[Sessions] Use Notifications for Initiator tests (#10576)

Author: samedson

FirebaseSessions/Sources/SessionInitiator.swift

@@ -89,11 +89,11 @@ class SessionInitiator {
     #endif
   }
 
-  @objc func appBackgrounded() {
+  @objc private func appBackgrounded() {
     backgroundTime = currentTime()
   }
 
-  @objc func appForegrounded() {
+  @objc private func appForegrounded() {
     let interval = currentTime().timeIntervalSince(backgroundTime)
     if interval > sessionTimeout {
       initiateSessionStart()

FirebaseSessions/Tests/Unit/InitiatorTests.swift

@@ -15,17 +15,58 @@
 import XCTest
 @testable import FirebaseSessions
 
+#if os(iOS) || os(tvOS)
+  import UIKit
+#elseif os(macOS)
+  import Cocoa
+  import AppKit
+#elseif os(watchOS)
+  import WatchKit
+#endif
+
 class InitiatorTests: XCTestCase {
   // 2021-11-01 @ 00:00:00 (EST)
   let date = Date(timeIntervalSince1970: 1_635_739_200)
 
+  func postBackgroundedNotification() {
+    let notificationCenter = NotificationCenter.default
+    #if os(iOS) || os(tvOS)
+      notificationCenter.post(name: UIApplication.didEnterBackgroundNotification, object: nil)
+    #elseif os(macOS)
+      notificationCenter.post(name: NSApplication.didResignActiveNotification, object: nil)
+    #elseif os(watchOS)
+      if #available(watchOSApplicationExtension 7.0, *) {
+        notificationCenter.post(
+          name: WKExtension.applicationDidEnterBackgroundNotification,
+          object: nil
+        )
+      }
+    #endif
+  }
+
+  func postForegroundedNotification() {
+    let notificationCenter = NotificationCenter.default
+    #if os(iOS) || os(tvOS)
+      notificationCenter.post(name: UIApplication.didBecomeActiveNotification, object: nil)
+    #elseif os(macOS)
+      notificationCenter.post(name: NSApplication.didBecomeActiveNotification, object: nil)
+    #elseif os(watchOS)
+      if #available(watchOSApplicationExtension 7.0, *) {
+        notificationCenter.post(
+          name: WKExtension.applicationDidBecomeActiveNotification,
+          object: nil
+        )
+      }
+    #endif
+  }
+
   func test_beginListening_initiatesColdStart() throws {
     let initiator = SessionInitiator()
     var initiateCalled = false
     initiator.beginListening {
       initiateCalled = true
     }
-    assert(initiateCalled)
+    XCTAssert(initiateCalled)
   }
 
   func test_appForegrounded_initiatesNewSession() throws {
@@ -36,24 +77,24 @@ class InitiatorTests: XCTestCase {
     initiator.beginListening {
       sessionCount += 1
     }
-    assert(sessionCount == 1)
+    XCTAssert(sessionCount == 1)
 
     // When
     // Background, advance time by 30 minutes + 1 second, then foreground
-    initiator.appBackgrounded()
+    postBackgroundedNotification()
     pausedClock.addTimeInterval(30 * 60 + 1)
-    initiator.appForegrounded()
+    postForegroundedNotification()
     // Then
     // Session count increases because time spent in background > 30 minutes
-    assert(sessionCount == 2)
+    XCTAssert(sessionCount == 2)
 
     // When
     // Background, advance time by exactly 30 minutes, then foreground
-    initiator.appBackgrounded()
+    postBackgroundedNotification()
     pausedClock.addTimeInterval(30 * 60)
-    initiator.appForegrounded()
+    postForegroundedNotification()
     // Then
     // Session count doesn't increase because time spent in background <= 30 minutes
-    assert(sessionCount == 2)
+    XCTAssert(sessionCount == 2)
   }
 }