Module | Test::Unit::Assertions |
In: |
vendor/rails/activesupport/lib/active_support/testing/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/testing/core_ext/test/unit/assertions.rb, line 38 38: def assert_difference(expressions, difference = 1, message = nil, &block) 39: expression_evaluations = Array(expressions).map do |expression| 40: [expression, lambda do 41: eval(expression, block.__send__(:binding)) 42: end] 43: end 44: 45: original_values = expression_evaluations.inject([]) { |memo, expression| memo << expression[1].call } 46: yield 47: expression_evaluations.each_with_index do |expression, i| 48: full_message = "" 49: full_message << "#{message}.\n" if message 50: full_message << "<#{expression[0]}> was the expression that failed" 51: assert_equal original_values[i] + difference, expression[1].call, full_message 52: end 53: 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/testing/core_ext/test/unit/assertions.rb, line 67 67: def assert_no_difference(expressions, message = nil, &block) 68: assert_difference expressions, 0, message, &block 69: end