todos/UnitTests/Tests/Extensions/TodoFetchDescriptor+InitsTests.swift

import Foundation
import SwiftData
import Testing

@testable import Todos

@Suite("TodoFetchDescriptor+Inits extension tests")
struct TodoFetchDescriptor_InitsTests {

    // MARK: Initialization tests

    @Test(
        "initialization when empty tasks",
        arguments: TodoGroup.allCases
    )
    @MainActor
    func initializationWhenEmptyTasks(for group: TodoGroup) throws {
        // GIVEN
        let container = try modelContainer
        let context = container.mainContext

        // WHEN
        let descriptor = FetchDescriptor<Todo>(
            group: .today,
            showCompleted: .random()
        )
        let results = try context.fetch(descriptor)

        // THEN
        #expect(results.isEmpty)
    }

    @Test(
        "initialization with show completed disabled",
        arguments: TodoGroup.allCases
    )
    @MainActor
    func initializationWithNoShowCompleted(for group: TodoGroup) throws {
        // GIVEN
        let container = try modelContainer
        let context = container.mainContext

        insert(into: context)

        // WHEN
        let descriptor = FetchDescriptor<Todo>(
            group: group,
            showCompleted: false
        )
        let results = try context.fetch(descriptor)

        // THEN
        #expect(results.count == 2)

        switch group {
            case .completed:
                #expect(results[0].title == "Completed task #2")
                #expect(results[1].title == "Completed task #1")
            case .overdue:
                #expect(results[0].title == "Overdue task #2")
                #expect(results[1].title == "Overdue task #1")
            case .today:
                #expect(results[0].title == "Today task #1")
                #expect(results[1].title == "Today task #2")
            case .upcoming:
                #expect(results[0].title == "Upcoming task #1")
                #expect(results[1].title == "Upcoming task #2")
        }
    }

    @Test(
        "initialization with show completed enabled",
        arguments: TodoGroup.allCases
    )
    @MainActor
    func initializationWithShowCompleted(for group: TodoGroup) throws {
        // GIVEN
        let container = try modelContainer
        let context = container.mainContext

        insert(into: context)

        // WHEN
        let descriptor = FetchDescriptor<Todo>(
            group: group,
            showCompleted: true
        )
        let results = try context.fetch(descriptor)

        // THEN
        if group == .overdue || group == .upcoming {
            #expect(results.count == 3)
        }
        else {
            #expect(results.count == 2)
        }

        switch group {
            case .completed:
                #expect(results[0].title == "Completed task #2")
                #expect(results[1].title == "Completed task #1")
            case .overdue:
                #expect(results[0].title == "Overdue task #2")
                #expect(results[1].title == "Completed task #1")
                #expect(results[2].title == "Overdue task #1")
            case .today:
                #expect(results[0].title == "Today task #1")
                #expect(results[1].title == "Today task #2")
            case .upcoming:
                #expect(results[0].title == "Completed task #2")
                #expect(results[1].title == "Upcoming task #1")
                #expect(results[2].title == "Upcoming task #2")
        }
    }

}

// MARK: - Helpers

private extension TodoFetchDescriptor_InitsTests {

    // MARK: Computed

    var modelContainer: ModelContainer {
        get throws {
            try ModelContainer(
                for: Todo.self,
                configurations: .init(isStoredInMemoryOnly: true)
            )
        }
    }

    // MARK: Functions

    func insert(
        into context: ModelContext,
        calendar: Calendar = .current
    ) {
        let tasks: [Todo] = [
            .init(
                title: "Today task #1",
                due: .now,
                order: 0
            ),
            .init(
                title: "Today task #2",
                due: .now,
                order: 1
            ),
            .init(
                title: "Upcoming task #1",
                due: calendar.date(byAdding: .day, value: 2, to: .now) ?? .now,
                order: 0
            ),
            .init(
                title: "Upcoming task #2",
                due: calendar.date(byAdding: .day, value: 3, to: .now) ?? .now,
                order: 1
            ),
            .init(
                title: "Overdue task #1",
                due: calendar.date(byAdding: .day, value: -1, to: .now) ?? .now,
                order: 1
            ),
            .init(
                title: "Overdue task #2",
                due: calendar.date(byAdding: .day, value: -1, to: .now) ?? .now,
                order: 0
            ),
            .init(
                title: "Completed task #1",
                due: calendar.date(byAdding: .day, value: -1, to: .now) ?? .now,
                completed: .now,
                order: 1
            ),
            .init(
                title: "Completed task #2",
                due: calendar.date(byAdding: .day, value: 1, to: .now) ?? .now,
                completed: .now,
                order: 0
            ),
        ]

        for task in tasks {
            context.insert(task)
        }
    }

}