todos/UnitTests/Tests/View Models/ContentViewModelTests.swift

import SwiftUI
import Testing

@testable import Todos

@MainActor
@Suite("ContentView view model 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)
        #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 newTaskShown to true")
    func newTaskShown() {
        // GIVEN
        let viewModel = ContentView.ViewModel()

        // WHEN
        viewModel.showNewTask()

        // THEN
        #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)
    }

}