Methods
Public Instance methods
assert_blank(object)

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

  assert_blank [] # => true

[ show source ]

    # File activesupport/lib/active_support/testing/assertions.rb, line 67
67:       def assert_blank(object)
68:         assert object.blank?, "#{object.inspect} is not blank"
69:       end
assert_difference(expression, difference = 1, message = nil) {|| ...}

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 error message can be specified. 

  assert_difference 'Article.count', -1, "An Article should be destroyed" do
    post :delete, :id => ...
  end

[ show source ]

    # File activesupport/lib/active_support/testing/assertions.rb, line 34
34:       def assert_difference(expression, difference = 1, message = nil, &block)
35:         b = block.send(:binding)
36:         exps = Array.wrap(expression)
37:         before = exps.map { |e| eval(e, b) }
38: 
39:         yield
40: 
41:         exps.each_with_index do |e, i|
42:           error = "#{e.inspect} didn't change by #{difference}"
43:           error = "#{message}.\n#{error}" if message
44:           assert_equal(before[i] + difference, eval(e, b), error)
45:         end
46:       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

[ show source ]

    # File activesupport/lib/active_support/testing/assertions.rb, line 60
60:       def assert_no_difference(expression, message = nil, &block)
61:         assert_difference expression, 0, message, &block
62:       end
assert_present(object)

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

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

[ show source ]

    # File activesupport/lib/active_support/testing/assertions.rb, line 74
74:       def assert_present(object)
75:         assert object.present?, "#{object.inspect} is blank"
76:       end