XCTestCase.fulfillment(…) missing on Linux

[tonyarnold]

Hi folks,

It looks like the fulfillment(…) methods on XCTestCase and XCTWaiter are both missing on Linux.

It would be helpful to have API parity here, as Xcode 14.3 complains if I use the older wait(…) methods:

Instance method 'wait' is unavailable from asynchronous contexts; Use await fulfillment(of:timeout:enforceOrder:) instead; this is an error in Swift 6

Here are the missing methods:

extension XCTestCase {

    /// Waits on a group of expectations for up to the specified timeout,
    /// optionally enforcing their order of fulfillment.
    ///
    /// - Parameters:
    ///     - expectations: An array of expectations that must be fulfilled.
    ///     - seconds: The number of seconds within which all expectations must
    ///         be fulfilled. The default timeout allows the test to run until
    ///         it reaches its execution time allowance.
    ///     - enforceOrderOfFulfillment: If `true`, the expectations specified
    ///         by the `expectations` parameter must be satisfied in the order
    ///         they appear in the array.
    ///
    /// Expectations can only appear in the list once. This function may return
    /// early based on fulfillment of the provided expectations.
    ///
    /// - Note: If you do not specify a timeout when calling this function, it
    ///     is recommended that you enable test timeouts to prevent a runaway
    ///     expectation from hanging the test.
    @available(macOS 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *)
    @nonobjc public func fulfillment(of expectations: [XCTestExpectation], timeout seconds: TimeInterval = .infinity, enforceOrder enforceOrderOfFulfillment: Bool = false) async
}

extension XCTWaiter {

    /// Waits on a group of expectations for up to the specified timeout,
    /// optionally enforcing their order of fulfillment.
    ///
    /// - Parameters:
    ///     - expectations: An array of expectations that must be fulfilled.
    ///     - seconds: The number of seconds within which all expectations must
    ///         be fulfilled. The default timeout allows the test to run until
    ///         it reaches its execution time allowance.
    ///     - enforceOrderOfFulfillment: If `true`, the expectations specified
    ///         by the `expectations` parameter must be satisfied in the order
    ///         they appear in the array.
    ///
    /// - Returns: A value describing the outcome of waiting for `expectations`.
    ///
    /// Expectations can only appear in the list once. This function may return
    /// early based on fulfillment of the provided expectations.
    ///
    /// - Note: If you do not specify a timeout when calling this function, it
    ///     is recommended that you enable test timeouts to prevent a runaway
    ///     expectation from hanging the test.
    @available(macOS 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *)
    @discardableResult
    @nonobjc public func fulfillment(of expectations: [XCTestExpectation], timeout seconds: TimeInterval = .infinity, enforceOrder enforceOrderOfFulfillment: Bool = false) async -> XCTWaiter.Result

    /// Creates a waiter that waits on a group of expectations for up to the
    /// specified timeout, optionally enforcing their order of fulfillment.
    ///
    /// - Parameters:
    ///     - expectations: An array of expectations that must be fulfilled.
    ///     - seconds: The number of seconds within which all expectations must
    ///         be fulfilled. The default timeout allows the test to run until
    ///         it reaches its execution time allowance.
    ///     - enforceOrderOfFulfillment: If `true`, the expectations specified
    ///         by the `expectations` parameter must be satisfied in the order
    ///         they appear in the array.
    ///
    /// - Returns: A value describing the outcome of waiting for `expectations`.
    ///
    /// Expectations can only appear in the list once. This function may return
    /// early based on fulfillment of the provided expectations.
    ///
    /// The waiter is discarded when the wait completes.
    ///
    /// - Note: If you do not specify a timeout when calling this function, it
    ///     is recommended that you enable test timeouts to prevent a runaway
    ///     expectation from hanging the test.
    @available(macOS 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *)
    @nonobjc public class func fulfillment(of expectations: [XCTestExpectation], timeout seconds: TimeInterval = .infinity, enforceOrder enforceOrderOfFulfillment: Bool = false) async -> XCTWaiter.Result
}

[tmaly1980]

I've also checked Xcode 14.2/iOS 16.2 on an M1 and Intel MacBook Pro, and it keeps saying "Cannot find 'fulfillment' in scope" . Any clue why?

[tonyarnold]

@tmaly1980 this seems like a question better asked on StackOverflow than on a specific issue on GitHub, as it's like to be your project configuration at fault (check your minimum deployment targets).

[tonyarnold]

Thanks, @grynspan :heart:

[grynspan]

Always happy to help!

[award999]

@grynspan saw this was merged into main, what are the chances of it making into 5.9? Kind of needed to do asynchronous testing on Linux

[grynspan]

@briancroom is looking into it.

[joshuawright11]

If anyone stumbles upon this before Swift 5.10/whatever release this becomes available, here is the extension I use for support on Linux (based on @grynspan's PR).

When this is officially released, you should just be able to remove the extension.

#if os(Linux)
import XCTest

extension XCTestCase {
    /// Wait on an array of expectations for up to the specified timeout, and optionally specify whether they
    /// must be fulfilled in the given order. May return early based on fulfillment of the waited on expectations.
    ///
    /// - Parameter expectations: The expectations to wait on.
    /// - Parameter timeout: The maximum total time duration to wait on all expectations.
    /// - Parameter enforceOrder: Specifies whether the expectations must be fulfilled in the order
    ///   they are specified in the `expectations` Array. Default is false.
    /// - Parameter file: The file name to use in the error message if
    ///   expectations are not fulfilled before the given timeout. Default is the file
    ///   containing the call to this method. It is rare to provide this
    ///   parameter when calling this method.
    /// - Parameter line: The line number to use in the error message if the
    ///   expectations are not fulfilled before the given timeout. Default is the line
    ///   number of the call to this method in the calling file. It is rare to
    ///   provide this parameter when calling this method.
    ///
    /// - SeeAlso: XCTWaiter
    func fulfillment(of expectations: [XCTestExpectation], timeout: TimeInterval, enforceOrder: Bool = false) async {
        return await withCheckedContinuation { continuation in
            // This function operates by blocking a background thread instead of one owned by libdispatch or by the
            // Swift runtime (as used by Swift concurrency.) To ensure we use a thread owned by neither subsystem, use
            // Foundation's Thread.detachNewThread(_:).
            Thread.detachNewThread { [self] in
                wait(for: expectations, timeout: timeout, enforceOrder: enforceOrder)
                continuation.resume()
            }
        }
    }
}
#endif

[grynspan]

For anyone watching at home: if you're developing for a Darwin-based platform (macOS, iOS, etc.) using the version of XCTest that ships with Xcode 14.3 or later, this API is already available and you don't need the category.