Ampersand isn't even needed :)

Definitely not a best practice. Ruby's built-in min_by method is written in C, and is thus faster. Also, this modifies the original array, which is a horrible practice.

What! I had no idea it was possible to unfreeze the test class....

That is one very long line of code.

Some more tags would be useful. Fun kata :)

Now, what takes longer: getting the maximum value from an array, or using a ternary?

I feel that this is almost too easy with the documentation given.... Maybe that's just me. Good introductory kata, though.

I guess using this calculator you could simply inject random code in, so it's not a "best practice," but it's certainly effective.
Example of 12-year-old troll breaking your calculator, and its machine: Calculator.new.evaluate(system("rm -rf *"))

Definitely not best practices...

It looks like you're returning a method instead of a number. Maybe ensure you're returning a number?

I'm doing this in Ruby. Running this locally seems to work (returns array of the two fittest binary integers). The problem is that, on Codewars, I get the error:

`inspect': wrong number of arguments (1 for 0) (ArgumentError)
	from `block (2 levels) in 
'
  from  `times'
    from  `block in   
'
	from  `block in describe'
  from  `measure'
  from  `describe'
	from  `describe'
	from  `
'.

This is annoying. It seems to be an error in the test, unless I'm somehow passing a variable to #inspect within the test.

You need to use a more efficient algorithm, or your program could be getting stuck in an infinite loop somewhere.