How do you write and execute Ruby tests in a Ruby interpreter?

Question

I was working with the lotrepls Ruby interpreter, and I want like to write tests in the interpreter that I can then write Ruby code to pass. In Python, I can write doctests and then write code to pass the doctests. For example:

>>> b  
1

This tests that b=1, and entering b=1 will get this doctest to pass.

Is there a similar way to write tests in a Ruby interpreter, execute them, write code to pass the tests, and then execute the test again? Is there a Ruby doctest equivalent? For my application, I will execute tests and code in a hosted interpreter like lotrepls rather than install something on my local machine.

Answer 1

There's RubyDocTest, but I'd encourage you to look at something like RSpec or another modern BDD/TDD framework.

It's pretty easy to write tests there too, and you get access to complex and/or custom assertions that you can't really get in a doctest. For instance, here's a simple set of tests for a baseball scoring app:

describe BaseballScorer do
  before :each do
    @s = Scorer.new(Game.new)
  end

  it "should score a 0-0 game when no runs are hit" do
    @s.home.score.should == @s.away.score.should == @s.total_runs
  end

  it "should record runs that are hit" do
    @s.game.run_hit(:away)
    @s.away.runs.should == @s.away.score.should == 1
  end

  # ...