yattee/YatteeTests/AccountsScreenTests.swift

//
//  AccountsScreenTests.swift
//  YatteeTests
//
//  The accounts screen's two pieces of logic that are not presentation:
//  removing an account whose source is gone, and disclosing what deleting a
//  source takes with it.
//

import Testing
import Foundation
import SwiftUI
@testable import Yattee

@Suite("Orphaned account removal")
@MainActor
struct OrphanedAccountRemovalTests {
    private func makeDefaults() -> UserDefaults {
        UserDefaults(suiteName: "yattee.tests.\(UUID().uuidString)")!
    }

    private func makeScope() -> CredentialIdentityScope {
        CredentialIdentityScope(fixedScope: "identity-\(UUID().uuidString)")
    }

    private func makeInstance(_ type: InstanceType) -> Instance {
        Instance(type: type, url: URL(string: "https://\(UUID().uuidString).example.com")!)
    }

    @Test("An account outlives its source, and knows nothing about it")
    func orphanHasNothingToResolveThrough() {
        let scope = makeScope()
        let instances = makeTestInstancesManager()
        let instance = makeInstance(.invidious)
        instances.add(instance)

        let accountsManager = AccountsManager(
            identityScope: scope,
            instancesManager: instances,
            defaults: makeDefaults()
        )
        let account = accountsManager.addAccount(instanceID: instance.id)

        instances.remove(instance)

        // Everything the ordinary cascade resolves through is gone with it —
        // which is why removal has to go by account ID rather than by instance.
        #expect(accountsManager.instance(for: account) == nil)
        #expect(accountsManager.capabilities(for: account) == nil)
        #expect(accountsManager.orphanedAccounts.contains { $0.id == account.id })
        #expect(!accountsManager.selectableAccounts.contains { $0.id == account.id })

        accountsManager.removeAccount(account.id)
    }

    @Test("Removing an orphan deletes the credential filed under its ID")
    func removalDeletesTheCredential() {
        let scope = makeScope()
        let invidious = InvidiousCredentialsManager(identityScope: scope)
        let piped = PipedCredentialsManager(identityScope: scope)

        let instances = makeTestInstancesManager()
        let instance = makeInstance(.invidious)
        instances.add(instance)

        let accountsManager = AccountsManager(
            identityScope: scope,
            instancesManager: instances,
            defaults: makeDefaults()
        )
        let account = accountsManager.addAccount(instanceID: instance.id)
        invidious.setCredential("sid-1", for: account)
        #expect(invidious.credential(for: account) != nil)

        instances.remove(instance)

        var discarded: [UUID] = []
        AccountRemoval.removeOrphan(
            account.id,
            stores: [invidious, piped],
            accountsManager: accountsManager,
            discardData: { discarded.append($0) }
        )

        #expect(invidious.credential(for: account) == nil)
        #expect(accountsManager.account(id: account.id) == nil)
        #expect(!accountsManager.orphanedAccounts.contains { $0.id == account.id })
        // The in-memory data goes too, or the account's subscriptions and
        // playlists keep answering for an account nobody has.
        #expect(discarded == [account.id])
    }

    @Test("Every store is asked, because the backend is no longer knowable")
    func removalAsksBothStores() {
        let scope = makeScope()
        let invidious = InvidiousCredentialsManager(identityScope: scope)
        let piped = PipedCredentialsManager(identityScope: scope)

        let instances = makeTestInstancesManager()
        let instance = makeInstance(.piped)
        instances.add(instance)

        let accountsManager = AccountsManager(
            identityScope: scope,
            instancesManager: instances,
            defaults: makeDefaults()
        )
        let account = accountsManager.addAccount(instanceID: instance.id)
        piped.setCredential("token-1", for: account)

        instances.remove(instance)

        AccountRemoval.removeOrphan(
            account.id,
            stores: [invidious, piped],
            accountsManager: accountsManager,
            discardData: { _ in }
        )

        // The instance's type is what said which store to look in, and it is
        // gone — so a Piped orphan must be cleared by a caller that cannot know
        // it was Piped.
        #expect(piped.credential(for: account) == nil)
    }

    @Test("A deletion queued for the server survives the removal")
    func removalQueuesTheTombstone() {
        let scope = makeScope()
        let instances = makeTestInstancesManager()
        let instance = makeInstance(.invidious)
        instances.add(instance)

        let accountsManager = AccountsManager(
            identityScope: scope,
            instancesManager: instances,
            defaults: makeDefaults()
        )
        let account = accountsManager.addAccount(instanceID: instance.id)

        instances.remove(instance)

        AccountRemoval.removeOrphan(
            account.id,
            stores: [],
            accountsManager: accountsManager,
            discardData: { _ in }
        )

        // Removing an orphan is a real deletion, not a local tidy-up: without
        // the tombstone every other device would keep the account and send it
        // back.
        #expect(accountsManager.pendingDeletions.contains(account.id))
    }

    @Test("The deletion is durable before the secret is destroyed")
    func removalRecordsTheTombstoneFirst() {
        let scope = makeScope()
        let instances = makeTestInstancesManager()
        let instance = makeInstance(.invidious)
        instances.add(instance)

        let accountsManager = AccountsManager(
            identityScope: scope,
            instancesManager: instances,
            defaults: makeDefaults()
        )
        let account = accountsManager.addAccount(instanceID: instance.id)

        instances.remove(instance)

        let store = DeletionOrderStore(accountsManager: accountsManager)
        AccountRemoval.removeOrphan(
            account.id,
            stores: [store],
            accountsManager: accountsManager,
            discardData: { _ in }
        )

        // A crash in between would otherwise bring the account back on the next
        // launch — signed out, with no deletion owed to any other device.
        #expect(store.tombstoneWhenDeleted[account.id] == true)
    }

    @Test("The pre-revamp instance-keyed item is deliberately left alone")
    func removalLeavesTheLegacyItem() {
        let scope = makeScope()
        let invidious = InvidiousCredentialsManager(identityScope: scope)

        let instances = makeTestInstancesManager()
        let instance = makeInstance(.invidious)
        instances.add(instance)

        let accountsManager = AccountsManager(
            identityScope: scope,
            instancesManager: instances,
            defaults: makeDefaults()
        )
        let account = accountsManager.addAccount(instanceID: instance.id)

        // The unscoped legacy item is keyed by the instance, and identifying it
        // needs the instance — which is exactly what an orphan is missing.
        invidious.setCredential("legacy-sid", for: instance)
        defer { invidious.deleteCredential(for: instance) }

        instances.remove(instance)

        AccountRemoval.removeOrphan(
            account.id,
            stores: [invidious],
            accountsManager: accountsManager,
            discardData: { _ in }
        )

        #expect(invidious.credential(for: instance) == "legacy-sid")
    }
}

/// A credential store that records what the account manager already knew at the
/// moment it was asked to destroy a secret.
///
/// The ordering is the whole point of the cascade and cannot be observed from
/// its outcome — both orders end in the same state unless the process dies
/// halfway.
@Observable
@MainActor
private final class DeletionOrderStore: AccountCredentialsManager {
    private let accountsManager: AccountsManager
    var tombstoneWhenDeleted: [UUID: Bool] = [:]

    init(accountsManager: AccountsManager) {
        self.accountsManager = accountsManager
    }

    var loggedInAccountIDs: Set<UUID> { [] }
    var isScopeResolved: Bool { true }

    func setCredential(_: String, for _: Account) {}
    func credential(for _: Account) -> String? { nil }
    func deleteCredential(for account: Account) { deleteCredential(forAccountID: account.id) }

    func deleteCredential(forAccountID accountID: UUID) {
        tombstoneWhenDeleted[accountID] = accountsManager.isDeleted(accountID)
            && accountsManager.pendingDeletions.contains(accountID)
    }

    func migrateCredential(forAccountID _: UUID, fromScope _: String) -> Bool { true }
    func deleteCredential(forAccountID _: UUID, inScope _: String) -> Bool { true }
    func resyncCredentialsWithCurrentSetting() {}
    func setUsername(_: String, for _: Account) {}
    func username(for _: Account) -> String? { nil }
    func isLoggedIn(for _: Account) -> Bool { false }
    func refreshLoginStatus(for _: Account) {}
    func hasAdoptableLegacyCredential(for _: Account) -> Bool { false }
    @discardableResult func adoptLegacyCredential(for _: Account) -> Bool { false }
    func deleteLegacyCredentialIfOwned(for _: Account) {}
}

@Suite("Instance deletion disclosure")
struct InstanceDeletionDisclosureTests {
    @Test("A source with no accounts adds nothing to the question")
    func noAccountsSaysNothing() {
        #expect(InstanceDeletionDisclosure.message(accountNames: []) == nil)
    }

    @Test("A single account is counted and named")
    func oneAccountIsNamed() throws {
        let message = try #require(InstanceDeletionDisclosure.message(accountNames: ["me@inv.example.com"]))

        #expect(message.contains("me@inv.example.com"))
        #expect(message.contains("1"))
        // The lead-in would leak its key if the plural variation were malformed.
        #expect(!message.contains("accountsWarning"))
    }

    @Test("Several accounts are counted and all named, one per line")
    func severalAccountsAreNamed() throws {
        let names = ["first@inv.example.com", "second@inv.example.com", "third@inv.example.com"]
        let message = try #require(InstanceDeletionDisclosure.message(accountNames: names))

        for name in names {
            #expect(message.contains(name))
        }
        #expect(message.contains("3"))
        #expect(message.split(separator: "\n").count == names.count + 1)
    }

    @Test("The count reads differently for one than for many")
    func countVariesWithTheNumberOfAccounts() throws {
        let single = try #require(InstanceDeletionDisclosure.message(accountNames: ["a"]))
        let several = try #require(InstanceDeletionDisclosure.message(accountNames: ["a", "b"]))

        let singleLeadIn = try #require(single.split(separator: "\n").first)
        let severalLeadIn = try #require(several.split(separator: "\n").first)

        #expect(singleLeadIn != severalLeadIn)
    }
}

@Suite("Account status badge")
struct AccountStatusBadgeTests {
    @Test("Every status is named, and no two the same")
    func statusesAreNamed() {
        let statuses: [AccountStatus] = [
            .checking, .signedIn, .credentialMissing, .credentialRejected, .unreachable
        ]
        let texts = statuses.map { AccountStatusBadge.text(for: $0) }

        #expect(texts.allSatisfy { !$0.isEmpty })
        #expect(Set(texts).count == statuses.count)
    }

    @Test("Only the states the user has to act on are coloured")
    func onlyActionableStatesAreColoured() {
        #expect(AccountStatusBadge.color(for: .credentialRejected) == .red)
        #expect(AccountStatusBadge.color(for: .unreachable) == .orange)

        // A credential that never arrived on this device is ordinary — tvOS
        // never receives them at all — so it must not read as a fault.
        #expect(AccountStatusBadge.color(for: .credentialMissing) == .secondary)
        #expect(AccountStatusBadge.color(for: .signedIn) == .secondary)
        #expect(AccountStatusBadge.color(for: .checking) == .secondary)
    }
}

// MARK: - Switcher glyph

@Suite("Data context switcher glyph")
struct DataContextSwitcherGlyphTests {
    private let account = DataContext.account(UUID())

    @Test("Local data and a signed-in account read differently")
    func healthyStatesAreToldApart() {
        #expect(DataContextSwitcherGlyph.systemImage(for: .local, validity: .valid) == "person.crop.circle")
        #expect(DataContextSwitcherGlyph.systemImage(for: account, validity: .valid) == "person.crop.circle.fill")
        #expect(DataContextSwitcherGlyph.tint(for: account, validity: .valid) == nil)
    }

    @Test("A state the user has to act on is badged, in the settings entry's colour")
    func actionableStatesAreBadged() {
        let actionable: [DataContextUnavailability] = [.instanceDisabled, .credentialRejected, .unreachable]

        for reason in actionable {
            let validity = DataContextValidity.temporarilyUnavailable(reason)
            #expect(
                DataContextSwitcherGlyph.systemImage(for: account, validity: validity)
                    == "person.crop.circle.badge.exclamationmark"
            )
            #expect(DataContextSwitcherGlyph.tint(for: account, validity: validity) == .orange)
        }
    }

    @Test("A context that is still resolving is not a fault")
    func pendingStatesAreNotBadged() {
        let pending: [DataContextUnavailability] = [.checking, .instancePending, .credentialMissing]

        for reason in pending {
            let validity = DataContextValidity.temporarilyUnavailable(reason)
            #expect(DataContextSwitcherGlyph.systemImage(for: account, validity: validity) == "person.crop.circle.fill")
            #expect(DataContextSwitcherGlyph.tint(for: account, validity: validity) == nil)
        }
    }
}

// MARK: - Switcher labels

@Suite("Data context switcher labels")
@MainActor
struct DataContextSwitcherLabelTests {
    private func makeDefaults() -> UserDefaults {
        UserDefaults(suiteName: "yattee.tests.\(UUID().uuidString)")!
    }

    private func makeScope() -> CredentialIdentityScope {
        CredentialIdentityScope(fixedScope: "identity-\(UUID().uuidString)")
    }

    /// The real managers a label is built from, with storage of their own.
    private func makeFixture() -> (AccountsManager, InstancesManager, DataContextValidator) {
        let instances = makeTestInstancesManager()
        let accounts = AccountsManager(
            identityScope: makeScope(),
            instancesManager: instances,
            defaults: makeDefaults()
        )
        let validator = DataContextValidator(
            accountsManager: accounts,
            instancesManager: instances,
            toastManager: ToastManager()
        )
        return (accounts, instances, validator)
    }

    private func makeInstance(_ host: String) -> Instance {
        Instance(type: .invidious, url: URL(string: "https://\(host)")!)
    }

    private func title(
        _ account: Account,
        _ accounts: AccountsManager,
        _ validator: DataContextValidator,
        usernames: [UUID: String] = [:]
    ) -> String {
        DataContextSwitcherLabels.title(
            for: .account(account.id),
            accountsManager: accounts,
            validator: validator,
            username: { usernames[$0.id] }
        )
    }

    @Test("A name nobody shares is left alone")
    func uniqueNameIsPlain() {
        let (accounts, instances, validator) = makeFixture()
        let instance = makeInstance("inv.example.com")
        instances.add(instance)

        let account = accounts.addAccount(instanceID: instance.id, displayName: "Work")
        accounts.setStatus(.signedIn, for: account.id)

        #expect(title(account, accounts, validator) == "Work")
    }

    @Test("Two sources sharing a name are told apart by their host")
    func sharedNameOnTwoSourcesGetsTheHost() {
        let (accounts, instances, validator) = makeFixture()
        let first = makeInstance("one.example.com")
        let second = makeInstance("two.example.com")
        instances.add(first)
        instances.add(second)

        let a = accounts.addAccount(instanceID: first.id, displayName: "Work")
        let b = accounts.addAccount(instanceID: second.id, displayName: "Work")
        accounts.setStatus(.signedIn, for: a.id)
        accounts.setStatus(.signedIn, for: b.id)

        #expect(title(a, accounts, validator) == "Work · one.example.com")
        #expect(title(b, accounts, validator) == "Work · two.example.com")
    }

    @Test("Two logins on one source are told apart by who they are")
    func sharedNameOnOneSourceGetsTheUsername() {
        let (accounts, instances, validator) = makeFixture()
        let instance = makeInstance("inv.example.com")
        instances.add(instance)

        let a = accounts.addAccount(instanceID: instance.id, displayName: "Work")
        let b = accounts.addAccount(instanceID: instance.id, displayName: "Work")
        accounts.setStatus(.signedIn, for: a.id)
        accounts.setStatus(.signedIn, for: b.id)

        let usernames = [a.id: "alice", b.id: "bob"]

        // The host is what they have in common, so a host suffix would leave
        // the user choosing between two identical rows.
        #expect(title(a, accounts, validator, usernames: usernames) == "Work · alice@inv.example.com")
        #expect(title(b, accounts, validator, usernames: usernames) == "Work · bob@inv.example.com")
    }

    @Test("A status the user has to act on is named in the label")
    func statusIsAppended() {
        let (accounts, instances, validator) = makeFixture()
        let instance = makeInstance("inv.example.com")
        instances.add(instance)

        let account = accounts.addAccount(instanceID: instance.id, displayName: "Work")
        accounts.setStatus(.credentialRejected, for: account.id)

        let label = title(account, accounts, validator)
        #expect(label.hasPrefix("Work"))
        #expect(label.contains(AccountStatusBadge.text(for: .credentialRejected)))
    }

    @Test("The identifier is preferred, the host is the fallback")
    func disambiguationPrefersTheIdentifier() {
        #expect(
            DataContextSwitcherLabels.disambiguated("Work", username: "alice", host: "inv.example.com")
                == "Work · alice@inv.example.com"
        )
        #expect(
            DataContextSwitcherLabels.disambiguated("Work", username: nil, host: "inv.example.com")
                == "Work · inv.example.com"
        )
        #expect(DataContextSwitcherLabels.disambiguated("Work", username: "alice", host: nil) == "Work · alice")
    }

    @Test("A name that already carries the host does not repeat it")
    func hostIsNotRepeated() {
        #expect(
            DataContextSwitcherLabels.disambiguated("inv.example.com", username: nil, host: "inv.example.com")
                == "inv.example.com"
        )

        // The identifier still adds something the name does not have — the
        // host it is usually paired with does not.
        #expect(
            DataContextSwitcherLabels.disambiguated("inv.example.com", username: "alice", host: "inv.example.com")
                == "inv.example.com · alice"
        )
    }

    @Test("A name that already is the identifier and the host is not doubled")
    func defaultNameIsNotRepeated() {
        #expect(
            DataContextSwitcherLabels.disambiguated(
                "alice@inv.example.com",
                username: "alice",
                host: "inv.example.com"
            ) == "alice@inv.example.com"
        )

        #expect(
            DataContextSwitcherLabels.disambiguated(
                "alice@inv.example.com",
                username: "alice",
                host: "inv.example.com",
                source: "Backup"
            ) == "alice@inv.example.com · Backup"
        )

        // The source names nothing the name does not already say.
        #expect(
            DataContextSwitcherLabels.disambiguated("Work", username: nil, host: nil, source: "Work") == "Work"
        )
    }

    @Test("The same login on two copies of one source is told apart by the source")
    func duplicateSourceAccountsAreToldApart() {
        let (accounts, instances, validator) = makeFixture()
        var first = makeInstance("inv.example.com")
        first.name = "Invidious"
        var second = makeInstance("inv.example.com")
        second.name = "Backup"
        instances.add(first)
        instances.add(second)

        let a = accounts.addAccount(instanceID: first.id, displayName: "alice@inv.example.com")
        let b = accounts.addAccount(instanceID: second.id, displayName: "alice@inv.example.com")
        accounts.setStatus(.signedIn, for: a.id)
        accounts.setStatus(.signedIn, for: b.id)

        let usernames = [a.id: "alice", b.id: "alice"]

        let labelA = title(a, accounts, validator, usernames: usernames)
        let labelB = title(b, accounts, validator, usernames: usernames)

        #expect(labelA == "alice@inv.example.com · Invidious")
        #expect(labelB == "alice@inv.example.com · Backup")
        #expect(labelA != labelB)
    }

    @Test("An account on a switched-off source does not read as signed in")
    func disabledSourceIsNamedInTheLabel() {
        let (accounts, instances, validator) = makeFixture()
        var instance = makeInstance("inv.example.com")
        instance.isEnabled = false
        instances.add(instance)

        let account = accounts.addAccount(instanceID: instance.id, displayName: "Work")
        accounts.setStatus(.signedIn, for: account.id)

        #expect(
            title(account, accounts, validator)
                == "Work — \(AccountStatusBadge.text(for: .instanceDisabled))"
        )
    }
}

// MARK: - Rename

@Suite("Account rename")
@MainActor
struct AccountRenameTests {
    private func makeDefaults() -> UserDefaults {
        UserDefaults(suiteName: "yattee.tests.\(UUID().uuidString)")!
    }

    private func makeScope() -> CredentialIdentityScope {
        CredentialIdentityScope(fixedScope: "identity-\(UUID().uuidString)")
    }

    private func makeFixture() -> (AccountsManager, InstancesManager, DataContextValidator) {
        let instances = makeTestInstancesManager()
        let accounts = AccountsManager(
            identityScope: makeScope(),
            instancesManager: instances,
            defaults: makeDefaults()
        )
        let validator = DataContextValidator(
            accountsManager: accounts,
            instancesManager: instances,
            toastManager: ToastManager()
        )
        return (accounts, instances, validator)
    }

    @Test("A typed name replaces the fallback")
    func typedNameIsStored() {
        #expect(
            DataContextValidator.renamedDisplayName(
                "  Main i01 ",
                prefilledWith: "i01",
                hasUserSetLabel: false
            ) == "Main i01"
        )
    }

    @Test("An empty field clears the label")
    func emptyClearsTheLabel() {
        for hasLabel in [true, false] {
            #expect(
                DataContextValidator.renamedDisplayName(
                    "",
                    prefilledWith: "i01",
                    hasUserSetLabel: hasLabel
                ) == nil
            )
            #expect(
                DataContextValidator.renamedDisplayName(
                    "   \n ",
                    prefilledWith: "Main i01",
                    hasUserSetLabel: hasLabel
                ) == nil
            )
        }
    }

    @Test("Saving an unnamed account's prefill untouched sets no name at all")
    func unchangedFallbackIsNotStored() {
        // The field starts on the label the row is showing, and on an account
        // with no user-set label that is device-local — the login identifier
        // only exists where the credential does. Storing it would publish one
        // device's fallback to every other device as if the user had chosen it.
        #expect(
            DataContextValidator.renamedDisplayName(
                "i01",
                prefilledWith: "i01",
                hasUserSetLabel: false
            ) == nil
        )
        #expect(
            DataContextValidator.renamedDisplayName(
                "  utest1@i01.v.yattee.stream  ",
                prefilledWith: "utest1@i01.v.yattee.stream",
                hasUserSetLabel: false
            ) == nil
        )
    }

    @Test("Typing a name that happens to match this device's fallback still stores it")
    func editedNameEqualToTheDefaultIsStored() {
        // The rule is editedness, not equality with the default. On a second
        // device the string that device falls back to is an ordinary name to
        // choose — and the prefill there is the *synced* label, so typing over
        // it is a real edit that has to store and sync like any other.
        #expect(
            DataContextValidator.renamedDisplayName(
                "i01",
                prefilledWith: "Main i01",
                hasUserSetLabel: true
            ) == "i01"
        )
        // Same on an account with no label yet: the prefill was the fallback
        // "utest1@…", and the user replaced it with something else entirely.
        #expect(
            DataContextValidator.renamedDisplayName(
                "i01",
                prefilledWith: "utest1@i01.v.yattee.stream",
                hasUserSetLabel: false
            ) == "i01"
        )
    }

    @Test("Saving a named account untouched keeps its name rather than clearing it")
    func unchangedNameIsKept() {
        // Decided semantics for "Save with no edit" on an account that already
        // carries a label: re-state the label. The manager drops the write as a
        // no-op, so the name survives and nothing is queued — an idle tap must
        // never read as "clear the name".
        #expect(
            DataContextValidator.renamedDisplayName(
                "Main i01",
                prefilledWith: "Main i01",
                hasUserSetLabel: true
            ) == "Main i01"
        )
    }

    @Test("Both rename surfaces offer the shown label and fall back to the default")
    func renameRequestIsBuiltFromTheValidator() {
        let (accounts, instances, validator) = makeFixture()
        var instance = Instance(type: .invidious, url: URL(string: "https://inv.example.com")!)
        instance.name = "My Invidious"
        instances.add(instance)

        let account = accounts.addAccount(instanceID: instance.id)

        let unnamed = AccountRenameRequest.forAccount(account, resolvedBy: validator)
        #expect(unnamed.id == account.id)
        #expect(unnamed.defaultName == validator.defaultDisplayName(for: account))
        #expect(unnamed.initialText == validator.displayName(for: account))
        #expect(unnamed.hasUserSetLabel == false)

        accounts.updateDisplayName("Main i01", for: account.id)
        let renamed = accounts.account(id: account.id)!

        let named = AccountRenameRequest.forAccount(renamed, resolvedBy: validator)
        // The placeholder stays the *default*, never the label being edited:
        // clearing the field has to advertise where it lands.
        #expect(named.defaultName == "My Invidious")
        #expect(named.initialText == "Main i01")
        #expect(named.hasUserSetLabel)
    }

    @Test("An orphan's rename request offers only its own label")
    func orphanRenameRequestSkipsTheValidator() {
        let (accounts, instances, _) = makeFixture()
        let instance = Instance(type: .invidious, url: URL(string: "https://inv.example.com")!)
        instances.add(instance)

        let account = accounts.addAccount(instanceID: instance.id)
        let unnamed = AccountRenameRequest.forAccount(account, fallingBackTo: "Unnamed")
        #expect(unnamed.defaultName == "Unnamed")
        #expect(unnamed.initialText.isEmpty)
        #expect(unnamed.hasUserSetLabel == false)

        accounts.updateDisplayName("Abandoned login", for: account.id)
        let named = AccountRenameRequest.forAccount(
            accounts.account(id: account.id)!,
            fallingBackTo: "Unnamed"
        )
        #expect(named.initialText == "Abandoned login")
        #expect(named.hasUserSetLabel)
    }

    @Test("Re-saving the same name writes nothing")
    func noOpSaveIsNotWritten() {
        let (accounts, instances, _) = makeFixture()
        let instance = Instance(type: .invidious, url: URL(string: "https://inv.example.com")!)
        instances.add(instance)

        let account = accounts.addAccount(instanceID: instance.id)

        // An untouched save on an account with no label: nil over nil.
        accounts.confirmUpload(account.id)
        let untouchedAt = accounts.account(id: account.id)?.updatedAt
        accounts.updateDisplayName(nil, for: account.id)
        #expect(!accounts.pendingUploads.contains(account.id))
        #expect(accounts.account(id: account.id)?.updatedAt == untouchedAt)

        accounts.updateDisplayName("Main i01", for: account.id)
        accounts.confirmUpload(account.id)
        let renamedAt = accounts.account(id: account.id)?.updatedAt

        // And on one that carries a label: the same string over itself.
        accounts.updateDisplayName("Main i01", for: account.id)
        #expect(!accounts.pendingUploads.contains(account.id))
        #expect(accounts.account(id: account.id)?.updatedAt == renamedAt)
        #expect(accounts.account(id: account.id)?.displayName == "Main i01")
    }

    @Test("The default name ignores the user-set one, and the shown name prefers it")
    func defaultIgnoresTheUserSetLabel() {
        let (accounts, instances, validator) = makeFixture()
        var instance = Instance(type: .invidious, url: URL(string: "https://inv.example.com")!)
        instance.name = "My Invidious"
        instances.add(instance)

        let account = accounts.addAccount(instanceID: instance.id)

        #expect(validator.defaultDisplayName(for: account) == "My Invidious")
        #expect(validator.displayName(for: account) == "My Invidious")

        accounts.updateDisplayName("Main i01", for: account.id)
        let renamed = accounts.account(id: account.id)!

        #expect(validator.displayName(for: renamed) == "Main i01")
        // Unchanged: clearing the name has somewhere to go back to.
        #expect(validator.defaultDisplayName(for: renamed) == "My Invidious")
    }

    @Test("A rename is queued for upload, and clearing it is queued too")
    func renameIsQueuedForUpload() {
        let (accounts, instances, _) = makeFixture()
        let instance = Instance(type: .invidious, url: URL(string: "https://inv.example.com")!)
        instances.add(instance)

        let account = accounts.addAccount(instanceID: instance.id)
        accounts.confirmUpload(account.id)
        #expect(!accounts.pendingUploads.contains(account.id))

        accounts.updateDisplayName("Main i01", for: account.id)
        #expect(accounts.pendingUploads.contains(account.id))
        #expect(accounts.account(id: account.id)?.displayName == "Main i01")

        accounts.confirmUpload(account.id)
        accounts.updateDisplayName(nil, for: account.id)
        #expect(accounts.pendingUploads.contains(account.id))
        #expect(accounts.account(id: account.id)?.displayName == nil)
    }
}