Coroutine tests (#185)

* Add some coroutine tests for implicit cancellation

* Create util test and new helper methods

* Remove coroutinescope extension from withcontext

* Update dependencies

6 files changed, 125 insertions, 31 deletions

diff --git a/buildSrc/src/main/groovy/ca/allanwang/kau/Versions.groovy b/buildSrc/src/main/groovy/ca/allanwang/kau/Versions.groovy
index e6f3cd7..4afec82 100644
--- a/buildSrc/src/main/groovy/ca/allanwang/kau/Versions.groovy
+++ b/buildSrc/src/main/groovy/ca/allanwang/kau/Versions.groovy
@@ -27,7 +27,7 @@ class Versions {
     static def kotlin = '1.3.11'
 
     // https://github.com/Kotlin/kotlinx.coroutines/releases
-    static def coroutines = '1.0.1'
+    static def coroutines = '1.1.0'
 
     // https://github.com/mikepenz/AboutLibraries/releases
     static def aboutLibraries = '6.2.0'
@@ -72,6 +72,8 @@ class Versions {
     static def playPublishPlugin = '1.2.2'
 
     // https://github.com/KeepSafe/dexcount-gradle-plugin/releases
-    static def dexCountPlugin = '0.8.3'
-    static def gitVersionPlugin = '0.4.4'
+    static def dexCountPlugin = '0.8.5'
+
+    // https://github.com/gladed/gradle-android-git-version/releases
+    static def gitVersionPlugin = '0.4.7'
 }
\ No newline at end of file
diff --git a/core/src/main/kotlin/ca/allanwang/kau/utils/ContextUtils.kt b/core/src/main/kotlin/ca/allanwang/kau/utils/ContextUtils.kt
index 09ad4ea..fc8049d 100644
--- a/core/src/main/kotlin/ca/allanwang/kau/utils/ContextUtils.kt
+++ b/core/src/main/kotlin/ca/allanwang/kau/utils/ContextUtils.kt
@@ -26,7 +26,6 @@ import android.content.pm.PackageManager
 import android.graphics.drawable.Drawable
 import android.net.Uri
 import android.os.Bundle
-import android.os.Handler
 import android.os.Looper
 import android.util.TypedValue
 import android.view.View
@@ -47,36 +46,10 @@ import androidx.core.content.ContextCompat
 import ca.allanwang.kau.R
 import ca.allanwang.kau.logging.KL
 import com.afollestad.materialdialogs.MaterialDialog
-import kotlinx.coroutines.CoroutineScope
-import kotlinx.coroutines.android.asCoroutineDispatcher
-import kotlin.coroutines.CoroutineContext
 
 /**
  * Created by Allan Wang on 2017-06-03.
  */
-object ContextHelper : CoroutineScope {
-
-    val looper = Looper.getMainLooper()
-
-    val handler = Handler(looper)
-
-    /**
-     * Creating dispatcher from main handler to avoid IO
-     * See https://github.com/Kotlin/kotlinx.coroutines/issues/878
-     */
-    val dispatcher = handler.asCoroutineDispatcher("kau-main")
-
-    override val coroutineContext: CoroutineContext get() = dispatcher
-}
-
-/**
- * Most context items implement [CoroutineScope] by default.
- * We will add a fallback just in case.
- * It is expected that the scope returned always has the Android main dispatcher as part of the context.
- */
-internal inline val Context.ctxCoroutine: CoroutineScope
-    get() = this as? CoroutineScope ?: ContextHelper
-
 fun Context.runOnUiThread(f: Context.() -> Unit) {
     if (ContextHelper.looper === Looper.myLooper()) f() else ContextHelper.handler.post { f() }
 }
diff --git a/core/src/main/kotlin/ca/allanwang/kau/utils/CoroutineUtils.kt b/core/src/main/kotlin/ca/allanwang/kau/utils/CoroutineUtils.kt
new file mode 100644
index 0000000..032c407
--- /dev/null
+++ b/core/src/main/kotlin/ca/allanwang/kau/utils/CoroutineUtils.kt
@@ -0,0 +1,60 @@
+package ca.allanwang.kau.utils
+
+import android.content.Context
+import android.os.Handler
+import android.os.Looper
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.CoroutineStart
+import kotlinx.coroutines.android.asCoroutineDispatcher
+import kotlinx.coroutines.async
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
+import kotlin.coroutines.CoroutineContext
+import kotlin.coroutines.EmptyCoroutineContext
+
+object ContextHelper : CoroutineScope {
+
+    val looper = Looper.getMainLooper()
+
+    val handler = Handler(looper)
+
+    /**
+     * Creating dispatcher from main handler to avoid IO
+     * See https://github.com/Kotlin/kotlinx.coroutines/issues/878
+     */
+    val dispatcher = handler.asCoroutineDispatcher("kau-main")
+
+    override val coroutineContext: CoroutineContext get() = dispatcher
+}
+
+/**
+ * Most context items implement [CoroutineScope] by default.
+ * We will add a fallback just in case.
+ * It is expected that the scope returned always has the Android main dispatcher as part of the context.
+ */
+internal inline val Context.ctxCoroutine: CoroutineScope
+    get() = this as? CoroutineScope ?: ContextHelper
+
+/**
+ * Calls [launch] with an explicit dispatcher for Android's main thread
+ */
+fun CoroutineScope.launchMain(
+    context: CoroutineContext = EmptyCoroutineContext,
+    start: CoroutineStart = CoroutineStart.DEFAULT,
+    block: suspend CoroutineScope.() -> Unit
+) = launch(ContextHelper.dispatcher + context, start, block)
+
+/**
+ * Calls [async] with an explicit dispatcher for Android's main thread
+ */
+fun CoroutineScope.asyncMain(
+    context: CoroutineContext = EmptyCoroutineContext,
+    start: CoroutineStart = CoroutineStart.DEFAULT,
+    block: suspend CoroutineScope.() -> Unit
+) = async(ContextHelper.dispatcher + context, start, block)
+
+/**
+ * Calls [withContext] with an explicit dispatcher for Android's main thread
+ */
+suspend fun <T> withMainContext(block: suspend CoroutineScope.() -> T) =
+    withContext(ContextHelper.dispatcher, block)
diff --git a/core/src/test/kotlin/ca/allanwang/kau/kotlin/CoroutineTest.kt b/core/src/test/kotlin/ca/allanwang/kau/kotlin/CoroutineTest.kt
new file mode 100644
index 0000000..91d0174
--- /dev/null
+++ b/core/src/test/kotlin/ca/allanwang/kau/kotlin/CoroutineTest.kt
@@ -0,0 +1,58 @@
+package ca.allanwang.kau.kotlin
+
+import kotlinx.coroutines.CancellationException
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.runBlocking
+import kotlinx.coroutines.withContext
+import org.junit.Test
+import kotlin.test.assertEquals
+import kotlin.test.fail
+
+/**
+ * Tests geared towards coroutines
+ */
+class CoroutineTest {
+
+    /**
+     * If a job is cancelled, then a switch to a new context will not run
+     */
+    @Test
+    fun implicitCancellationBefore() {
+        val job = Job()
+        var id = 0
+        try {
+            runBlocking(job) {
+                id++
+                job.cancel()
+                withContext(Dispatchers.IO) {
+                    fail("Context switch should not be reached")
+                }
+            }
+        } catch (ignore: CancellationException) {
+        } finally {
+            assertEquals(1, id, "Launcher never executed")
+        }
+    }
+
+    /**
+     * If a job is cancelled, then a switch from a new context will not run
+     */
+    @Test
+    fun implicitCancellationAfter() {
+        val job = Job()
+        var id = 0
+        try {
+            runBlocking(job) {
+                withContext(Dispatchers.IO) {
+                    id++
+                    job.cancel()
+                }
+                fail("Post context switch should not be reached")
+            }
+        } catch (ignore: CancellationException) {
+        } finally {
+            assertEquals(1, id, "Context switch never executed")
+        }
+    }
+}
\ No newline at end of file
diff --git a/docs/Changelog.md b/docs/Changelog.md
index e6d51d2..7291753 100644
--- a/docs/Changelog.md
+++ b/docs/Changelog.md
@@ -5,6 +5,7 @@
 * :core: Add default CoroutineScope implementation to KauBaseActivity
 * :core: Remove zip class. Coroutines and join can be used as an alternative
 * :core: Delete flyweight implementation. Kotlin already has getOrPut
+* :core: Introduce ContextHelper, where you can get the default looper, handler, and dispatcher for Android
 * :mediapicker: Use video preloading instead of full async loading
 
 ## v4.0.0-alpha01
diff --git a/sample/src/main/res/xml/kau_changelog.xml b/sample/src/main/res/xml/kau_changelog.xml
index 0283d7f..570a0b9 100644
--- a/sample/src/main/res/xml/kau_changelog.xml
+++ b/sample/src/main/res/xml/kau_changelog.xml
@@ -11,10 +11,10 @@
     <item text=":core: Add default CoroutineScope implementation to KauBaseActivity" />
     <item text=":core: Remove zip class. Coroutines and join can be used as an alternative" />
     <item text=":core: Delete flyweight implementation. Kotlin already has getOrPut" />
+    <item text=":core: Introduce ContextHelper, where you can get the default looper, handler, and dispatcher for Android" />
     <item text=":mediapicker: Use video preloading instead of full async loading" />
     <item text="" />
     <item text="" />
-    <item text="" />
 
     <version title="v4.0.0-alpha01" />
     <item text="Migrate to androidx. See migration for external dependency changes." />