Methods
A
Instance Public methods
assert_blank(object, message=nil)

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

assert_blank [] # => true

Source: show | on GitHub 

# 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)

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

Source: show | on GitHub 

# 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)

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

Source: show | on GitHub 

# 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)

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

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

Source: show | on GitHub 

# 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