require 'active_support/core_ext/array/wrap'
require 'active_support/core_ext/object/blank'
module ActiveSupport
module Testing
module Assertions
# Test numeric difference between the return value of an expression as a result of what is evaluated
# in the yielded block.
#
# assert_difference 'Article.count' do
# post :create, :article => {...}
# end
#
# An arbitrary expression is passed in and evaluated.
#
# assert_difference 'assigns(:article).comments(:reload).size' do
# post :create, :comment => {...}
# end
#
# An arbitrary positive or negative difference can be specified. The default is +1.
#
# assert_difference 'Article.count', -1 do
# post :delete, :id => ...
# end
#
# An array of expressions can also be passed in and evaluated.
#
# assert_difference [ 'Article.count', 'Post.count' ], +2 do
# post :create, :article => {...}
# end
#
# A error message can be specified.
#
# assert_difference 'Article.count', -1, "An Article should be destroyed" do
# post :delete, :id => ...
# end
def assert_difference(expression, difference = 1, message = nil, &block)
b = block.send(:binding)
exps = Array.wrap(expression)
before = exps.map { |e| eval(e, b) }
yield
exps.each_with_index do |e, i|
error = "#{e.inspect} didn't change by #{difference}"
error = "#{message}.\n#{error}" if message
assert_equal(before[i] + difference, eval(e, b), error)
end
end
# Assertion that the numeric result of evaluating an expression is not changed before and after
# invoking the passed in block.
#
# assert_no_difference 'Article.count' do
# post :create, :article => invalid_attributes
# end
#
# A error message can be specified.
#
# assert_no_difference 'Article.count', "An Article should not be destroyed" do
# post :create, :article => invalid_attributes
# end
def assert_no_difference(expression, message = nil, &block)
assert_difference expression, 0, message, &block
end
# Test if an expression is blank. Passes if object.blank? is true.
#
# assert_blank [] # => true
def assert_blank(object)
assert object.blank?, "#{object.inspect} is not blank"
end
# Test if an expression is not blank. Passes if object.present? is true.
#
# assert_present {:data => 'x' } # => true
def assert_present(object)
assert object.present?, "#{object.inspect} is blank"
end
end
end
end
