Define ~= for DispatchQueues, add more DispatchQueue identity tests (Linux)

Author: GarthSnyder

Sources/Configuration.swift

@@ -67,11 +67,11 @@ public struct PMKConfiguration {
         switch dispatcher {
             case nil:
                 return CurrentThreadDispatcher()
-            case DispatchQueue.unspecified:
+            case DispatchQueue.unspecified?:
                 return nil // Do nothing
-            case DispatchQueue.default:
+            case DispatchQueue.default?:
                 return `default`
-            case DispatchQueue.chain:
+            case DispatchQueue.chain?:
                 fatalError("PromiseKit: .chain is not meaningful in the context of setDefaultDispatchers")
             default:
                 return dispatcher!

Sources/Dispatcher.swift

@@ -130,3 +130,9 @@ extension Optional where Wrapped: DispatchQueue {
         return CurrentThreadDispatcher()
     }
 }
+
+extension DispatchQueue {
+    static func ~=(_ a: DispatchQueue, _ b: DispatchQueue) -> Bool {
+        return a === b
+    }
+}

Tests/Core/DispatcherTests.swift

@@ -61,9 +61,14 @@ class DispatcherTests: XCTestCase {
         conf.D = oldConf
     }
 
-    func testPMKDefaultIdentity() {
-        // If this identity does not hold, the DispatchQueue wrapper API will not behave correctly
+    func testDispatchQueueIdentities() {
+        // If these identities does not hold, the DispatchQueue wrapper API will not behave correctly
         XCTAssert(DispatchQueue.unspecified === DispatchQueue.unspecified, "DispatchQueues are not object-identity-preserving on this platform")
+        XCTAssert(DispatchQueue.chain === DispatchQueue.chain, "DispatchQueues are not object-identity-preserving on this platform")
+        XCTAssert(DispatchQueue.default === DispatchQueue.default, "DispatchQueues are not object-identity-preserving on this platform")
+        XCTAssert(DispatchQueue.unspecified !== DispatchQueue.chain, "DispatchQueues are not object-identity-preserving on this platform")
+        XCTAssert(DispatchQueue.chain !== DispatchQueue.default, "DispatchQueues are not object-identity-preserving on this platform")
+        XCTAssert(DispatchQueue.default !== DispatchQueue.unspecified, "DispatchQueues are not object-identity-preserving on this platform")
     }
 
     func testDispatcherWithThrow() {