From b9cf4129fcd061cfda56fa4aa644c05f952f9220 Mon Sep 17 00:00:00 2001
From: Tlaster <tlaster@outlook.com>
Date: Mon, 26 Jun 2023 13:25:40 +0800
Subject: [PATCH] add BackDispatcherTest

---
 buildSrc/src/main/kotlin/Versions.kt          |  2 +-
 precompose/build.gradle.kts                   |  1 +
 .../tlaster/precompose/ui/BackPressAdapter.kt |  3 +-
 .../navigation/BackDispatcherTest.kt          | 47 +++++++++++++++++++
 4 files changed, 51 insertions(+), 2 deletions(-)
 create mode 100644 precompose/src/commonTest/kotlin/moe/tlaster/precompose/navigation/BackDispatcherTest.kt

diff --git a/buildSrc/src/main/kotlin/Versions.kt b/buildSrc/src/main/kotlin/Versions.kt
index c6d7f311..837bcc6d 100644
--- a/buildSrc/src/main/kotlin/Versions.kt
+++ b/buildSrc/src/main/kotlin/Versions.kt
@@ -11,7 +11,7 @@ object Versions {
 
     object Kotlin {
         const val lang = "1.8.20"
-        const val coroutines = "1.6.4"
+        const val coroutines = "1.7.1"
     }
 
     object Java {
diff --git a/precompose/build.gradle.kts b/precompose/build.gradle.kts
index 65729c5d..4fe81294 100644
--- a/precompose/build.gradle.kts
+++ b/precompose/build.gradle.kts
@@ -49,6 +49,7 @@ kotlin {
                 api(compose.animation)
                 implementation(kotlin("test-common"))
                 implementation(kotlin("test-annotations-common"))
+                implementation("org.jetbrains.kotlinx:kotlinx-coroutines-test:${Versions.Kotlin.coroutines}")
                 // @OptIn(org.jetbrains.compose.ExperimentalComposeLibrary::class)
                 // implementation(compose.uiTestJUnit4)
             }
diff --git a/precompose/src/commonMain/kotlin/moe/tlaster/precompose/ui/BackPressAdapter.kt b/precompose/src/commonMain/kotlin/moe/tlaster/precompose/ui/BackPressAdapter.kt
index d3173f27..fcf9a750 100644
--- a/precompose/src/commonMain/kotlin/moe/tlaster/precompose/ui/BackPressAdapter.kt
+++ b/precompose/src/commonMain/kotlin/moe/tlaster/precompose/ui/BackPressAdapter.kt
@@ -12,7 +12,8 @@ interface BackDispatcherOwner {
 }
 
 class BackDispatcher {
-    private val handlers = arrayListOf<BackHandler>()
+    // internal for testing
+    internal val handlers = arrayListOf<BackHandler>()
 
     fun onBackPress() {
         handlers.lastOrNull {
diff --git a/precompose/src/commonTest/kotlin/moe/tlaster/precompose/navigation/BackDispatcherTest.kt b/precompose/src/commonTest/kotlin/moe/tlaster/precompose/navigation/BackDispatcherTest.kt
new file mode 100644
index 00000000..bbadb426
--- /dev/null
+++ b/precompose/src/commonTest/kotlin/moe/tlaster/precompose/navigation/BackDispatcherTest.kt
@@ -0,0 +1,47 @@
+package moe.tlaster.precompose.navigation
+
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.test.runTest
+import moe.tlaster.precompose.ui.BackDispatcher
+import moe.tlaster.precompose.ui.BackHandler
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class BackDispatcherTest {
+
+    @Test
+    fun onBackPress_should_call_handleBackPress_on_the_last_enabled_handler() {
+        val dispatcher = BackDispatcher()
+        val handler1 = object : BackHandler {
+            override val isEnabled = true
+            override fun handleBackPress() {}
+        }
+        val handler2 = object : BackHandler {
+            override val isEnabled = true
+            override fun handleBackPress() {}
+        }
+        dispatcher.register(handler1)
+        dispatcher.register(handler2)
+
+        dispatcher.onBackPress()
+
+        assertEquals(handler2, dispatcher.handlers.last())
+    }
+
+    @Test
+    fun canHandleBackPress_should_return_true_if_any_handler_is_enabled() = runTest {
+        val dispatcher = BackDispatcher()
+        val handler1 = object : BackHandler {
+            override val isEnabled = true
+            override fun handleBackPress() {}
+        }
+        val handler2 = object : BackHandler {
+            override val isEnabled = true
+            override fun handleBackPress() {}
+        }
+        dispatcher.register(handler1)
+        dispatcher.register(handler2)
+
+        assertEquals(true, dispatcher.canHandleBackPress.first())
+    }
+}