New task feature (#2)

This PR contains the work done to implement the **New Task** feature, and to integrate it into the main context view of the app.

Reviewed-on: rock-n-code/todos-app#2
Co-authored-by: Javier Cicchelli <javier@rock-n-code.com>
Co-committed-by: Javier Cicchelli <javier@rock-n-code.com>

UnitTests/Tests/View Models/ContentViewModelTests.swift

@@ -0,0 +1,36 @@
+import Foundation
+import SwiftData
+import Testing
+
+@testable import Todos
+
+@Suite("ContentView.ViewModel Tests")
+struct ContentViewModelTests {
+
+    // MARK: Initialization Tests
+
+    @Test("View model initializes with default values")
+    func initialization() {
+        // GIVEN
+        // WHEN
+        let viewModel = ContentView.ViewModel()
+
+        // THEN
+        #expect(viewModel.newTaskShown == false)
+    }
+
+    // MARK: - Functions Tests
+
+    @Test("showNewTask sets showNewTaskView to true")
+    func newTaskShown() {
+        // GIVEN
+        let viewModel = ContentView.ViewModel()
+
+        // WHEN
+        viewModel.showNewTask()
+
+        // THEN
+        #expect(viewModel.newTaskShown == true)
+    }
+
+}