Improve user session overview tests

* Add sessions overview UI tests
* Expose static methods from the UserSession name and lastActivity formatters; cleaned up the UserSessionsOverview a bit
* Add UserSessionsOverviewViewModel unit tests
* Add UserSessionsOverviewService unit tests

RiotSwiftUI/Modules/UserSessions/UserSessionsOverview/Test/Unit/UserSessionsOverviewViewModelTests.swift

@@ -20,13 +20,71 @@ import XCTest
 @testable import RiotSwiftUI
 
 class UserSessionsOverviewViewModelTests: XCTestCase {
-    var service: MockUserSessionsOverviewService!
-    var viewModel: UserSessionsOverviewViewModelProtocol!
-    var context: UserSessionsOverviewViewModelType.Context!
+    func testInitialStateEmpty() {
+        let viewModel = UserSessionsOverviewViewModel(userSessionsOverviewService: MockUserSessionsOverviewService())
+        
+        XCTAssertNil(viewModel.state.currentSessionViewData)
+        XCTAssertTrue(viewModel.state.unverifiedSessionsViewData.isEmpty)
+        XCTAssertTrue(viewModel.state.inactiveSessionsViewData.isEmpty)
+        XCTAssertTrue(viewModel.state.otherSessionsViewData.isEmpty)
+    }
     
-    override func setUpWithError() throws {
-        service = MockUserSessionsOverviewService()
-        viewModel = UserSessionsOverviewViewModel(userSessionsOverviewService: service)
-        context = viewModel.context
+    func testLoadOnDidAppear() {
+        let viewModel = UserSessionsOverviewViewModel(userSessionsOverviewService: MockUserSessionsOverviewService())
+        viewModel.process(viewAction: .viewAppeared)
+        
+        XCTAssertNotNil(viewModel.state.currentSessionViewData)
+        XCTAssertFalse(viewModel.state.unverifiedSessionsViewData.isEmpty)
+        XCTAssertFalse(viewModel.state.inactiveSessionsViewData.isEmpty)
+        XCTAssertFalse(viewModel.state.otherSessionsViewData.isEmpty)
+    }
+    
+    func testSimpleActionProcessing() {
+        let viewModel = UserSessionsOverviewViewModel(userSessionsOverviewService: MockUserSessionsOverviewService())
+        
+        var result: UserSessionsOverviewViewModelResult?
+        viewModel.completion = { action in
+            result = action
+        }
+        
+        viewModel.process(viewAction: .verifyCurrentSession)
+        XCTAssertEqual(result, .verifyCurrentSession)
+            
+        viewModel.process(viewAction: .viewAllUnverifiedSessions)
+        XCTAssertEqual(result, .showAllUnverifiedSessions)
+        
+        viewModel.process(viewAction: .viewAllInactiveSessions)
+        XCTAssertEqual(result, .showAllInactiveSessions)
+        
+        viewModel.process(viewAction: .viewAllOtherSessions)
+        XCTAssertEqual(result, .showAllOtherSessions)
+    }
+    
+    func testShowSessionDetails() {
+        let service = MockUserSessionsOverviewService()
+        service.updateOverviewData { _ in }
+        
+        let viewModel = UserSessionsOverviewViewModel(userSessionsOverviewService: service)
+        
+        var result: UserSessionsOverviewViewModelResult?
+        viewModel.completion = { action in
+            result = action
+        }
+        
+        guard let currentSession = service.overviewData.currentSession else {
+            XCTFail("The current session should be valid at this point")
+            return
+        }
+        
+        viewModel.process(viewAction: .viewCurrentSessionDetails)
+        XCTAssertEqual(result, .showCurrentSessionOverview(session: currentSession))
+        
+        guard let randomSession = service.overviewData.otherSessions.randomElement() else {
+            XCTFail("There should be other sessions")
+            return
+        }
+        
+        viewModel.process(viewAction: .tapUserSession(randomSession.id))
+        XCTAssertEqual(result, .showUserSessionOverview(session: randomSession))
     }
 }