Create unit tests for supported extensions and update readme

Author: Damir Tursunović

README.md

@@ -170,8 +170,12 @@ class SceneDelegate: UIResponder, UIWindowSceneDelegate {
 }
 ```
 
+
 If you incorporate background-uploading, we strongly recommend you to inspect any failed uploads that may have occured in the background. Please refer to [Starting a new Session](#Starting a new Session) for more information.
 
+## TUS Protocol Extensions
+The client assumes by default that the server implements the [Creation TUS protocol extension](https://tus.io/protocols/resumable-upload.html#protocol-extensions). If your server does not support that, please ensure to provide an empty array for the `supportedExtensions` parameter in the client initializer.
+
 ## Example app
 
 Please refer to the [example app](/TUSKitExample) inside this project to see how to add photos from a PHPicker, using SwiftUI. You can also use the `PHPicker` mechanic for UIKit.

Sources/TUSKit/TUSClient.swift

@@ -90,6 +90,10 @@ public final class TUSClient {
     ///   You can also pass an absolute path, e.g. "file://uploads/TUS"
     ///   - session: A URLSession you'd like to use. Will default to `URLSession.shared`.
     ///   - chunkSize: The amount of bytes the data to upload will be chunked by. Defaults to 512 kB.
+    ///   - supportedExtensions: The TUS protocol extensions that the client should use. For now, the available supported extensions are `.creation`. Defaults to `[.creation]`.
+    ///
+    /// - Important: The client assumes by default that your server implements the Creation TUS protocol extension. If your server does not support that,
+    ///   make sure that you provide an empty array in the `supportExtensions` parameter.
     /// - Throws: File related errors when it can't make a directory at the designated path.
     public init(server: URL, sessionIdentifier: String, storageDirectory: URL? = nil, session: URLSession = URLSession.shared, chunkSize: Int = 500 * 1024, supportedExtensions: [TUSProtocolExtension] = [.creation]) throws {
         self.sessionIdentifier = sessionIdentifier

Sources/TUSKit/TUSProtocolExtension.swift

@@ -5,11 +5,8 @@
 //  Created by Brad Patras on 7/14/22.
 //
 
+/// Available [TUS protocol extensions](https://tus.io/protocols/resumable-upload.html#protocol-extensions) that
+/// the client supports.
 public enum TUSProtocolExtension {
     case creation
 }
-
-extension Array where Element == TUSProtocolExtension {
-    public static let all: [TUSProtocolExtension] = [.creation]
-}
-

Tests/TUSKitTests/Support/Support.swift

@@ -30,14 +30,18 @@ func clearDirectory(dir: URL) {
     }
 }
 
-func makeClient(storagePath: URL?) -> TUSClient {
+func makeClient(storagePath: URL?, supportedExtensions: [TUSProtocolExtension] = [.creation]) -> TUSClient {
     let liveDemoPath = URL(string: "https://tusd.tusdemo.net/files")!
 
     // We don't use a live URLSession, we mock it out.
     let configuration = URLSessionConfiguration.default
     configuration.protocolClasses = [MockURLProtocol.self]
     do {
-        let client = try TUSClient(server: liveDemoPath, sessionIdentifier: "TEST", storageDirectory: storagePath, session: URLSession.init(configuration: configuration))
+        let client = try TUSClient(server: liveDemoPath,
+                                   sessionIdentifier: "TEST",
+                                   storageDirectory: storagePath,
+                                   session: URLSession.init(configuration: configuration),
+                                   supportedExtensions: supportedExtensions)
         return client
     } catch {
         XCTFail("Could not create TUSClient instance \(error)")

Tests/TUSKitTests/TUSClient/TUSClientTests.swift

@@ -90,6 +90,42 @@ final class TUSClientTests: XCTestCase {
         XCTAssertEqual(0, client.remainingUploads)
     }
 
+    // MARK: - Supported Extensions
+    
+    func testClientExcludesCreationStep() throws {
+        prepareNetworkForSuccesfulStatusCall(data: data)
+        client = makeClient(storagePath: fullStoragePath, supportedExtensions: [])
+        client.delegate = tusDelegate
+        
+        // Act
+        try client.upload(data: data)
+        waitForUploadsToFinish()
+        
+        // Assert (ensure that the create HTTP request has not been called)
+        XCTAssertFalse(MockURLProtocol.receivedRequests.contains(where: {
+            $0.httpMethod == "POST" &&
+            $0.url?.absoluteString == "https://tusd.tusdemo.net/files" &&
+            $0.allHTTPHeaderFields?["Upload-Extension"] == "creation"
+        }))
+    }
+    
+    func testClientIncludesCreationStep() throws {
+        prepareNetworkForSuccesfulStatusCall(data: data)
+        client = makeClient(storagePath: fullStoragePath, supportedExtensions: [.creation])
+        client.delegate = tusDelegate
+        
+        // Act
+        try client.upload(data: data)
+        waitForUploadsToFinish()
+        
+        // Assert (ensure that the create HTTP request has not been called)
+        XCTAssert(MockURLProtocol.receivedRequests.contains(where: {
+            $0.httpMethod == "POST" &&
+            $0.url?.absoluteString == "https://tusd.tusdemo.net/files" &&
+            $0.allHTTPHeaderFields?["Upload-Extension"] == "creation"
+        }))
+    }
+    
     /// Upload data, a certain amount of times, and wait for it to be done.
     /// Can optionally prepare a failing upload too.
     @discardableResult