Use our own HandlerDispatcher for ComposeUi tests (cashapp#1306)

freeletics · Feb 26, 2024 · 7276226 · 7276226
1 parent 5d158e6
commit 7276226
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Showing 4 changed files with 23 additions and 5 deletions.
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
@@ -3,6 +3,7 @@ agp = "8.2.2"
 androidTools = "31.2.2" # == 23.0.0 + agp version
 bytebuddy = "1.14.12"
 composeCompiler = "1.5.8"
+coroutines = "1.8.0"
 javaTarget = "11"
 jcodec = "0.2.5"
 kotlin = "1.9.22"
@@ -37,7 +38,8 @@ jcodec-core = { module = "org.jcodec:jcodec", version.ref = "jcodec" }
 jcodec-javase = { module = "org.jcodec:jcodec-javase", version.ref = "jcodec" }
 
 kotlin-bom = { module = "org.jetbrains.kotlin:kotlin-bom", version.ref = "kotlin" }
-kotlinx-coroutines-core = { module = "org.jetbrains.kotlinx:kotlinx-coroutines-core", version = "1.8.0" }
+kotlinx-coroutines-core = { module = "org.jetbrains.kotlinx:kotlinx-coroutines-core", version.ref = "coroutines" }
+kotlinx-coroutines-test = { module = "org.jetbrains.kotlinx:kotlinx-coroutines-test", version.ref = "coroutines" }
 
 ksp = { module = "com.google.devtools.ksp:symbol-processing-api", version.ref = "ksp" }
 

diff --git a/paparazzi-gradle-plugin/src/test/projects/coroutine-delay-main/build.gradle b/paparazzi-gradle-plugin/src/test/projects/coroutine-delay-main/build.gradle
@@ -27,6 +27,8 @@ android {
 
 dependencies {
   implementation libs.composeUi.material
+
+  testImplementation libs.kotlinx.coroutines.test
 }
 
 apply from: '../guava-fix.gradle'
diff --git a/...routine-delay-main/src/test/java/app/cash/paparazzi/plugin/test/CoroutineDelayMainTest.kt b/...routine-delay-main/src/test/java/app/cash/paparazzi/plugin/test/CoroutineDelayMainTest.kt
@@ -7,12 +7,21 @@ import app.cash.paparazzi.Paparazzi
 import org.junit.Assert.assertEquals
 import org.junit.Rule
 import org.junit.Test
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.delay
+import kotlinx.coroutines.test.resetMain
 
+@OptIn(ExperimentalCoroutinesApi::class)
 class CoroutineDelayMainTest {
   @get:Rule
   val paparazzi = Paparazzi()
 
+  init {
+    // coroutines-test installs a TestMainDispatcher which is incompatible with ComposeUi
+    Dispatchers.resetMain()
+  }
+
   @Test fun delayUsesMainDispatcher() {
     var start = 0L
     var end = 0L

diff --git a/paparazzi/src/main/java/app/cash/paparazzi/Paparazzi.kt b/paparazzi/src/main/java/app/cash/paparazzi/Paparazzi.kt
@@ -19,6 +19,7 @@ import android.animation.AnimationHandler
 import android.content.Context
 import android.content.res.Resources
 import android.graphics.Bitmap
+import android.os.Handler
 import android.os.Handler_Delegate
 import android.os.SystemClock_Delegate
 import android.util.AttributeSet
@@ -85,7 +86,7 @@ import java.awt.image.BufferedImage
 import java.util.Date
 import java.util.EnumSet
 import java.util.concurrent.TimeUnit
-import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.android.asCoroutineDispatcher
 
 @OptIn(ExperimentalComposeUiApi::class, InternalComposeUiApi::class)
 public class Paparazzi @JvmOverloads constructor(
@@ -303,9 +304,9 @@ public class Paparazzi @JvmOverloads constructor(
 
           // By default, Compose UI uses its own implementation of CoroutineDispatcher, `AndroidUiDispatcher`.
           // Since this dispatcher does not provide its own implementation of Delay, it will default to using DefaultDelay which runs
-          // async to our test Handler. By initializing Recomposer with Dispatchers.Main, Delay will now be backed by our test Handler,
-          // synchronizing expected behavior.
-          WindowRecomposerPolicy.setFactory { it.createLifecycleAwareWindowRecomposer(Dispatchers.Main) }
+          // async to our test Handler. By initializing Recomposer with our own HandlerDispatcher, Delay will now be backed
+          // by our test Handler, synchronizing expected behavior.
+          WindowRecomposerPolicy.setFactory { it.createLifecycleAwareWindowRecomposer(MAIN_DISPATCHER) }
         }
 
         if (hasLifecycleOwnerRuntime) {
@@ -647,6 +648,10 @@ public class Paparazzi @JvmOverloads constructor(
 
     internal lateinit var sessionParamsBuilder: SessionParamsBuilder
 
+    private val MAIN_DISPATCHER by lazy {
+      Handler.getMain().asCoroutineDispatcher("Paparazzi-Main")
+    }
+
     private val isVerifying: Boolean =
       System.getProperty("paparazzi.test.verify")?.toBoolean() == true