Add test for message provider

src/test/kotlin/test/initialcapacity/streaming/messages/MessageProviderTest.kt

@@ -0,0 +1,17 @@
+package test.initialcapacity.streaming.messages
+
+import io.initialcapacity.streaming.messages.MessageProvider
+import kotlinx.coroutines.runBlocking
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.time.Duration
+
+class MessageProviderTest {
+    @Test
+    fun testFetchAll() = runBlocking {
+        assertEquals(
+            listOf("Here's some slow content.", "It took a while to load.", "And didn't use any javascript."),
+            MessageProvider(Duration.ZERO).fetchAll()
+        )
+    }
+}