1 /*
2  * Copyright (C) 2018 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.car.vehiclehal.test;
17 
18 import android.car.hardware.CarPropertyValue;
19 import android.os.ConditionVariable;
20 
21 import java.util.ArrayList;
22 import java.util.List;
23 
24 /**
25  * The verifier class is used to verify received VHAL events against expected events on-the-fly.
26  * It is initialized with a list of expected events and moving down the list to verify received
27  * events. The verifier object not reusable and should be discarded once the verification is done.
28  * The verifier will provide formatted result for all mismatched events in sequence.
29  */
30 class VhalEventVerifier {
31     private List<CarPropertyValue> mExpectedEvents;
32     // A pointer to keep track of the next expected event in the list
33     private int mIdx;
34     private List<MismatchedEventPair> mMismatchedEvents;
35     // Condition variable to notify waiting threads when verification is done or timeout.
36     private ConditionVariable mCond;
37 
38     static class MismatchedEventPair {
39         public final int idx;
40         public final CarPropertyValue expectedEvent;
41         public final CarPropertyValue mismatchedEvent;
42 
MismatchedEventPair(CarPropertyValue expectedEvent, CarPropertyValue mismatchedEvent, int idx)43         MismatchedEventPair(CarPropertyValue expectedEvent, CarPropertyValue mismatchedEvent,
44                                    int idx) {
45             this.idx = idx;
46             this.expectedEvent = expectedEvent;
47             this.mismatchedEvent = mismatchedEvent;
48         }
49     }
50 
VhalEventVerifier(List<CarPropertyValue> expectedEvents)51     VhalEventVerifier(List<CarPropertyValue> expectedEvents) {
52         mExpectedEvents = expectedEvents;
53         mIdx = 0;
54         mMismatchedEvents = new ArrayList<>();
55         mCond = new ConditionVariable(expectedEvents.isEmpty());
56     }
57 
58     /**
59      * Verification method that checks the equality of received event against expected event. Once
60      * it reaches to the end of list, it will unblock the waiting threads. Note, the verification
61      * method is not thread-safe. It assumes only a single thread is calling the method at all time.
62      *
63      * @param nextEvent to be verified
64      */
verify(CarPropertyValue nextEvent)65     public void verify(CarPropertyValue nextEvent) {
66         if (mIdx >= mExpectedEvents.size()) {
67             return;
68         }
69         CarPropertyValue expectedEvent = mExpectedEvents.get(mIdx);
70         if (!Utils.areCarPropertyValuesEqual(expectedEvent, nextEvent)) {
71             mMismatchedEvents.add(new MismatchedEventPair(expectedEvent, nextEvent, mIdx));
72         }
73         if (++mIdx == mExpectedEvents.size()) {
74             mCond.open();
75         }
76     }
77 
getMismatchedEvents()78     public List<MismatchedEventPair> getMismatchedEvents() {
79         return mMismatchedEvents;
80     }
81 
waitForEnd(long timeout)82     public void waitForEnd(long timeout) {
83         mCond.block(timeout);
84     }
85 
getResultString()86     public String getResultString() {
87         StringBuilder resultBuilder = new StringBuilder();
88         for (MismatchedEventPair pair : mMismatchedEvents) {
89             resultBuilder.append("Index " + pair.idx + ": Expected "
90                     + pair.expectedEvent + ", Received "
91                     + pair.mismatchedEvent + "\n");
92         }
93         return resultBuilder.toString();
94     }
95 }
96