Difference
Better way to identify what's different between 2 instances.
Have you ever written tests?
Usually they use equality asserts, e.g. XCTAssertEqual
, what happens if the objects aren't equal? Xcode throws a wall of text at you:
This forces you to manually scan the text and try to figure out exactly whats wrong, what if instead you could just learn which property is different?
Installation
CocoaPods
Add pod 'Difference'
to your Podfile.
Carthage
Add github "krzysztofzablocki/Difference"
to your Cartfile.
SwiftPM
Add .package(name: "Difference", url: "https://github.com/krzysztofzablocki/Difference.git", .branch("master")),
dependency in your Package manifest.
Using lldb
Just write the following to see the difference between 2 instances:
po dumpDiff(expected, received)
Integrate with XCTest
Just add this to your test target:
public func XCTAssertEqual<T: Equatable>(_ expected: T, _ received: T, file: StaticString = #file, line: UInt = #line) {
XCTAssertTrue(expected == received, "Found difference for \n" + diff(expected, received).joined(separator: ", "), file: file, line: line)
}
Replace #file
with #filePath
if you're using Xcode 12+.
Integrate with Quick
Just add this to your test target:
public func equalDiff<T: Equatable>(_ expectedValue: T?) -> Predicate<T> {
return Predicate.define { actualExpression in
let receivedValue = try actualExpression.evaluate()
if receivedValue == nil {
var message = ExpectationMessage.fail("")
if let expectedValue = expectedValue {
message = ExpectationMessage.expectedCustomValueTo("equal <\(expectedValue)>", "nil")
}
return PredicateResult(status: .fail, message: message)
}
if expectedValue == nil {
return PredicateResult(status: .fail, message: ExpectationMessage.fail("").appendedBeNilHint())
}
return PredicateResult(bool: receivedValue == expectedValue, message: ExpectationMessage.fail("Found difference for " + diff(expectedValue, receivedValue).joined(separator: ", ")))
}
}