Path: blob/main/SignalUI/LinkPreview/LinkPreviewFetchStateTest.swift
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//
// Copyright 2023 Signal Messenger, LLC
// SPDX-License-Identifier: AGPL-3.0-only
//
import XCTest
@testable import SignalServiceKit
@testable import SignalUI
private extension LinkPreviewFetchState.State {
var isNone: Bool {
if case .none = self {
return true
}
return false
}
var isLoaded: Bool {
if case .loaded = self {
return true
}
return false
}
var isFailed: Bool {
if case .failed = self {
return true
}
return false
}
var isLoading: Bool {
if case .loading = self {
return true
}
return false
}
}
class LinkPreviewFetchStateTest: XCTestCase {
private var mockLinkPreviewFetcher: MockLinkPreviewFetcher!
private var mockDB: InMemoryDB!
override func setUp() {
super.setUp()
mockDB = InMemoryDB()
mockLinkPreviewFetcher = MockLinkPreviewFetcher()
}
private func linkPreviewFetchState(
areLinkPreviewsEnabled: Bool = true,
onlyParseIfEnabled: Bool = false,
) -> LinkPreviewFetchState {
let linkPreviewSettingStore = LinkPreviewSettingStore.mock()
mockDB.write { tx in
linkPreviewSettingStore.setAreLinkPreviewsEnabled(areLinkPreviewsEnabled, tx: tx)
}
return LinkPreviewFetchState(
db: mockDB,
linkPreviewFetcher: mockLinkPreviewFetcher,
linkPreviewSettingStore: linkPreviewSettingStore,
onlyParseIfEnabled: onlyParseIfEnabled,
linkPreviewDraft: nil,
)
}
func testUpdateLoaded() async throws {
let linkPreviewFetchState = self.linkPreviewFetchState()
// Non-URL text shouldn't issue any fetches.
for textValue in ["a", "ab", "abc"] {
await linkPreviewFetchState.update(.init(text: textValue, ranges: .empty))?.value
XCTAssert(linkPreviewFetchState.currentState.isNone)
XCTAssertNil(linkPreviewFetchState.linkPreviewDraftIfLoaded)
XCTAssertNil(linkPreviewFetchState.currentUrl)
XCTAssertEqual(mockLinkPreviewFetcher.fetchedURLs, [])
}
// A valid URL should fetch only once, even if the text is modified.
let validURL = try XCTUnwrap(URL(string: "https://signal.org"))
mockLinkPreviewFetcher.fetchLinkPreviewBlock = { fetchedURL in
XCTAssertEqual(fetchedURL, validURL)
return OWSLinkPreviewDraft(url: fetchedURL, title: "Website Title", isForwarded: false)
}
for textValue in ["Check ou https://signal.org", "Check out https://signal.org"] {
await linkPreviewFetchState.update(.init(text: textValue, ranges: .empty))?.value
XCTAssert(linkPreviewFetchState.currentState.isLoaded)
XCTAssertEqual(linkPreviewFetchState.linkPreviewDraftIfLoaded?.url, validURL)
XCTAssertEqual(linkPreviewFetchState.currentUrl, validURL)
XCTAssertEqual(mockLinkPreviewFetcher.fetchedURLs, [validURL])
}
// An invalid URL should fetch only once, even if the text is modified.
let invalidURL = try XCTUnwrap(URL(string: "https://signal.org/not_found"))
mockLinkPreviewFetcher.fetchLinkPreviewBlock = { fetchedURL in
XCTAssertEqual(fetchedURL, invalidURL)
throw OWSGenericError("Not found.")
}
for textValue in ["Check ou https://signal.org/not_found", "Check out https://signal.org/not_found"] {
await linkPreviewFetchState.update(.init(text: textValue, ranges: .empty))?.value
XCTAssert(linkPreviewFetchState.currentState.isFailed)
XCTAssertNil(linkPreviewFetchState.linkPreviewDraftIfLoaded)
XCTAssertEqual(linkPreviewFetchState.currentUrl, invalidURL)
XCTAssertEqual(mockLinkPreviewFetcher.fetchedURLs, [validURL, invalidURL])
}
// Removing the URL should clear the link preview.
for textValue in ["Check out", "Check ou"] {
await linkPreviewFetchState.update(.init(text: textValue, ranges: .empty))?.value
XCTAssert(linkPreviewFetchState.currentState.isNone)
XCTAssertNil(linkPreviewFetchState.linkPreviewDraftIfLoaded)
XCTAssertNil(linkPreviewFetchState.currentUrl)
XCTAssertEqual(mockLinkPreviewFetcher.fetchedURLs, [validURL, invalidURL])
}
}
private struct PendingFetchState {
var isReady = false
var deferredBlocks = [() -> Void]()
var expectedCount: Int
mutating func resolveIfReady() {
guard self.isReady, self.deferredBlocks.count == self.expectedCount else {
return
}
self.deferredBlocks.forEach { $0() }
self.deferredBlocks.removeAll()
}
}
func testUpdateLoading() async throws {
let linkPreviewFetchState = self.linkPreviewFetchState()
let validURL = try XCTUnwrap(URL(string: "https://signal.org"))
let pendingFetchState = AtomicValue(PendingFetchState(expectedCount: 1), lock: .init())
mockLinkPreviewFetcher.fetchLinkPreviewBlock = { fetchedURL in
return try await withCheckedThrowingContinuation { continuation in
pendingFetchState.update {
$0.deferredBlocks.append {
continuation.resume(returning: OWSLinkPreviewDraft(url: fetchedURL, title: "Website Title", isForwarded: false))
}
$0.resolveIfReady()
}
}
}
let task1 = linkPreviewFetchState.update(.init(text: "https://signal.org is a grea", ranges: .empty))
XCTAssert(linkPreviewFetchState.currentState.isLoading)
// If there's a request in flight, we shouldn't send a new request.
let task2 = linkPreviewFetchState.update(.init(text: "https://signal.org is a great", ranges: .empty))
XCTAssert(linkPreviewFetchState.currentState.isLoading)
pendingFetchState.update {
$0.isReady = true
$0.resolveIfReady()
}
await task1?.value
await task2?.value
XCTAssert(linkPreviewFetchState.currentState.isLoaded)
XCTAssertEqual(mockLinkPreviewFetcher.fetchedURLs, [validURL])
}
func testUpdateObsolete() async throws {
let linkPreviewFetchState = self.linkPreviewFetchState()
let pendingFetchState = AtomicValue(PendingFetchState(expectedCount: 2), lock: .init())
mockLinkPreviewFetcher.fetchLinkPreviewBlock = { fetchedURL in
return try await withCheckedThrowingContinuation { continuation in
pendingFetchState.update {
$0.deferredBlocks.append {
continuation.resume(returning: OWSLinkPreviewDraft(url: fetchedURL, title: "Website Title", isForwarded: false))
}
$0.resolveIfReady()
}
}
}
let url1 = try XCTUnwrap(URL(string: "https://signal.org/one"))
let task1 = linkPreviewFetchState.update(.init(text: "https://signal.org/one", ranges: .empty))
XCTAssert(linkPreviewFetchState.currentState.isLoading)
// If there's a request in flight & we change the URL, drop the original request.
let url2 = try XCTUnwrap(URL(string: "https://signal.org/two"))
let task2 = linkPreviewFetchState.update(.init(text: "https://signal.org/two", ranges: .empty))
XCTAssert(linkPreviewFetchState.currentState.isLoading)
pendingFetchState.update {
$0.isReady = true
$0.resolveIfReady()
}
await task1?.value
await task2?.value
XCTAssert(linkPreviewFetchState.currentState.isLoaded)
XCTAssertEqual(linkPreviewFetchState.linkPreviewDraftIfLoaded?.url, url2)
XCTAssertEqual(linkPreviewFetchState.currentUrl, url2)
XCTAssertEqual(Set(mockLinkPreviewFetcher.fetchedURLs), [url1, url2])
}
func testUpdatePrependScheme() async throws {
let linkPreviewFetchState = self.linkPreviewFetchState()
mockLinkPreviewFetcher.fetchLinkPreviewBlock = { fetchedURL in
return OWSLinkPreviewDraft(url: fetchedURL, title: "Signal", isForwarded: false)
}
await linkPreviewFetchState.update(.init(text: "signal.org", ranges: .empty), prependSchemeIfNeeded: false)?.value
XCTAssert(linkPreviewFetchState.currentState.isNone)
XCTAssertEqual(mockLinkPreviewFetcher.fetchedURLs, [])
// If we should prepend a scheme, prepend "https://".
await linkPreviewFetchState.update(.init(text: "signal.org", ranges: .empty), prependSchemeIfNeeded: true)?.value
XCTAssert(linkPreviewFetchState.currentState.isLoaded)
XCTAssertEqual(mockLinkPreviewFetcher.fetchedURLs, [URL(string: "https://signal.org")!])
mockLinkPreviewFetcher._fetchedURLs.update { $0.removeAll() }
// If there's already a scheme, we don't add "https://". (We require
// "https://", so specify anything other scheme disables link previews.
await linkPreviewFetchState.update(.init(text: "http://signal.org", ranges: .empty), prependSchemeIfNeeded: true)?.value
XCTAssert(linkPreviewFetchState.currentState.isNone)
XCTAssertEqual(mockLinkPreviewFetcher.fetchedURLs, [])
}
func testOnStateChange() async throws {
let linkPreviewFetchState = self.linkPreviewFetchState()
mockLinkPreviewFetcher.fetchLinkPreviewBlock = { fetchedURL in
return OWSLinkPreviewDraft(url: fetchedURL, title: "Signal", isForwarded: false)
}
var onStateChangeCount = 0
linkPreviewFetchState.onStateChange = { onStateChangeCount += 1 }
await linkPreviewFetchState.update(.init(text: "", ranges: .empty))?.value
XCTAssertEqual(onStateChangeCount, 0)
// Redundant updates generally don't result in state updates.
await linkPreviewFetchState.update(.init(text: "a", ranges: .empty))?.value
XCTAssertEqual(onStateChangeCount, 0)
// Fetching a URL should update the state twice: to loading & to loaded.
await linkPreviewFetchState.update(.init(text: "https://signal.org", ranges: .empty))?.value
XCTAssertEqual(onStateChangeCount, 2)
await linkPreviewFetchState.update(.init(text: "https://signal.org", ranges: .empty))?.value
XCTAssertEqual(onStateChangeCount, 2)
// Clearing the text should update the link preview.
await linkPreviewFetchState.update(.init(text: "", ranges: .empty))?.value
XCTAssertEqual(onStateChangeCount, 3)
// Assigning the URL again should fetch it again.
await linkPreviewFetchState.update(.init(text: "https://signal.org", ranges: .empty))?.value
XCTAssertEqual(onStateChangeCount, 5)
// Disabling the link preview should trigger an update.
linkPreviewFetchState.disable()
XCTAssertEqual(onStateChangeCount, 6)
}
func testDisable() async throws {
let linkPreviewFetchState = self.linkPreviewFetchState()
mockLinkPreviewFetcher.fetchLinkPreviewBlock = { fetchedURL in
return OWSLinkPreviewDraft(url: fetchedURL, title: "Signal", isForwarded: false)
}
// Fetch the original preview.
let url = try XCTUnwrap(URL(string: "https://signal.org"))
await linkPreviewFetchState.update(.init(text: "https://signal.org", ranges: .empty))?.value
XCTAssertEqual(linkPreviewFetchState.linkPreviewDraftIfLoaded?.url, url)
XCTAssertEqual(mockLinkPreviewFetcher.fetchedURLs, [url])
mockLinkPreviewFetcher._fetchedURLs.update { $0.removeAll() }
// Dismiss the preview; make sure it goes away.
linkPreviewFetchState.disable()
XCTAssertNil(linkPreviewFetchState.linkPreviewDraftIfLoaded)
XCTAssertEqual(mockLinkPreviewFetcher.fetchedURLs, [])
// Assign the same URL again; make sure it doesn't come back.
await linkPreviewFetchState.update(.init(text: "https://signal.org", ranges: .empty))?.value
XCTAssertNil(linkPreviewFetchState.linkPreviewDraftIfLoaded)
XCTAssertEqual(mockLinkPreviewFetcher.fetchedURLs, [])
// Clear the URL; make sure it stays away.
await linkPreviewFetchState.update(.init(text: "", ranges: .empty))?.value
XCTAssertNil(linkPreviewFetchState.linkPreviewDraftIfLoaded)
XCTAssertEqual(mockLinkPreviewFetcher.fetchedURLs, [])
// Enter a different URL; make sure we don't fetch it.
await linkPreviewFetchState.update(.init(text: "https://signal.org/one", ranges: .empty))?.value
XCTAssertNil(linkPreviewFetchState.linkPreviewDraftIfLoaded)
XCTAssertEqual(mockLinkPreviewFetcher.fetchedURLs, [])
// Ensure "enableIfEmpty" doesn't enable when the text isn't empty.
await linkPreviewFetchState.update(.init(text: "https://signal.org/one", ranges: .empty), enableIfEmpty: true)?.value
XCTAssertNil(linkPreviewFetchState.linkPreviewDraftIfLoaded)
XCTAssertEqual(mockLinkPreviewFetcher.fetchedURLs, [])
// Clear the text with "enableIfEmpty" to re-enable link previews.
await linkPreviewFetchState.update(.init(text: "", ranges: .empty), enableIfEmpty: true)?.value
XCTAssertNil(linkPreviewFetchState.linkPreviewDraftIfLoaded)
XCTAssertEqual(mockLinkPreviewFetcher.fetchedURLs, [])
// Set a URL and make sure we fetch it.
let url2 = try XCTUnwrap(URL(string: "https://signal.org/two"))
await linkPreviewFetchState.update(.init(text: "https://signal.org/two", ranges: .empty), enableIfEmpty: true)?.value
XCTAssertEqual(linkPreviewFetchState.linkPreviewDraftIfLoaded?.url, url2)
XCTAssertEqual(mockLinkPreviewFetcher.fetchedURLs, [url2])
}
func testOnlyParseIfEnabled() async throws {
do {
let linkPreviewFetchState = self.linkPreviewFetchState(
areLinkPreviewsEnabled: false,
onlyParseIfEnabled: true,
)
await linkPreviewFetchState.update(.init(text: "https://signal.org", ranges: .empty))?.value
XCTAssertNil(linkPreviewFetchState.currentUrl)
}
do {
let linkPreviewFetchState = self.linkPreviewFetchState(
areLinkPreviewsEnabled: false,
onlyParseIfEnabled: false,
)
// If link previews are disabled, we may still want to parse URLs in the
// text so that they can be attached (without a preview) to text stories.
mockLinkPreviewFetcher.fetchLinkPreviewBlock = { fetchedURL in
throw OWSGenericError("Not found.")
}
await linkPreviewFetchState.update(.init(text: "https://signal.org", ranges: .empty))?.value
XCTAssertEqual(linkPreviewFetchState.currentUrl, try XCTUnwrap(URL(string: "https://signal.org")))
}
}
func testDontParseInSpoilers() async throws {
mockLinkPreviewFetcher.fetchLinkPreviewBlock = { fetchedURL in
return OWSLinkPreviewDraft(url: fetchedURL, title: "Signal", isForwarded: false)
}
let linkPreviewFetchState = self.linkPreviewFetchState(
onlyParseIfEnabled: true,
)
// Bold should have no effect
await linkPreviewFetchState.update(.init(
text: "https://signal.org",
ranges: .init(
mentions: [:],
styles: [.init(.bold, range: NSRange(location: 0, length: 18))],
),
))?.value
XCTAssertNotNil(linkPreviewFetchState.currentUrl)
// Spoiler should mean we don't match.
await linkPreviewFetchState.update(.init(
text: "https://signal.org",
ranges: .init(
mentions: [:],
styles: [.init(.spoiler, range: NSRange(location: 0, length: 18))],
),
))?.value
XCTAssertNil(linkPreviewFetchState.currentUrl)
// Even if only partially covering.
await linkPreviewFetchState.update(.init(
text: "https://signal.org",
ranges: .init(
mentions: [:],
styles: [.init(.spoiler, range: NSRange(location: 3, length: 5))],
),
))?.value
XCTAssertNil(linkPreviewFetchState.currentUrl)
// Including if we prepend a prefix.
await linkPreviewFetchState.update(.init(
text: "signal.org",
ranges: .init(
mentions: [:],
styles: [.init(.spoiler, range: NSRange(location: 5, length: 5))],
),
))?.value
XCTAssertNil(linkPreviewFetchState.currentUrl)
}
}