add files for create room screen, add selected users section with test

UnitTests/Sources/CreateRoomViewModelTests.swift

@@ -0,0 +1,43 @@
+//
+// Copyright 2022 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import XCTest
+
+@testable import ElementX
+
+@MainActor
+class CreateRoomScreenViewModelTests: XCTestCase {
+    var viewModel: CreateRoomViewModelProtocol!
+    var clientProxy: MockClientProxy!
+    
+    var context: CreateRoomViewModel.Context {
+        viewModel.context
+    }
+    
+    override func setUpWithError() throws {
+        clientProxy = .init(userID: "")
+        let viewModel = CreateRoomViewModel(selectedUsers: [.mockAlice, .mockBob, .mockCharlie])
+        self.viewModel = viewModel
+    }
+    
+    func testDeselectUser() {
+        XCTAssertFalse(context.viewState.selectedUsers.isEmpty)
+        XCTAssertEqual(context.viewState.selectedUsers.count, 3)
+        XCTAssertEqual(context.viewState.selectedUsers.first?.userID, UserProfile.mockAlice.userID)
+        context.send(viewAction: .deselectUser(.mockAlice))
+        XCTAssertNotEqual(context.viewState.selectedUsers.first?.userID, UserProfile.mockAlice.userID)
+    }
+}