Sample tests for Ruby version of this kata are not provided :( Unfortunately, there are no example tests and you'd have to add them by yourself., for example like this:

describe "Solution" do
  it "should test for something" do
    Test.assert_equals(to_camel_case(""), "")
    Test.assert_equals(to_camel_case("the-stealth-warrior"), "theStealthWarrior")
    Test.assert_equals(to_camel_case("The_Stealth_Warrior"), "theStealthWarrior")
  end
end

However full test suite seems to run correctly, and I get values printed with this code:

def to_camel_case(str)
  print str
  ""
end

So if you get nothing printed on full attempt, you probably are doing something wrong.