Any?> whenever(mock: Type) = Mockito.`when`(mock)
68 
69 @Suppress("UNCHECKED_CAST")
70 fun <Type> whenever(mock: Type, block: InvocationOnMock.() -> Type) =
71         Mockito.`when`(mock).thenAnswer { block(it) }
72 
73 fun whenever(mock: Unit) = Mockito.`when`(mock).thenAnswer { }
74 
75 inline fun <reified T> spyThrowOnUnmocked(value: T?, block: T.() -> Unit = {}): T {
76     val swappingAnswer = object : Answer<Any?> {
77         var delegate: Answer<*> = Answers.RETURNS_DEFAULTS
78 
79         override fun answer(invocation: InvocationOnMock?): Any? {
80             return delegate.answer(invocation)
81         }
82     }
83 
84     return Mockito.mock(T::class.java, Mockito.withSettings().spiedInstance(value)
85             .defaultAnswer(swappingAnswer)).apply(block)
86             .also {
87                 // To allow when() usage inside block, only swap to throwing afterwards
88                 swappingAnswer.delegate = MockitoUtils.ANSWER_THROWS
89             }
90 }
91 
92 inline fun <reified T> mockThrowOnUnmocked(block: T.() -> Unit = {}) =
93         spyThrowOnUnmocked<T>(null, block)
94 
95 inline fun <reified T : Any> nullable() = ArgumentMatchers.nullable(T::class.java)
96 
97 /**
98  * Returns Mockito.any() as nullable type to avoid java.lang.IllegalStateException when
99  * null is returned.
100  *
101  * Generic T is nullable because implicitly bounded by Any?.
102  */
103 fun <T> any(type: Class<T>): T = Mockito.any<T>(type)
104 
105 /**
106  * Wrapper around [Mockito.any] for generic types.
107  */
108 inline fun <reified T> any() = any(T::class.java)
109 
110 /**
111  * Returns Mockito.eq() as nullable type to avoid java.lang.IllegalStateException when
112  * null is returned.
113  *
114  * Generic T is nullable because implicitly bounded by Any?.
115  */
116 fun <T> eq(obj: T): T = Mockito.eq<T>(obj)
117