activesupport/lib/active_support/testing/assertions.rb
# frozen_string_literal: true
require "active_support/core_ext/enumerable"
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 <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
# Asserts that a block raises one of +exp+. This is an enhancement of the
# standard Minitest assertion method with the ability to test error
# messages.
#
# assert_raises(ArgumentError, match: /incorrect param/i) do
# perform_service(param: 'exception')
# end
#
def assert_raises(*exp, match: nil, &block)
error = super(*exp, &block)
assert_match(match, error.message) if match
error
end
alias :assert_raise :assert_raises
# 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.tap { assert(true) }
rescue => error
raise Minitest::UnexpectedError.new(error)
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 hash of expressions/numeric differences can also be passed in and evaluated.
#
# assert_difference ->{ Article.count } => 1, ->{ Notification.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, *args, &block)
expressions =
if expression.is_a?(Hash)
message = args[0]
expression
else
difference = args[0] || 1
message = args[1]
Array(expression).index_with(difference)
end
exps = expressions.keys.map { |e|
e.respond_to?(:call) ? e : lambda { eval(e, block.binding) }
}
before = exps.map(&:call)
retval = _assert_nothing_raised_or_warn("assert_difference", &block)
expressions.zip(exps, before) do |(code, diff), exp, before_value|
actual = exp.call
error = "#{code.inspect} didn't change by #{diff}, but by #{actual - before_value}"
error = "#{message}.\n#{error}" if message
assert_equal(before_value + diff, actual, 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
#
# A lambda can be passed in and evaluated.
#
# 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
#
# An array of expressions can also be passed in and evaluated.
#
# assert_no_difference [ 'Article.count', -> { Post.count } ] 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 = _assert_nothing_raised_or_warn("assert_changes", &block)
unless from == UNTRACKED
error = "Expected change from #{from.inspect}, got #{before.inspect}"
error = "#{message}.\n#{error}" if message
assert from === before, error
end
after = exp.call
error = "#{expression.inspect} didn't change"
error = "#{error}. It was already #{to.inspect}" if before == to
error = "#{message}.\n#{error}" if message
refute_equal before, after, error
unless to == UNTRACKED
error = "Expected change to #{to.inspect}, got #{after.inspect}\n"
error = "#{message}.\n#{error}" if message
assert to === after, error
end
retval
end
# Assertion that the result of evaluating an expression is not changed before
# and after invoking the passed in block.
#
# assert_no_changes 'Status.all_good?' do
# post :create, params: { status: { ok: true } }
# end
#
# Provide the optional keyword argument +:from+ to specify the expected
# initial value.
#
# assert_no_changes -> { Status.all_good? }, from: true 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, from: UNTRACKED, &block)
exp = expression.respond_to?(:call) ? expression : -> { eval(expression.to_s, block.binding) }
before = exp.call
retval = _assert_nothing_raised_or_warn("assert_no_changes", &block)
unless from == UNTRACKED
error = "Expected initial value of #{from.inspect}, got #{before.inspect}"
error = "#{message}.\n#{error}" if message
assert from === before, error
end
after = exp.call
error = "#{expression.inspect} changed"
error = "#{message}.\n#{error}" if message
if before.nil?
assert_nil after, error
else
assert_equal before, after, error
end
retval
end
private
def _assert_nothing_raised_or_warn(assertion, &block)
assert_nothing_raised(&block)
rescue Minitest::UnexpectedError => e
if tagged_logger && tagged_logger.warn?
warning = <<~MSG
#{self.class} - #{name}: #{e.error.class} raised.
If you expected this exception, use `assert_raises` as near to the code that raises as possible.
Other block based assertions (e.g. `#{assertion}`) can be used, as long as `assert_raises` is inside their block.
MSG
tagged_logger.warn warning
end
raise
end
end
end
end