---
title: "XCTUnwrap(_:_:file:line:)"
framework: xctest
role: symbol
role_heading: Function
path: "xctest/xctunwrap(_:_:file:line:)"
---

# XCTUnwrap(_:_:file:line:)

Asserts that an expression is not nil, and returns the unwrapped value.

## Declaration

```swift
func XCTUnwrap<T>(_ 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

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

Discussion This function generates a failure when expression is nil. Otherwise, it returns the unwrapped value of expression for subsequent use in the test.

## See Also

### Tests for a Non-Nil Condition

- [XCTAssertNotNil(_:_:file:line:)](xctest/xctassertnotnil(_:_:file:line:).md)