Add PromiseKit dependency

- Added PromiseKit dependency

Carthage/Checkouts/PromiseKit/Extensions/MessagesUI/Tests/TestMessageUI.swift

@@ -0,0 +1,69 @@
+import PMKMessagesUI
+import PromiseKit
+import MessageUI
+import XCTest
+import UIKit
+
+
+class MessageUITests: XCTestCase {
+    var rootvc: UIViewController!
+
+    func test_can_cancel_mail_composer() {
+        let ex1 = expectation(description: "")
+        let ex2 = expectation(description: "")
+        var order = false
+
+        let mailer = MFMailComposeViewController()
+        mailer.setToRecipients(["mxcl@me.com"])
+
+        let promise = rootvc.promise(mailer, animated: false, completion: {
+            after(seconds: 0.25).done { _ in
+                XCTAssertFalse(order)
+                let button = mailer.viewControllers[0].navigationItem.leftBarButtonItem!
+                UIControl().sendAction(button.action!, to: button.target, for: nil)
+                ex1.fulfill()
+            }
+        })
+        promise.catch { _ -> Void in
+            XCTFail()
+        }
+        promise.catch(policy: .allErrors) { _ -> Void in
+            // seems necessary to give vc stack a bit of time
+            after(seconds: 0.5).done(ex2.fulfill)
+            order = true
+        }
+        waitForExpectations(timeout: 10, handler: nil)
+
+        XCTAssertNil(rootvc.presentedViewController)
+    }
+
+    func test_can_cancel_message_composer() {
+        let ex1 = expectation(description: "")
+        let ex2 = expectation(description: "")
+        var order = false
+
+        let messager = MFMessageComposeViewController()
+
+        let promise = rootvc.promise(messager, animated: false, completion: {
+            after(seconds: 0.25).done { _ in
+                XCTAssertFalse(order)
+
+                let button = messager.viewControllers[0].navigationItem.leftBarButtonItem!
+                UIControl().sendAction(button.action!, to: button.target, for: nil)
+                ex1.fulfill()
+            }
+        })
+
+        promise.catch { _ -> Void in
+            XCTFail()
+        }
+        promise.catch(policy: .allErrors) { _ -> Void in
+            // seems necessary to give vc stack a bit of time
+            after(seconds: 0.5).done(ex2.fulfill)
+            order = true
+        }
+        waitForExpectations(timeout: 10, handler: nil)
+
+        XCTAssertNil(rootvc.presentedViewController)
+    }
+}