Module: ActiveSupport::Testing::Assertions

Defined in:
activesupport/lib/active_support/testing/assertions.rb

Instance Method Summary collapse

Instance Method Details

#assert_blank(object, message = nil) ⇒ Object

Test if an expression is blank. Passes if object.blank? is true.

assert_blank [] # => true


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# File 'activesupport/lib/active_support/testing/assertions.rb', line 83

def assert_blank(object, message=nil)
  message ||= "#{object.inspect} is not blank"
  assert object.blank?, message
end

#assert_difference(expression, difference = 1, message = nil, &block) ⇒ Object

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


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# 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) ⇒ Object

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


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# File 'activesupport/lib/active_support/testing/assertions.rb', line 76

def assert_no_difference(expression, message = nil, &block)
  assert_difference expression, 0, message, &block
end

#assert_present(object, message = nil) ⇒ Object

Test if an expression is not blank. Passes if object.present? is true.

assert_present {:data => 'x' } # => true


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# File 'activesupport/lib/active_support/testing/assertions.rb', line 91

def assert_present(object, message=nil)
  message ||= "#{object.inspect} is blank"
  assert object.present?, message
end