essential-feed-case-study/EssentialFeed/EssentialFeedTests/Shared API Infra/URLSessionHTTPClientTests.swift at fdb1a2cb9f04810a8d290ea2cb641372ad6aa251 · essentialdevelopercom/essential-feed-case-study · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
//
// Copyright © Essential Developer. All rights reserved.
//

import XCTest
import EssentialFeed

@MainActor
class URLSessionHTTPClientTests: XCTestCase {

	override func tearDown() {
		super.tearDown()

		URLProtocolStub.removeStub()
	}

	func test_getFromURL_performsGETRequestWithURL() async throws {
		let url = anyURL()
		let exp = expectation(description: "Wait for request")

		URLProtocolStub.observeRequests { request in
			XCTAssertEqual(request.url, url)
			XCTAssertEqual(request.httpMethod, "GET")
			exp.fulfill()
		}

		_ = try await makeSUT().get(from: url)

		await fulfillment(of: [exp], timeout: 1.0)
	}

	func test_cancelGetFromURLTask_cancelsURLRequest() async {
		var task: Task<(Data, HTTPURLResponse), Error>?
		URLProtocolStub.onStartLoading { task?.cancel() }

		let receivedError = await resultErrorFor(taskHandler: { task = $0 }) as NSError?

		XCTAssertEqual(receivedError?.code, URLError.cancelled.rawValue)
	}

	func test_getFromURL_failsOnRequestError() async {
		let requestError = anyNSError()

		let receivedError = await resultErrorFor((data: nil, response: nil, error: requestError))

		XCTAssertNotNil(receivedError)
	}

	func test_getFromURL_failsOnAllInvalidRepresentationCases() async {
		assertNotNil(await resultErrorFor((data: nil, response: nonHTTPURLResponse(), error: nil)))
		assertNotNil(await resultErrorFor((data: anyData(), response: nil, error: anyNSError())))
		assertNotNil(await resultErrorFor((data: nil, response: nonHTTPURLResponse(), error: anyNSError())))
		assertNotNil(await resultErrorFor((data: nil, response: anyHTTPURLResponse(), error: anyNSError())))
		assertNotNil(await resultErrorFor((data: anyData(), response: nonHTTPURLResponse(), error: anyNSError())))
		assertNotNil(await resultErrorFor((data: anyData(), response: anyHTTPURLResponse(), error: anyNSError())))
		assertNotNil(await resultErrorFor((data: anyData(), response: nonHTTPURLResponse(), error: nil)))
	}

	func test_getFromURL_succeedsOnHTTPURLResponseWithData() async {
		let data = anyData()
		let response = anyHTTPURLResponse()

		let receivedValues = await resultValuesFor((data: data, response: response, error: nil))

		XCTAssertEqual(receivedValues?.data, data)
		XCTAssertEqual(receivedValues?.response.url, response.url)
		XCTAssertEqual(receivedValues?.response.statusCode, response.statusCode)
	}

	func test_getFromURL_succeedsWithEmptyDataOnHTTPURLResponseWithNilData() async {
		let response = anyHTTPURLResponse()

		let receivedValues = await resultValuesFor((data: nil, response: response, error: nil))

		let emptyData = Data()
		XCTAssertEqual(receivedValues?.data, emptyData)
		XCTAssertEqual(receivedValues?.response.url, response.url)
		XCTAssertEqual(receivedValues?.response.statusCode, response.statusCode)
	}

	// MARK: - Helpers

	private func makeSUT(file: StaticString = #filePath, line: UInt = #line) -> HTTPClient {
		let configuration = URLSessionConfiguration.ephemeral
		configuration.protocolClasses = [URLProtocolStub.self]
		let session = URLSession(configuration: configuration)

		let sut = URLSessionHTTPClient(session: session)
		trackForMemoryLeaks(sut, file: file, line: line)
		return sut
	}

	private func resultValuesFor(_ values: (data: Data?, response: URLResponse?, error: Error?), file: StaticString = #filePath, line: UInt = #line) async -> (data: Data, response: HTTPURLResponse)? {
		do {
			let result = try await resultFor(values, file: file, line: line)
			return result
		} catch {
			XCTFail("Expected success, got \(error) instead", file: file, line: line)
			return nil
		}
	}

	private func resultErrorFor(_ values: (data: Data?, response: URLResponse?, error: Error?)? = nil, taskHandler: (Task<(Data, HTTPURLResponse), Error>) -> Void = { _ in }, file: StaticString = #filePath, line: UInt = #line) async -> Error? {
		do {
			let result = try await resultFor(values, taskHandler: taskHandler, file: file, line: line)
			XCTFail("Expected failure, got \(result) instead", file: file, line: line)
			return nil
		} catch {
			return error
		}
	}

	private func resultFor(_ values: (data: Data?, response: URLResponse?, error: Error?)?, taskHandler: (Task<(Data, HTTPURLResponse), Error>) -> Void = { _ in },  file: StaticString = #filePath, line: UInt = #line) async throws -> (Data, HTTPURLResponse) {
		values.map { URLProtocolStub.stub(data: $0, response: $1, error: $2) }

		let sut = makeSUT(file: file, line: line)

		let task = Task {
			return try await sut.get(from: anyURL())
		}
		taskHandler(task)
		return try await task.value
	}

	private func anyHTTPURLResponse() -> HTTPURLResponse {
		return HTTPURLResponse(url: anyURL(), statusCode: 200, httpVersion: nil, headerFields: nil)!
	}

	private func nonHTTPURLResponse() -> URLResponse {
		return URLResponse(url: anyURL(), mimeType: nil, expectedContentLength: 0, textEncodingName: nil)
	}

}

private func assertNotNil(_ value: Any?, _ message: @autoclosure () -> String = "", file: StaticString = #filePath, line: UInt = #line) {
	XCTAssertNotNil(value, message(), file: file, line: line)
}