Methods
Instance Public methods
assert_blank(object, message=nil)
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Test if an expression is blank. Passes if object.blank? is true.
assert_blank [] # => true
assert_difference(expression, difference = 1, message = nil, &block)
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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 def assert_difference(expression, difference = 1, message = nil, &block) expressions = Array.wrap expression exps = expressions.map { |e| e.respond_to?(:call) ? e : lambda { eval(e, block.binding) } } before = exps.map { |e| e.call } yield expressions.zip(exps).each_with_index do |(code, e), i| error = "#{code.inspect} didn't change by #{difference}" error = "#{message}.\n#{error}" if message assert_equal(before[i] + difference, e.call, error) end end
assert_no_difference(expression, message = nil, &block)
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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