module ActiveSupport module Testing module Assertions UNTRACKED = Object.new # :nodoc: # Asserts that an expression is not truthy. Passes if object is # +nil+ or +false+. "Truthy" means "considered true in a conditional" # like if foo. # # 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 # Assertion that the block should not raise an exception. # # Passes if evaluated code in the yielded block raises no exception. # # assert_nothing_raised do # perform_service(param: 'no_exception') # end def assert_nothing_raised yield 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, params: { article: {...} } # end # # An arbitrary expression is passed in and evaluated. # # assert_difference 'Article.last.comments(:reload).size' do # post :create, params: { comment: {...} } # end # # An arbitrary positive or negative difference can be specified. # The default is 1. # # assert_difference 'Article.count', -1 do # post :delete, params: { id: ... } # end # # An array of expressions can also be passed in and evaluated. # # assert_difference [ 'Article.count', 'Post.count' ], 2 do # post :create, params: { article: {...} } # end # # A lambda or a list of lambdas can be passed in and evaluated: # # assert_difference ->{ Article.count }, 2 do # post :create, params: { article: {...} } # end # # assert_difference [->{ Article.count }, ->{ Post.count }], 2 do # post :create, params: { article: {...} } # end # # An error message can be specified. # # assert_difference 'Article.count', -1, 'An Article should be destroyed' do # post :delete, params: { 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) retval = 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 retval 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, params: { article: invalid_attributes } # end # # An error message can be specified. # # assert_no_difference 'Article.count', 'An Article should not be created' do # post :create, params: { article: invalid_attributes } # end def assert_no_difference(expression, message = nil, &block) assert_difference expression, 0, message, &block end # Assertion that the result of evaluating an expression is changed before # and after invoking the passed in block. # # assert_changes 'Status.all_good?' do # post :create, params: { status: { ok: false } } # end # # You can pass the block as a string to be evaluated in the context of # the block. A lambda can be passed for the block as well. # # assert_changes -> { Status.all_good? } do # post :create, params: { status: { ok: false } } # end # # The assertion is useful to test side effects. The passed block can be # anything that can be converted to string with #to_s. # # assert_changes :@object do # @object = 42 # end # # The keyword arguments :from and :to can be given to specify the # expected initial value and the expected value after the block was # executed. # # assert_changes :@object, from: nil, to: :foo do # @object = :foo # end # # An error message can be specified. # # assert_changes -> { Status.all_good? }, 'Expected the status to be bad' do # post :create, params: { status: { incident: true } } # end def assert_changes(expression, message = nil, from: UNTRACKED, to: UNTRACKED, &block) exp = expression.respond_to?(:call) ? expression : -> { eval(expression.to_s, block.binding) } before = exp.call retval = yield unless from == UNTRACKED error = "#{expression.inspect} isn't #{from.inspect}" error = "#{message}.\n#{error}" if message assert from === before, error end after = exp.call if to == UNTRACKED error = "#{expression.inspect} didn't changed" error = "#{message}.\n#{error}" if message assert_not_equal before, after, error else error = "#{expression.inspect} didn't change to #{to}" error = "#{message}.\n#{error}" if message assert to === after, error end retval end # Assertion that the result of evaluating an expression is changed before # and after invoking the passed in block. # # assert_no_changes 'Status.all_good?' do # post :create, params: { status: { ok: true } } # end # # An error message can be specified. # # assert_no_changes -> { Status.all_good? }, 'Expected the status to be good' do # post :create, params: { status: { ok: false } } # end def assert_no_changes(expression, message = nil, &block) exp = expression.respond_to?(:call) ? expression : -> { eval(expression.to_s, block.binding) } before = exp.call retval = yield after = exp.call error = "#{expression.inspect} did change to #{after}" error = "#{message}.\n#{error}" if message assert_equal before, after, error retval end end end end