Add more onion request tests

SignalServiceKit/src/Loki/API/LokiAPI.swift

@@ -2,7 +2,7 @@ import PromiseKit
 
 @objc(LKAPI)
 public final class LokiAPI : NSObject {
-    private static let stateQueue = DispatchQueue(label: "stateQueue")
+    private static let stateQueue = DispatchQueue(label: "LokiAPI.stateQueue")
 
     /// Only ever modified from the message processing queue (`OWSBatchMessageProcessor.processingQueue`).
     private static var syncMessageTimestamps: [String:Set<UInt64>] = [:]
@@ -22,7 +22,7 @@ public final class LokiAPI : NSObject {
     }
     
     /// All service node related errors must be handled on this queue to avoid race conditions maintaining e.g. failure counts.
-    public static let errorHandlingQueue = DispatchQueue(label: "errorHandlingQueue")
+    public static let errorHandlingQueue = DispatchQueue(label: "LokiAPI.errorHandlingQueue")
     
     // MARK: Convenience
     internal static let storage = OWSPrimaryStorage.shared()

SignalServiceKit/src/Loki/API/Onion Requests/OnionRequestAPI.swift

@@ -123,6 +123,8 @@ internal enum OnionRequestAPI {
     }
 
     /// Returns a `Path` to be used for building an onion request. Builds new paths as needed.
+    ///
+    /// - Note: Exposed for testing purposes.
     internal static func getPath() -> Promise<Path> {
         guard pathSize >= 1 else { preconditionFailure("Cannot build path of size zero.") }
         // randomElement() uses the system's default random generator, which is cryptographically secure

SignalServiceKit/src/Loki/API/Onion Requests/OnionRequestAPITests.swift

@@ -1,13 +1,13 @@
+import PromiseKit
 @testable import SignalServiceKit
 import XCTest
 
 class OnionRequestAPITests : XCTestCase {
-    private let maxRetryCount: UInt = 2 // Be a bit more stringent when testing
 
-    func testGetPath() {
+    func testPathBuilding() {
         let semaphore = DispatchSemaphore(value: 0)
         var error: Error? = nil
-        let _ = OnionRequestAPI.getPath().retryingIfNeeded(maxRetryCount: maxRetryCount).done(on: OnionRequestAPI.workQueue) { _ in
+        let _ = OnionRequestAPI.getPath().done(on: OnionRequestAPI.workQueue) { _ in
             semaphore.signal()
         }.catch(on: OnionRequestAPI.workQueue) {
             error = $0; semaphore.signal()
@@ -16,6 +16,39 @@ class OnionRequestAPITests : XCTestCase {
         XCTAssert(error == nil)
     }
 
-    // TODO: Add request sending test
-    // TODO: Add error handling test
+    /// Builds a path and then routes the same request through it several times. Logs the number of successes
+    /// versus the number of failures.
+    func testOnionRequestSending() {
+        let semaphore = DispatchSemaphore(value: 0)
+        LokiAPI.getRandomSnode().then(on: OnionRequestAPI.workQueue) { snode -> Promise<LokiAPITarget> in
+            return OnionRequestAPI.getPath().map(on: OnionRequestAPI.workQueue) { _ in snode }
+        }.done(on: OnionRequestAPI.workQueue) { snode in
+            var successCount = 0
+            var failureCount = 0
+            let promises: [Promise<Void>] = (0..<16).map { _ in
+                let mockSessionID = "0582bc30f11e8a9736407adcaca03b049f4acd4af3ae7eb6b6608d30f0b1e6a20e"
+                let parameters: JSON = [ "pubKey" : mockSessionID ]
+                let (promise, seal) = Promise<Void>.pending()
+                OnionRequestAPI.invoke(.getSwarm, on: snode, with: parameters).done(on: OnionRequestAPI.workQueue) { _ in
+                    successCount += 1
+                    seal.fulfill(())
+                }.catch(on: OnionRequestAPI.workQueue) { error in
+                    failureCount += 1
+                    seal.reject(error)
+                }.finally(on: OnionRequestAPI.workQueue) {
+                    print("[Loki] [Onion Request API] Success rate: \(successCount)/\(failureCount).")
+                }
+                return promise
+            }
+            when(resolved: promises).done(on: OnionRequestAPI.workQueue) { _ in
+                semaphore.signal()
+            }
+        }.catch(on: OnionRequestAPI.workQueue) { error in
+            print("[Loki] [Onion Request API] Path building failed due to error: \(error).")
+            semaphore.signal()
+        }
+        semaphore.wait()
+    }
+
+    // TODO: Test error handling
 }