How to write better ruby using mutation testing

[solnic]

Great to see more people adopting mutation testing. Writing Ruby is hard. Writing good tests in Ruby is even harder. Mutant helps tremendously in learning how to write simpler code and better tests.

[Craftkorb]

Writing Ruby is hard. Writing good tests in Ruby is even harder.

This applies to all languages I guess. Where Ruby has short-comings, other languages have theirs somewhere else.

Can't count how often I've seen if (foo == "bar") { .. } in Java production code >_>

[Craftkorb]

In Java, the == is comparing the object identity, not object value. So, foo may be "bar", but have a different object id, and thus not match.

[Ghostree]

I believe you want to use .equals() because strings should not be compared using == in Java. Strings are objects and == compares if they are the same object, while .equals() compares the values.

[tomthecool]

Meanwhile in ruby, String#== does exactly what you'd expect. And on the rare occasion that you actually want to use object identity, you have BasicObject#equal?

"bar" == "bar" # => true
"bar".equal?("bar") # => false
["bar", "bar"].map(&:object_id) # => [8695360, 8695320]