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rails--rails/activesupport/lib/active_support/testing/assertions.rb
2014-11-29 11:53:24 +01:00

97 lines
3.2 KiB
Ruby

require 'active_support/core_ext/object/blank'
module ActiveSupport
module Testing
module Assertions
# Assert that an expression is not truthy. Passes if <tt>object</tt> is
# +nil+ or +false+. "Truthy" means "considered true in a conditional"
# like <tt>if foo</tt>.
#
# assert_not nil # => true
# assert_not false # => true
# assert_not 'foo' # => Expected "foo" to be nil or false
#
# An error message can be specified.
#
# assert_not foo, 'foo should be false'
def assert_not(object, message = nil)
message ||= "Expected #{mu_pp(object)} to be nil or false"
assert !object, message
end
# 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 <tt>1</tt>.
#
# 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 ->{ Article.count }, 2 do
# post :create, article: {...}
# end
#
# assert_difference [->{ Article.count }, ->{ Post.count }], 2 do
# post :create, article: {...}
# end
#
# An error message can be specified.
#
# assert_difference 'Article.count', -1, 'An Article should be destroyed' do
# post :delete, id: ...
# end
def assert_difference(expression, difference = 1, message = nil, &block)
expressions = Array(expression)
exps = expressions.map { |e|
e.respond_to?(:call) ? e : lambda { eval(e, block.binding) }
}
before = exps.map(&: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
# 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
#
# An error message can be specified.
#
# assert_no_difference 'Article.count', 'An Article should not be created' do
# post :create, article: invalid_attributes
# end
def assert_no_difference(expression, message = nil, &block)
assert_difference expression, 0, message, &block
end
end
end
end