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
    # File activesupport/lib/active_support/testing/assertions.rb, line 83
83:       def assert_blank(object, message=nil)
84:         message ||= "#{object.inspect} is not blank"
85:         assert object.blank?, message
86:       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
    # 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
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 created" do
    post :create, :article => invalid_attributes
  end
    # File activesupport/lib/active_support/testing/assertions.rb, line 76
76:       def assert_no_difference(expression, message = nil, &block)
77:         assert_difference expression, 0, message, &block
78:       end
assert_present(object, message=nil)

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

  assert_present {:data => 'x' } # => true
    # File activesupport/lib/active_support/testing/assertions.rb, line 91
91:       def assert_present(object, message=nil)
92:         message ||= "#{object.inspect} is blank"
93:         assert object.present?, message
94:       end