- A
Instance Public methods
assert_changes(expression, message = nil, from: UNTRACKED, to: UNTRACKED, &block) Link
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
# File activesupport/lib/active_support/testing/assertions.rb, line 191 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}" 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}" if before == to error = "#{message}.\n#{error}" if message refute_equal before, after, error unless to == UNTRACKED error = "Expected change to #{to}, got #{after}\n" error = "#{message}.\n#{error}" if message assert to === after, error end retval end
assert_difference(expression, *args, &block) Link
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
# File activesupport/lib/active_support/testing/assertions.rb, line 101 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
assert_no_changes(expression, message = nil, from: UNTRACKED, &block) Link
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
# File activesupport/lib/active_support/testing/assertions.rb, line 238 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}" 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
assert_no_difference(expression, message = nil, &block) Link
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
assert_not(object, message = nil) Link
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'
assert_nothing_raised() Link
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
assert_raises(*exp, match: nil, &block) Link
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