app-reviews/Frameworks/Feed/Test/Tests/View Models/FeedListViewModelTests.swift

//
//  FeedListViewModelTests.swift
//  ReviewsFeedTests
//
//  Created by Javier Cicchelli on 22/03/2024.
//  Copyright © 2024 Röck+Cöde. All rights reserved.
//

import Combine
import ReviewsFoundationKit
import ReviewsiTunesKit
import XCTest

@testable import ReviewsFeed

final class FeedListViewModelTests: XCTestCase {
    
    // MARK: Properties
    private var sut: FeedListViewController.ViewModel!
    
    private var cancellables: Set<AnyCancellable> = []

    // MARK: Setup
    override func setUp() async throws {
        sut = .init(
            configuration: .init(session: .mock),
            coordination: nil
        )
    }
    
    override func tearDown() async throws {
        cancellables.removeAll()
    }
    
    // MARK: Initialisers tests
    func testInit() {
        // GIVEN
        // WHEN
        // THEN
        XCTAssertEqual(sut.filter, .all)
        XCTAssertFalse(sut.isFilterEnabled)
        XCTAssertFalse(sut.isFiltering)
        XCTAssertFalse(sut.isLoading)
        XCTAssertFalse(sut.isWordsShowing)
        XCTAssertTrue(sut.items.isEmpty)
        XCTAssertEqual(sut.itemsCount, 0)
        XCTAssertEqual(sut.state, .initial)
        XCTAssertTrue(sut.words.isEmpty)
    }
    
    // MARK: Functions tests
    func testFetch_allItems_whenResponseOK_withSomeItems() {
        let expectation = XCTestExpectation()
        
        var isLoading: [Bool] = []
        
        // GIVEN
        MockURLProtocol.response = .init(
            statusCode: 200,
            object: Feed(entries: .sample)
        )
        
        // WHEN
        sut.fetch()
        
        sut.$isLoading
            .collect(3)
            .sink { value in
                isLoading.append(contentsOf: value)
                
                expectation.fulfill()
            }
            .store(in: &cancellables)
        
        wait(for: [expectation], timeout: 2)
        
        // THEN
        XCTAssertEqual(isLoading, [false, true, false])
        XCTAssertTrue(sut.isFilterEnabled)
        XCTAssertFalse(sut.isWordsShowing)
        XCTAssertFalse(sut.items.isEmpty)
        XCTAssertEqual(sut.items.count, 5)
        XCTAssertEqual(sut.itemsCount, 5)
        XCTAssertEqual(sut.state, .populated)
    }
    
    func testFetch_allItems_whenResponseOK_withNoItems() {
        let expectation = XCTestExpectation()
        
        var isLoading: [Bool] = []
        
        // GIVEN
        MockURLProtocol.response = .init(
            statusCode: 200,
            object: Feed(entries: .none)
        )

        // WHEN
        sut.fetch()

        sut.$isLoading
            .collect(3)
            .sink { value in
                isLoading.append(contentsOf: value)

                expectation.fulfill()
            }
            .store(in: &cancellables)

        wait(for: [expectation], timeout: 2)
        
        // THEN
        XCTAssertEqual(isLoading, [false, true, false])
        XCTAssertFalse(sut.isFilterEnabled)
        XCTAssertFalse(sut.isWordsShowing)
        XCTAssertTrue(sut.items.isEmpty)
        XCTAssertEqual(sut.itemsCount, 0)
        XCTAssertEqual(sut.state, .empty)
    }
    
    func testFetch_allItems_whenResponseNotOK() {
        let expectation = XCTestExpectation()
        
        var isLoading: [Bool] = []
        
        // GIVEN
        MockURLProtocol.response = .init(statusCode: 404)
        
        // WHEN
        sut.fetch()
        
        sut.$isLoading
            .collect(3)
            .sink { value in
                isLoading.append(contentsOf: value)

                expectation.fulfill()
            }
            .store(in: &cancellables)
        
        wait(for: [expectation], timeout: 2)
        
        // THEN
        XCTAssertEqual(isLoading, [false, true, false])
        XCTAssertFalse(sut.isFilterEnabled)
        XCTAssertFalse(sut.isWordsShowing)
        XCTAssertTrue(sut.items.isEmpty)
        XCTAssertEqual(sut.itemsCount, 0)
        XCTAssertEqual(sut.state, .error)
    }
    
    func testFetch_filteredItems_whenResponseOK_withSomeItems() {
        let expectation = XCTestExpectation()
        
        var isLoading: [Bool] = []
        
        // GIVEN
        sut.filter = .only1Star
        
        MockURLProtocol.response = .init(
            statusCode: 200,
            object: Feed(entries: .sample)
        )
        
        // WHEN
        sut.fetch()
        
        sut.$isLoading
            .collect(3)
            .sink { value in
                isLoading.append(contentsOf: value)
                
                expectation.fulfill()
            }
            .store(in: &cancellables)
        
        wait(for: [expectation], timeout: 2)
        
        // THEN
        XCTAssertEqual(isLoading, [false, true, false])
        XCTAssertTrue(sut.isFilterEnabled)
        XCTAssertTrue(sut.isWordsShowing)
        XCTAssertFalse(sut.items.isEmpty)
        XCTAssertEqual(sut.items.count, 1)
        XCTAssertEqual(sut.itemsCount, 2)
        XCTAssertEqual(sut.state, .populated)
        XCTAssertFalse(sut.words.isEmpty)
        XCTAssertEqual(sut.words.count, 3)
    }
    
    func testFetch_filteredItems_whenResponseOK_withNoItems() {
        let expectation = XCTestExpectation()
        
        var isLoading: [Bool] = []
        
        // GIVEN
        sut.filter = .only1Star
        
        MockURLProtocol.response = .init(
            statusCode: 200,
            object: Feed(entries: .none)
        )
        
        // WHEN
        sut.fetch()
        
        sut.$isLoading
            .collect(3)
            .sink { value in
                isLoading.append(contentsOf: value)
                
                expectation.fulfill()
            }
            .store(in: &cancellables)
        
        wait(for: [expectation], timeout: 2)
        
        // THEN
        XCTAssertEqual(isLoading, [false, true, false])
        XCTAssertFalse(sut.isFilterEnabled)
        XCTAssertFalse(sut.isWordsShowing)
        XCTAssertTrue(sut.items.isEmpty)
        XCTAssertEqual(sut.itemsCount, 0)
        XCTAssertEqual(sut.state, .empty)
        XCTAssertTrue(sut.words.isEmpty)
    }
    
    func testFetch_filteredItems_whenResponseNotOK() {
        let expectation = XCTestExpectation()
        
        var isLoading: [Bool] = []
        
        // GIVEN
        sut.filter = .only1Star
        
        MockURLProtocol.response = .init(statusCode: 404)
        
        // WHEN
        sut.fetch()
        
        sut.$isLoading
            .collect(3)
            .sink { value in
                isLoading.append(contentsOf: value)
                
                expectation.fulfill()
            }
            .store(in: &cancellables)
        
        wait(for: [expectation], timeout: 2)
        
        // THEN
        XCTAssertEqual(isLoading, [false, true, false])
        XCTAssertFalse(sut.isFilterEnabled)
        XCTAssertFalse(sut.isWordsShowing)
        XCTAssertTrue(sut.items.isEmpty)
        XCTAssertEqual(sut.itemsCount, 0)
        XCTAssertEqual(sut.state, .error)
        XCTAssertTrue(sut.words.isEmpty)
    }
    
    func test
    
}