# XCTUnwrap(_:_:file:line:) Asserts that an expression is not `nil,` and returns the unwrapped value. ``` func XCTUnwrap(_ expression: @autoclosure () throws -> T?, _ message: @autoclosure () -> String = "", file: StaticString = #filePath, line: UInt = #line) throws -> T ``` ## Parameters `expression` An expression of type `T?`. The expression’s type determines the type of the return value. `message` An optional description of a failure. `file` The file where the failure occurs. The default is the filename of the test case where you call this function. `line` The line number where the failure occurs. The default is the line number where you call this function. ## Return Value The result of evaluating and unwrapping the `expression`, which is of type `T`. `XCTUnwrap()` only returns a value if `expression` is not `nil`. ## Discussion This function generates a failure when `expression` is `nil`. Otherwise, it returns the unwrapped value of `expression` for subsequent use in the test. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)