Added occupancy tests.

Author: maratal

Tests/AblyChatTests/DefaultRoomOccupancyTests.swift

@@ -0,0 +1,75 @@
+import Ably
+@testable import AblyChat
+import Testing
+
+struct DefaultRoomOccupancyTests {
+    // @spec CHA-O3
+    @Test
+    func requestOccupancyCheck() async throws {
+        // Given
+        let realtime = MockRealtime.create {
+            (MockHTTPPaginatedResponse(
+                items: [
+                    [
+                        "connections": 5,
+                        "presenceMembers": 2,
+                    ],
+                ]
+            ), nil)
+        }
+        let chatAPI = ChatAPI(realtime: realtime)
+        let channel = MockRealtimeChannel(name: "basketball::$chat::$chatMessages")
+        let featureChannel = MockFeatureChannel(channel: channel)
+        let defaultOccupancy = DefaultOccupancy(featureChannel: featureChannel, chatAPI: chatAPI, roomID: "basketball", logger: TestLogger())
+
+        // When
+        let occupancyInfo = try await defaultOccupancy.get()
+
+        // Then
+        #expect(occupancyInfo.connections == 5)
+        #expect(occupancyInfo.presenceMembers == 2)
+    }
+
+    // @spec CHA-O4a
+    // @spec CHA-O4c
+    @Test
+    func usersCanSubscribeToRealtimeOccupancyUpdates() async throws {
+        // Given
+        let realtime = MockRealtime.create()
+        let chatAPI = ChatAPI(realtime: realtime)
+        let channel = MockRealtimeChannel(name: "basketball::$chat::$chatMessages")
+        let featureChannel = MockFeatureChannel(channel: channel)
+        let defaultOccupancy = DefaultOccupancy(featureChannel: featureChannel, chatAPI: chatAPI, roomID: "basketball", logger: TestLogger())
+
+        // CHA-O4a, CHA-O4c
+
+        // When
+        let subscription = await defaultOccupancy.subscribe()
+        subscription.emit(OccupancyEvent(connections: 5, presenceMembers: 2))
+
+        // Then
+        let occupancyInfo = try #require(await subscription.first { _ in true })
+        #expect(occupancyInfo.connections == 5)
+        #expect(occupancyInfo.presenceMembers == 2)
+    }
+
+    // @spec CHA-O5
+    @Test
+    func onDiscontinuity() async throws {
+        // Given
+        let realtime = MockRealtime.create()
+        let chatAPI = ChatAPI(realtime: realtime)
+        let channel = MockRealtimeChannel()
+        let featureChannel = MockFeatureChannel(channel: channel)
+        let defaultOccupancy = DefaultOccupancy(featureChannel: featureChannel, chatAPI: chatAPI, roomID: "basketball", logger: TestLogger())
+
+        // When: The feature channel emits a discontinuity through `onDiscontinuity`
+        let featureChannelDiscontinuity = DiscontinuityEvent(error: ARTErrorInfo.createUnknownError()) // arbitrary error
+        let discontinuitySubscription = await defaultOccupancy.onDiscontinuity()
+        await featureChannel.emitDiscontinuity(featureChannelDiscontinuity)
+
+        // Then: The DefaultOccupancy instance emits this discontinuity through `onDiscontinuity`
+        let discontinuity = try #require(await discontinuitySubscription.first { _ in true })
+        #expect(discontinuity == featureChannelDiscontinuity)
+    }
+}