Module | Test::Unit::Assertions |
In: |
vendor/rails/activesupport/lib/active_support/core_ext/test/unit/assertions.rb
|
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
# File vendor/rails/activesupport/lib/active_support/core_ext/test/unit/assertions.rb, line 37 37: def assert_difference(expressions, difference = 1, message = nil, &block) 38: expression_evaluations = Array(expressions).collect{ |expression| lambda { eval(expression, block.send!(:binding)) } } 39: 40: original_values = expression_evaluations.inject([]) { |memo, expression| memo << expression.call } 41: yield 42: expression_evaluations.each_with_index do |expression, i| 43: assert_equal original_values[i] + difference, expression.call, message 44: end 45: 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
# File vendor/rails/activesupport/lib/active_support/core_ext/test/unit/assertions.rb, line 59 59: def assert_no_difference(expressions, message = nil, &block) 60: assert_difference expressions, 0, message, &block 61: end