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Is there a matcher that simultaneously asserts the type of an object and casts it? #923
Description
- I have read CONTRIBUTING and have done my best to follow them.
I'm trying to make an assertion about the type of an error, and of a field on it. This requires me to cast.
This was my work-around:
expect(try somethingThatThrows()).to(throwError { error in
expect(error).to(beAnInstanceOf(MyCustomError))
expect((error as! MyCustomError).cause) == POSIXError(.ENOMEM)
}Notice how I needed to force cast from Error to MyCustomError in order to gain access to the cause property. This force-cast shouldn't ever fail (because of the typecheck on the previous line), but it's still a little crufty.
Is there a build in matcher that can help with this?
Here are some other alternatives I considered:
expect(try somethingThatThrows()).to(throwError { error in
if let error = error as? MyCustomError {
expect(error.cause) == POSIXError(.ENOMEM)
} else {
fail()
}expect(try somethingThatThrows()).to(throwError { error in
expect((error as? MyCustomError).cause) == POSIXError(.ENOMEM)
}Environment
List the software versions you're using:
- Quick: 4.0.0
- Nimble: 9.2.0
- Xcode Version: 13.0 (13A5201i)
- Swift Version: 5.5
Please also mention which package manager you used and its version. Delete the
other package managers in this list:
- Swift Package Manager 5.5.0
Activity
[-]Is there a matcher that simultaneously asserts the type of an object and casts?[/-][+]Is there a matcher that simultaneously asserts the type of an object and casts it?[/+]ikesyo commentedon Aug 28, 2021
Nimble/Sources/Nimble/Matchers/ThrowError.swift
Lines 138 to 141 in 2c44aee
Nimble/Tests/NimbleTests/Matchers/ThrowErrorTest.swift
Lines 55 to 59 in 2c44aee
I think this overload is what you want.