a = 1
b = 2
assert a == b # failure message says ‘expected true but was false’
assert_equal a, b # failure message says ‘expected 1 but was 2’

The second failure message is more informative.

  # To understand reality, we must compare our expectations against
  # reality.
  def test_assert_equality
    expected_value = 2
    actual_value = 1 + 1

    assert expected_value == actual_value
  end

  # Some ways of asserting equality are better than others.
  def test_a_better_way_of_asserting_equality
    expected_value = 2
    actual_value = 1 + 1

    assert_equal expected_value, actual_value
end

Why is it that assert_equal expected, actual is better than assert expected == actual? It seems that the latter is quite legible and arguably more readable.

The path to enlightenment (for ruby syntax at least): http://github.com/edgecase/ruby_koans/tree/master