Add MemoryManagement tests confirming view controllers don't have retain cycles

- Created verifyObjectsDeallocatedAfterTeardown method that can be used for confirming that any object is deallocated after it's lifecycle should end
- Testing most of the view controllers confirming that there aren't easily reproducible memory leaks remaining

Author: staskus

WordPressAuthenticator.xcodeproj/project.pbxproj

@@ -7,6 +7,7 @@
 	objects = {
 
 /* Begin PBXBuildFile section */
+		0193F7752A615521004D7C16 /* MemoryManagementTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 0193F7742A615521004D7C16 /* MemoryManagementTests.swift */; };
 		020BE74A23B0BD2E007FE54C /* WordPressAuthenticatorDisplayImages.swift in Sources */ = {isa = PBXBuildFile; fileRef = 020BE74923B0BD2E007FE54C /* WordPressAuthenticatorDisplayImages.swift */; };
 		020DEF6428AA091100C85D51 /* MagicLinkRequester.swift in Sources */ = {isa = PBXBuildFile; fileRef = 020DEF6328AA091100C85D51 /* MagicLinkRequester.swift */; };
 		02A526CA28A3499C00FD1812 /* MagicLinkRequestedViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 02A526C828A3499C00FD1812 /* MagicLinkRequestedViewController.swift */; };
@@ -261,6 +262,7 @@
 /* End PBXCopyFilesBuildPhase section */
 
 /* Begin PBXFileReference section */
+		0193F7742A615521004D7C16 /* MemoryManagementTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MemoryManagementTests.swift; sourceTree = "<group>"; };
 		020BE74923B0BD2E007FE54C /* WordPressAuthenticatorDisplayImages.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = WordPressAuthenticatorDisplayImages.swift; sourceTree = "<group>"; };
 		020DEF6328AA091100C85D51 /* MagicLinkRequester.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MagicLinkRequester.swift; sourceTree = "<group>"; };
 		02A526C828A3499C00FD1812 /* MagicLinkRequestedViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MagicLinkRequestedViewController.swift; sourceTree = "<group>"; };
@@ -956,6 +958,7 @@
 				3F86A83F29D280DC005D20C0 /* SingIn */,
 				F18DF0E32525009200D83AFE /* SupportingFiles */,
 				3F338B6B289B87E60014ADC5 /* UnitTests.xctestplan */,
+				0193F7742A615521004D7C16 /* MemoryManagementTests.swift */,
 			);
 			path = WordPressAuthenticatorTests;
 			sourceTree = "<group>";
@@ -1552,6 +1555,7 @@
 			buildActionMask = 2147483647;
 			files = (
 				3F4E64782990BBD4000DB555 /* IDTokenTests.swift in Sources */,
+				0193F7752A615521004D7C16 /* MemoryManagementTests.swift in Sources */,
 				3F86A84E29D3B53D005D20C0 /* SocialServiceTests.swift in Sources */,
 				3F879FDB293A49AA005C2B48 /* NewGoogleAuthenticatorTests.swift in Sources */,
 				F18DF0E5252500A600D83AFE /* WordPressAuthenticatorTests-Bridging-Header.h in Sources */,

WordPressAuthenticatorTests/MemoryManagementTests.swift

@@ -0,0 +1,60 @@
+@testable import WordPressAuthenticator
+import XCTest
+
+final class MemoryManagementTests: XCTestCase {
+    override func setUp() {
+        super.setUp()
+
+        WordPressAuthenticator.initialize(
+          configuration: WordpressAuthenticatorProvider.wordPressAuthenticatorConfiguration(),
+          style: WordpressAuthenticatorProvider.wordPressAuthenticatorStyle(.random),
+          unifiedStyle: WordpressAuthenticatorProvider.wordPressAuthenticatorUnifiedStyle(.random)
+        )
+    }
+
+    func testViewControllersDeallocatedAfterDismissing() {
+        let viewControllers: [UIViewController] = [
+            Storyboard.login.instance.instantiateInitialViewController()!,
+            LoginPrologueLoginMethodViewController.instantiate(from: .login)!,
+            LoginPrologueSignupMethodViewController.instantiate(from: .login)!,
+            Login2FAViewController.instantiate(from: .login)!,
+            LoginEmailViewController.instantiate(from: .login)!,
+            LoginSelfHostedViewController.instantiate(from: .login)!,
+            LoginSiteAddressViewController.instantiate(from: .login)!,
+            LoginUsernamePasswordViewController.instantiate(from: .login)!,
+            LoginWPComViewController.instantiate(from: .login)!,
+            SignupEmailViewController.instantiate(from: .signup)!,
+            SignupGoogleViewController.instantiate(from: .signup)!,
+            GetStartedViewController.instantiate(from: .getStarted)!,
+            VerifyEmailViewController.instantiate(from: .verifyEmail)!,
+            PasswordViewController.instantiate(from: .password)!,
+            TwoFAViewController.instantiate(from: .twoFA)!,
+            GoogleAuthViewController.instantiate(from: .googleAuth)!,
+            SiteAddressViewController.instantiate(from: .siteAddress)!,
+            SiteCredentialsViewController.instantiate(from: .siteAddress)!
+        ]
+
+        for viewController in viewControllers {
+            viewController.loadViewIfNeeded()
+        }
+
+        verifyObjectsDeallocatedAfterTeardown(viewControllers)
+    }
+
+    // MARK: - Helpers
+
+    private func verifyObjectsDeallocatedAfterTeardown(_ objects: [AnyObject]) {
+        /// Create the array of weak objects so we could assert them in the teardown block
+        let weakObjects: [() -> AnyObject?] = objects.map { object in { [weak object] in
+                return object
+            }
+        }
+
+        /// All the weak items should be deallocated in the teardown block unless there's a retain cycle holding them
+        addTeardownBlock {
+            for object in weakObjects {
+                XCTAssertNil(object(), "\(object()!.self) is not deallocated after teardown")
+            }
+        }
+    }
+}