App layout improvements (#10)

This PR contains the work done to improve the app layout for max iPhones and iPads by levering on the navigation split view. Plus, the floating button to add todo tasks was improved and integrated better into the layout and a critical bug occurring on max iPhones and iPads was fixed.

Reviewed-on: rock-n-code/todos-app#10
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

@@ -1,3 +1,4 @@
+import SwiftUI
 import Testing
 
 @testable import Todos
@@ -16,11 +17,37 @@ struct ContentViewModelTests {
 
         // THEN
         #expect(viewModel.newTaskShown == false)
+        #expect(viewModel.group == nil)
+    }
+
+    // MARK: - Computed Property Tests
+
+    @Test(
+        "showNewTaskButtonInDetails returns expected value for every group",
+        arguments: zip(
+            [TodoGroup.today, .upcoming, .overdue, .completed, nil],
+            [true, true, true, false, false]
+        )
+    )
+    func showNewTaskButtonInDetails(
+        for group: TodoGroup?,
+        expects expectation: Bool
+    ) {
+        // GIVEN
+        let viewModel = ContentView.ViewModel()
+
+        viewModel.group = group
+
+        // WHEN
+        let shouldNewTaskButton = viewModel.showNewTaskButtonInDetails
+
+        // THEN
+        #expect(shouldNewTaskButton == expectation)
     }
 
     // MARK: - Functions Tests
 
-    @Test("showNewTask sets showNewTaskView to true")
+    @Test("showNewTask sets newTaskShown to true")
     func newTaskShown() {
         // GIVEN
         let viewModel = ContentView.ViewModel()
@@ -32,4 +59,25 @@ struct ContentViewModelTests {
         #expect(viewModel.newTaskShown == true)
     }
 
+    @Test(
+        "showNewTaskButtonInSidebar returns expected value for every horizontal size class",
+        arguments: zip(
+            [UserInterfaceSizeClass.compact, .regular, nil],
+            [true, false, false]
+        )
+    )
+    func showNewTaskButtonInSidebar(
+        for horizontalSizeClass: UserInterfaceSizeClass?,
+        expects expectation: Bool
+    ) {
+        // GIVEN
+        let viewModel = ContentView.ViewModel()
+
+        // WHEN
+        let shouldNewTaskButton = viewModel.showNewTaskButtonInSidebar(when: horizontalSizeClass)
+
+        // THEN
+        #expect(shouldNewTaskButton == expectation)
+    }
+
 }