EarlGrey() has wrong line number for page objects

[bootstraponline]

In EarlGrey.swift, EarlGrey is defined as:

public func EarlGrey() -> EarlGreyImpl! {
  return EarlGreyImpl.invokedFromFile(#file, lineNumber: #line)
}

I define a login page object:

public class LoginPage {

    //# MARK: - Login Page Elements

    private var domainField: GREYElementInteraction {
        return EarlGrey().selectElementWithMatcher(grey_accessibilityID("domain_field"))
    }

which is then used:

func assertPageObjects() {
    domainField.assertWithMatcher(grey_sufficientlyVisible())
}

The line number is wrong because EarlGrey() sets it to be on the EarlGrey().selectElementWithMatcher... line.

I've had to update EarlGrey.swift like this:

//# MARK: - Custom EarlGrey file/line

extension EarlGreyImpl {
    // Use @nonobjc to fix A declaration cannot be both 'final' and 'dynamic' error
    @nonobjc public static var file: String = ""
    @nonobjc public static var line: UInt = 0

    public static func setFromFile(file: String, _ line: UInt) {
        self.file = file
        self.line = line
    }
}

public func grey_invokedFromFile(file: String, _ line: UInt) {
    EarlGreyImpl.setFromFile(file, line)
}

public func EarlGrey() -> EarlGreyImpl! {
  return EarlGreyImpl.invokedFromFile(EarlGreyImpl.file, lineNumber: EarlGreyImpl.line)
}

and update the page object:

func assertPageObjects(file: String = #file, _ line: UInt = #line) {
    grey_invokedFromFile(file, line)

    domainField.assertWithMatcher(grey_sufficientlyVisible())
}

now the line number is correctly identified in the test. Thoughts on how to best update EarlGrey.swift to handle this use case?

[khandpur]

This particular feature is about highlighting the EarlGrey invocation in the test code which led to the failure. This is an interesting use case and will fail the same way for the Objc version as well. Even though Objc can rely on macro expansion to include file and line# alongside the original method calls it would require us to define a macro for each top-level API and sub-APIs which can be called from those top-level APIs. Perhaps we need to rethink this.

[tirodkar]

This seems to be fixed by the above PR. @bootstraponline please close this or update it in case this is still present.

[bootstraponline]

// Use to report errors on the correct file/line
public func grey_invokedFromFile(_ file:StaticString, _ line:UInt) {
  EarlGreyImpl.invoked(fromFile: file.description, lineNumber: line)
}

I still have to use ^ throughout the code to get accurate file & line numbers. If that's the best we can do for Swift, then this issue is safe to close.

[tirodkar]

@bootstraponline sorry, but how does this affect your final API? Do you have to add grey_invokedFromFile to each file that you add? Are you still able to do EarlGrey.select(...) ?

[bootstraponline]

It looks like this using the page object pattern.

// swift 3
private static var loginButton: GREYElementInteraction {
  return EarlGrey.select(elementWithMatcher: grey_accessibilityID("login_button"))
}

static func tapLoginButton(_ file: StaticString = #file, _ line: UInt = #line) {
  grey_invokedFromFile(file, line)

  loginButton.perform(grey_tap())
}

func testLoginPage_loginSuccessful() {
  loginPage.tapLoginButton()
}