Nimble Matchers for UIKit

This package provides a number of nimble matchers intended for verifying the state of UIKit components.

I strongly believe that unit tests should be written in a declarative manner, and while expect(label?.text).to(equal("some value")) works and is somewhat descriptive, it's not really declarative. I find expect(label).to(displayText("some value")) better conveys the intent behind the behavior being described.

Though, the real impetus that started me on this path of writing matchers is the beVisible matcher. The main ways to set a view as invisible are 1. set isHidden to true and 2. Remove it from the view hierarchy. When you're unit testing, you need to assert on the view that's actually hidden or removed (say, a container view), and you also have the test specifying the method used to make the view hidden from the user. beVisible combines both of those by verifying that an asserted-on UIView is within (or not) a given UIView hierarchy. There are also other ways of making a view invisible (which usually are the result of bugs) which this matcher attempts to check for.

Currently, this provides the following matchers:

• beAnAccessibilityElement verifies whether the NSObject being asserted on has isAccessibilityElement set.
• haveAccessibilityLabel verifies the contents of the NSObject's accessibilityLabel property.
• haveAccessibilityTraits verifies the contents of the NSObject's accessibilityTraits property.
• haveAccessibilityValue verifies the contents of the NSObject's accessibilityValue property.
• haveAccessibilityHint verifies the contents of the NSObject's accessibilityHint property.
• beEnabled verifies the contents of the UIControl's, UIAlertAction's, or UIBarButton's isEnabled property. This is done with an Enablable property that all three of those objects conform to.
• beVisible verifies whether a given UIView is visible inside of another UIView hierarchy - or is shown within a UIViewController. Being "visible" means that the asserted-on view is within the expected view hierarchy, and that none of the views involved have: isHidden set to true, alpha set to 0, frame.size.width set to 0, or frame.size.height set to 0. It does not check to see if the view is occluded by other views, nor other ways of hiding a view from the user.
• displayText verifiers whether a given UILabel, UITextField, UITextView or UIButton has their text (UILabel/UITextField/UITextView) set to the expected string value (using the TextDisplayer custom protocol) that UILabel, UITextField and UITextView conform to, or the UIButton's title(for:) method returns the expected string value for the given UIControl.State (defaulting to normal).
• displayPlaceholder verifies that the contents of the UITextField's placeholder property matches the given string value.
• haveImage verifies that the UIImageView or UIButton are displaying the given UIImage. This works on a pointer-level comparison, and nothing particularly "smart".
• haveKeyCommand verifies that the UIResponder's keyCommands property contains a UIKeyCommand matching the given properties.
• haveTextColor verifies that the UILabel, UITextField, UITextView or UIButton have their textColor (UILabel/UITextField/UITextView) set to the expected color (using the TextDisplayer custom protocol), or the UIButton's titleColor(for:) method returns the expected color for the given UIControl.State (defaulting to normal).
• haveTheDefaultPointerInteraction verifies that you did the bare minimum to give the UIView or UIButton the "default" pointer interaction. What this means for UIView is the interactions property contains 1 and only 1 UIPointerInteraction instance, and that UIPointerInteraction doesn't have a delegate. For UIButton, it means that you did not add any UIPointerInteractions, and instead you set the isPointerInteractionEnabled to true, and set pointerStyleProvider to nil.
• beOn verifies that the UISwitch's isOn property is set to true.
• beOff verifies that the UISwitch's isOn property is set to false.