Unit testing

Good karma for Ruby and for Extreme Programming today. I've just tried to port libgmp-ruby from handmade testing system to Test::Unit. It is totally sweet:

#!/usr/bin/ruby

require 'test/unit'
require 'gmp'

class TC_Z < Test::Unit::TestCase
   def test_init_null
       assert_equal(GMP::Z.new(), 0, "GMP::Z.new() should initialize to 0")
   end

   def test_init_fixnum
       assert_equal(GMP::Z.new(1), 1, "GMP::Z.new(x : Fixnum) should initialize to x")
   end

   def test_init_z
       b = GMP::Z.new(1)
       assert_equal(GMP::Z.new(b), b, "GMP::Z.new(x : GMP::Z) should initialize to x")
   end

   def test_init_string
       assert_equal(GMP::Z.new("1"), 1, "GMP::Z.new(x : String) should initialize to x")
   end

   def test_init_bignum
       assert_equal(GMP::Z.new(2**32), 2**32, "GMP::Z.new(x : Bignum) should initialize to x")
   end
end

Executing this script runs all the tests:

$ ./unit_tests_1.rb
Loaded suite ./unit_tests_1
Started
.....
Finished in 0.006574 seconds.

5 tests, 5 assertions, 0 failures, 0 errors

Do you see any executable code, any list of tests to run ? Nah, it works by smoke and mirrors. We're going to leave XML BDSM to Java programmers, they seem to like it. ;-) It even found an actual bug in libgmp-ruby (something was pointing the wrong way around) in the first 5 minutes of testing. That's kinda cool. You can use multiple assertions per test, fixtures and so on. It still works by magic.

class TC_Q_Basic < Test::Unit::TestCase
   def setup
       @a=GMP::Q.new(100,11)
       @b=GMP::Q.new(200,17)
       @c=GMP::Z.new(40)
       @d=2**32
   end

   def test_add
       assert_equal(@a + @b, GMP::Q(3900, 187),       "GMP::Q should add GMP::Q correctly")
       assert_equal(@a + @c, GMP::Q(540,  11),        "GMP::Q should add GMP::Z correctly")
       assert_equal(@c + @a, GMP::Q(540,  11),        "GMP::Z should add GMP::Q correctly")
       assert_equal(@a +  2, GMP::Q(122,  11),        "GMP::Z should add Fixnum correctly")
       assert_equal(@a + @d, GMP::Q(47244640356, 11), "GMP::Z should add Bignum correctly")
       assert_equal( 2 + @a, GMP::Q(122,  11),        "Fixnum should add GMP::Q correctly")
       assert_equal(@d + @a, GMP::Q(47244640356, 11), "Bignum should add GMP::Q correctly")
   end
end