Methods
Instance Public methods
Test if an expression is blank. Passes if object.blank? is true.
assert_blank [] # => true
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 lambda or a list of lambdas can be passed in and evaluated:
assert_difference lambda { Article.count }, 2 do post :create, :article => {...} end 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 activesupport/lib/active_support/testing/assertions.rb, line 47 47: def assert_difference(expression, difference = 1, message = nil, &block) 48: expressions = Array.wrap expression 49: 50: exps = expressions.map { |e| 51: e.respond_to?(:call) ? e : lambda { eval(e, block.binding) } 52: } 53: before = exps.map { |e| e.call } 54: 55: yield 56: 57: expressions.zip(exps).each_with_index do |(code, e), i| 58: error = "#{code.inspect} didn't change by #{difference}" 59: error = "#{message}.\n#{error}" if message 60: assert_equal(before[i] + difference, e.call, error) 61: end 62: 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 created" do post :create, :article => invalid_attributes end
Test if an expression is not blank. Passes if object.present? is true.
assert_present {:data => 'x' } # => true