1 /*
2  * Copyright 2021 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 androidx.window.testing.layout
18 
19 import android.app.Activity
20 import androidx.window.layout.WindowMetrics
21 import androidx.window.layout.WindowMetricsCalculator
22 import org.junit.rules.TestRule
23 import org.junit.runner.Description
24 import org.junit.runners.model.Statement
25 
26 /**
27  * A [TestRule] that will sub out the actual [WindowMetricsCalculator] with a more simple one that
28  * will support testing independent of the current platform. The fake [WindowMetricsCalculator] that
29  * is used will return the width and height from the [android.util.DisplayMetrics] associated to an
30  * [Activity]. The result of [WindowMetricsCalculator.computeCurrentWindowMetrics] and
31  * [WindowMetricsCalculator.computeMaximumWindowMetrics] will be the same. For accurate results use
32  * the Espresso Test framework with an actual [Activity] and use the actual
33  * [WindowMetricsCalculator].
34  */
35 class WindowMetricsCalculatorRule : TestRule {
36 
37     private val stubWindowMetricsCalculator = StubWindowMetricsCalculator()
38     private val decorator = StubMetricDecorator(stubWindowMetricsCalculator)
39 
applynull40     override fun apply(base: Statement, description: Description): Statement {
41         return object : Statement() {
42             override fun evaluate() {
43                 WindowMetricsCalculator.overrideDecorator(decorator)
44                 try {
45                     base.evaluate()
46                 } finally {
47                     WindowMetricsCalculator.reset()
48                 }
49             }
50         }
51     }
52 
53     /** Overrides the window bounds with a new [WindowMetrics]. */
overrideCurrentWindowBoundsnull54     fun overrideCurrentWindowBounds(windowMetrics: WindowMetrics) {
55         stubWindowMetricsCalculator.overrideWindowBounds(windowMetrics.bounds)
56     }
57 
58     /** Overrides the window bounds with a new rectangle defined by the specified coordinates. */
overrideCurrentWindowBoundsnull59     fun overrideCurrentWindowBounds(left: Int, top: Int, right: Int, bottom: Int) {
60         stubWindowMetricsCalculator.overrideWindowBounds(left, top, right, bottom)
61     }
62 }
63