1 files changed, 110 insertions, 0 deletions
diff --git a/app/src/test/kotlin/com/pitchedapps/frost/views/FrostContentViewAsyncTest.kt b/app/src/test/kotlin/com/pitchedapps/frost/views/FrostContentViewAsyncTest.kt
new file mode 100644
index 00000000..a179fb98
--- /dev/null
+++ b/app/src/test/kotlin/com/pitchedapps/frost/views/FrostContentViewAsyncTest.kt
@@ -0,0 +1,110 @@
+package com.pitchedapps.frost.views
+
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.ExecutorCoroutineDispatcher
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.asCoroutineDispatcher
+import kotlinx.coroutines.async
+import kotlinx.coroutines.channels.BroadcastChannel
+import kotlinx.coroutines.channels.ReceiveChannel
+import kotlinx.coroutines.runBlocking
+import kotlinx.coroutines.withContext
+import java.util.concurrent.Executors
+import kotlin.test.AfterTest
+import kotlin.test.BeforeTest
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+/**
+ * Collection of tests around the view thread logic
+ */
+@UseExperimental(ExperimentalCoroutinesApi::class)
+class FrostContentViewAsyncTest {
+
+    /**
+     * Single threaded dispatcher with thread name "main"
+     * Mimics the usage of Android's main dispatcher
+     */
+    private lateinit var mainDispatcher: ExecutorCoroutineDispatcher
+
+    @BeforeTest
+    fun before() {
+        mainDispatcher = Executors.newSingleThreadExecutor { r ->
+            Thread(r, "main")
+        }.asCoroutineDispatcher()
+    }
+
+    @AfterTest
+    fun after() {
+        mainDispatcher.close()
+    }
+
+    /**
+     * Hooks onto the refresh channel for one true -> false cycle.
+     * Returns the list of event ids that were emitted
+     */
+    private suspend fun transition(channel: ReceiveChannel<Pair<Boolean, Int>>): List<Pair<Boolean, Int>> {
+        var refreshed = false
+        return listen(channel) { (refreshing, _) ->
+            if (refreshed && !refreshing)
+                return@listen true
+            if (refreshing)
+                refreshed = true
+            return@listen false
+        }
+    }
+
+    private suspend fun <T> listen(channel: ReceiveChannel<T>, shouldEnd: (T) -> Boolean = { false }): List<T> =
+        withContext(Dispatchers.IO) {
+            val data = mutableListOf<T>()
+            for (c in channel) {
+                data.add(c)
+                if (shouldEnd(c)) break
+            }
+            channel.cancel()
+            return@withContext data
+        }
+
+    /**
+     * When refreshing, we have a temporary subscriber that hooks onto a single cycle.
+     * The refresh channel only contains booleans, but for the sake of identification,
+     * each boolean will have a unique integer attached.
+     *
+     * Things to note:
+     * Subscription should be opened outside of async, since we don't want to miss any events.
+     */
+    @Test
+    fun refreshSubscriptions() {
+        val refreshChannel = BroadcastChannel<Pair<Boolean, Int>>(100)
+        runBlocking {
+            // Listen to all events
+            val fullReceiver = refreshChannel.openSubscription()
+            val fullDeferred = async { listen(fullReceiver) }
+
+            refreshChannel.send(true to 1)
+            refreshChannel.send(false to 2)
+            refreshChannel.send(true to 3)
+
+            val partialReceiver = refreshChannel.openSubscription()
+            val partialDeferred = async { transition(partialReceiver) }
+            refreshChannel.send(false to 4)
+            refreshChannel.send(true to 5)
+            refreshChannel.send(false to 6)
+            refreshChannel.send(true to 7)
+            refreshChannel.close()
+            val fullStream = fullDeferred.await()
+            val partialStream = partialDeferred.await()
+
+            assertEquals(
+                7,
+                fullStream.size,
+                "Full stream should contain all events"
+            )
+            assertEquals(
+                listOf(false to 4, true to 5, false to 6),
+                partialStream,
+                "Partial stream should include up until first true false pair"
+            )
+        }
+    }
+}
+\ No newline at end of file