Group tasks feature (#3)

This PR contains the work done to implement the **Group Task** feature, and to integrate it into the main content view of the app. Furthermore, an issue related to triggering a view update after inserting the todo tasks into the model container has been fixed.

Reviewed-on: rock-n-code/todos-app#3
Co-authored-by: Javier Cicchelli <javier@rock-n-code.com>
Co-committed-by: Javier Cicchelli <javier@rock-n-code.com>

UnitTests/Tests/Enumerations/TodoGroupTests.swift

@@ -0,0 +1,99 @@
+import Foundation
+import SwiftUI
+import Testing
+
+@testable import Todos
+
+@Suite("TodoGroup enumeration tests")
+struct TodoGroupTests {
+
+    // MARK: Computed tests
+
+    @Test(
+        "group color match expected values",
+        arguments: zip(
+            TodoGroup.allCases,
+            [Color.blue, .green, .red, .gray]
+        )
+    )
+    func color(
+        for group: TodoGroup,
+        expects expectation: Color
+    ) {
+        // GIVEN
+        // WHEN
+        let color = group.color
+
+        // THEN
+        #expect(color == expectation)
+    }
+
+    @Test(
+        "group icon names match expected values",
+        arguments: zip(
+            TodoGroup.allCases,
+            ["calendar.badge.clock", "calendar", "calendar.badge.exclamationmark", "checkmark.circle.fill"]
+        )
+    )
+    func iconName(
+        for group: TodoGroup,
+        expects expectation: String
+    ) {
+        // GIVEN
+        // WHEN
+        let iconName = group.iconName
+
+        // THEN
+        #expect(iconName == expectation)
+    }
+
+    @Test(
+        "group titles match expected values",
+        arguments: zip(
+            TodoGroup.allCases,
+            ["today", "upcoming", "overdue", "completed"]
+        )
+    )
+    func title(
+        for group: TodoGroup,
+        expects expectation: String
+    ) {
+        // GIVEN
+        let key = "enumeration.todo-group.title." + expectation
+
+        // WHEN
+        let title = group.title
+
+        // THEN
+        #expect(title == .init(key))
+    }
+
+    // MARK: Case Iteration Tests
+
+    @Test("all cases contains all cases, in correct order")
+    func allCases() {
+        // GIVEN
+        // WHEN
+        let allCases = TodoGroup.allCases
+
+        // THEN
+        #expect(allCases.count == 4)
+        #expect(allCases[0] == .today)
+        #expect(allCases[1] == .upcoming)
+        #expect(allCases[2] == .overdue)
+        #expect(allCases[3] == .completed)
+    }
+
+    // MARK: Identifiable Tests
+
+    @Test("id returns an identity of a case", arguments: TodoGroup.allCases)
+    func id(for group: TodoGroup) {
+        // GIVEN
+        // WHEN
+        let id = group.id
+
+        // THEN
+        #expect(id == group)
+    }
+
+}

UnitTests/Tests/View Models/ContentViewModelTests.swift

@@ -4,7 +4,7 @@ import Testing
 
 @testable import Todos
 
-@Suite("ContentView.ViewModel Tests")
+@Suite("ContentView view model tests")
 struct ContentViewModelTests {
 
     // MARK: Initialization Tests

UnitTests/Tests/View Models/NewTaskViewModelTests.swift

@@ -4,7 +4,7 @@ import Testing
 
 @testable import Todos
 
-@Suite("NewTaskView ViewModel Tests")
+@Suite("NewTaskView view model tests")
 struct NewTaskViewModelTests {
 
     // MARK: Initialization tests

UnitTests/Tests/View Models/TaskGroupListViewModelTests.swift

@@ -0,0 +1,82 @@
+import Foundation
+import SwiftData
+import Testing
+
+@testable import Todos
+
+@Suite("TaskGroupListView view model tests")
+struct TaskGroupListViewModelTests {
+
+    // MARK: Properties
+
+    private let calendar: Calendar = .current
+
+    // MARK: Computed tests
+
+    @Test("groups returns cases in predetermined order")
+    func groups() {
+        // GIVEN
+        let viewModel = TaskGroupListView.ViewModel()
+
+        // WHEN
+        let groups = viewModel.groups
+
+        // THEN
+        #expect(groups.count == 4)
+        #expect(groups[0] == .today)
+        #expect(groups[1] == .upcoming)
+        #expect(groups[2] == .overdue)
+        #expect(groups[3] == .completed)
+    }
+
+    // MARK: Functions tests
+
+    @Test(
+        "count returns zero when empty data",
+        arguments: TodoGroup.allCases
+    )
+    func countWhenEmptyData(for group: TodoGroup) throws {
+        // GIVEN
+        let tasks: [Todo] = []
+        let viewModel = TaskGroupListView.ViewModel()
+
+        // WHEN
+        let count = viewModel.count(tasks, for: group)
+
+        // THEN
+        #expect(count == 0)
+    }
+
+    @Test(
+        "count returns correct count when filled data",
+        arguments: TodoGroup.allCases
+    )
+    func countWhenFilledData(for group: TodoGroup) throws {
+        // GIVEN
+        let today: Date = .now
+        let tomorrow = calendar.date(byAdding: .day, value: 1, to: today) ?? today
+        let yesterday = calendar.date(byAdding: .day, value: -1, to: today) ?? today
+        let nextWeek = calendar.date(byAdding: .day, value: 7, to: today) ?? today
+        let lastWeek = calendar.date(byAdding: .day, value: -7, to: today) ?? today
+
+        let tasks = [
+            Todo(title: "Today task #1", due: today),
+            Todo(title: "Today task #2", due: today),
+            Todo(title: "Tomorrow task #1", due: tomorrow),
+            Todo(title: "Next week task #1", due: nextWeek),
+            Todo(title: "Yesterday task #1", due: yesterday),
+            Todo(title: "Last week task #1", due: lastWeek),
+            Todo(title: "Completed task #1", due: tomorrow, completed: today),
+            Todo(title: "Completed task #2", due: yesterday, completed: today)
+        ]
+
+        let viewModel = TaskGroupListView.ViewModel()
+
+        // WHEN
+        let count = viewModel.count(tasks, for: group)
+
+        // THEN
+        #expect(count == 2)
+    }
+
+}