I misread your message, I thought you said the contrary. I raised an issue for similar reasons with PHP, I'll add Java to it.

That's what the kata asks to do.

Duplicate suggestion below

Maybe you use "grEy" but not "grAy" in your map?

It can be nil if you calling function without do-catch. For instance: var node = try? getNth(node, index)

Fixed

I don't think \r should be removed because the description says:

The return value of your interpreter should be a representation of the final state of the 2D data grid where each row is separated from the next by a CRLF (\r\n).

Is this something specific to Swift? If so, please open a new issue describing it.

Depends on the language. In Ruby or Python it's quite easy if you know what to do.

For Swift, there is a example test XCTAssertEqual(boolfuck(";"), String(bytes: [0x01], encoding: .isoLatin1)!). The code only outputs the bit in the default position, and yet the test says it should be 1. In the next test, printing Hello, world!\n, the code for the first part is ;;;+;+;;+;+;, which is 00010010. This clearly shows that the default data bits in the cell are 0, so the first test should print the character with value 0 not the character with value 0x01.

Agreed. On the other hand some 7kyu-s Katas feel more difficult than this one.
It would be better if we could give a kyu level after completion.
That way Katas would have a better leveling.

Damn. CodeWars needs to do something about these broken tests. Makes me so frustrated I want to stop coming here.

Test cases for Swift need to be more robust.

There is no specification about the shift parameter, and the only restriction is that it should be an Int type. If such is the case, test cases should check for cases where the shift is > 26, < 0, and check whether it is still working fine. Either that or the description/API should reflect this.

Also, some solutions for Swift will break if the input were to be encode("zzzz", 2) which is a valid input

Okay. I found the reason. Remove all \rs (carriage return) from the test cases and they should work fine. Someone please fix this.

Test for Swift prints Process exited prematurely with a SIGILL signal. in the log, even when the code just returns an empty string.

Damn!! This was reported 6 months ago!! Someone, please.