Check that FIRAAppCheckDebugToken provided and tests are running

Author: andrewheard

FirebaseVertexAI/Tests/TestApp/Tests/Integration/IntegrationTests.swift

@@ -45,6 +45,13 @@ final class IntegrationTests: XCTestCase {
   var userID1 = ""
 
   override func setUp() async throws {
+    let environment = ProcessInfo.processInfo.environment
+    if environment["FIRAAppCheckDebugToken"] == nil {
+      XCTFail("No App Check debug token provided in FIRAAppCheckDebugToken.")
+    } else {
+      XCTFail("App Check debug token provided; failing to check that tests are running.")
+    }
+
     let authResult = try await Auth.auth().signIn(
       withEmail: Credentials.emailAddress1,
       password: Credentials.emailPassword1