MinitestToRspec

Converts minitest files to rspec.

• Selected assertions from Test::Unit, minitest, and ActiveSupport are converted to rspec-expectations.
• Selected methods from mocha are converted to rspec-mocks. (Experimental)

Example

Input:

require 'test_helper'
class ArrayTest < ActiveSupport::TestCase
  test "changes length" do
    ary = []
    assert_difference "ary.length" do
      ary.push(:x)
    end
  end
end

Output:

require("spec_helper")
RSpec.describe(Array) do
  it("changes length") do
    ary = []
    expect { ary.push(:x) }.to(change { ary.length })
  end
end

You might not like the code style of the output. More on that below.

Install

gem install minitest_to_rspec

Usage

CLI

mt2rspec [--rails] [--mocha] source_file [target_file]
mt2rspec --help

Ruby

require 'minitest_to_rspec'
converter = MinitestToRspec::Converter.new(rails: false, mocha: false)
converter.convert("assert('banana')")
#=> "expect(\"banana\").to(be_truthy)"

Output

The only goal is correctness. Code style is not a consideration. Providing the level of configuration necessary to make everyone happy would be a huge distraction from the main purpose.

After conversion, I recommend using rubocop's awesome --auto-correct feature to apply your preferred code style.

Comments are discarded by ruby_parser, so we have no way of preserving them.

Supported Assertions

Selected assertions from minitest, Test::Unit, and ActiveSupport. See doc/supported_assertions.md for rationale. Contributions are welcome.

Assertion	Arity	Source
assert
assert_difference	1,2
assert_equal	2,3	Test::Unit
assert_not_equal	2,3	Test::Unit
assert_match
assert_nil
assert_not_nil
assert_no_difference		ActiveSupport
assert_nothing_raised		Test::Unit
assert_raise	0..2	Test::Unit
assert_raises	0..2	Minitest
refute
refute_equal

Supported Mocha

Mocha	Arity	Block	Notes
any_instance	0	n/a
expects	1	n/a
once	0	n/a
stub	0,1,2	no
stub_everything	0,1,2	no	Uses as_null_object, not the same.
stubs	1	n/a
twice	0	n/a

To do: at_least, never, raises, etc.

Acknowledgements

This project would not be possible without ruby_parser, sexp_processor, and ruby2ruby by Ryan Davis.