module ActiveSupport::Testing::Assertions

def _assert_nothing_raised_or_warn(assertion, &block)

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

def assert_changes(expression, message = nil, from: UNTRACKED, to: UNTRACKED, &block)

end
post :create, params: { status: { incident: true } }
assert_changes -> { Status.all_good? }, 'Expected the status to be bad' do

An error message can be specified.

end
@object = :foo
assert_changes :@object, from: nil, to: :foo do

executed.
expected initial value and the expected value after the block was
The keyword arguments +:from+ and +:to+ can be given to specify the

end
@object = 42
assert_changes :@object do

anything that can be converted to string with #to_s.
The assertion is useful to test side effects. The passed block can be

end
post :create, params: { status: { ok: false } }
assert_changes -> { Status.all_good? } do

the block. A lambda can be passed for the block as well.
You can pass the block as a string to be evaluated in the context of

end
post :create, params: { status: { ok: false } }
assert_changes 'Status.all_good?' do

and after invoking the passed in block.
Assertion that the result of evaluating an expression is changed before
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}"
    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}\n"
    error = "#{message}.\n#{error}" if message
    assert to === after, error
  end
  retval
end

def assert_difference(expression, *args, &block)

end
post :delete, params: { id: ... }
assert_difference 'Article.count', -1, 'An Article should be destroyed' do

An error message can be specified.

end
post :create, params: { article: {...} }
assert_difference [->{ Article.count }, ->{ Post.count }], 2 do

end
post :create, params: { article: {...} }
assert_difference ->{ Article.count }, 2 do

A lambda or a list of lambdas can be passed in and evaluated:

end
post :create, params: { article: {...} }
assert_difference ->{ Article.count } => 1, ->{ Notification.count } => 2 do

A hash of expressions/numeric differences can also be passed in and evaluated.

end
post :create, params: { article: {...} }
assert_difference [ 'Article.count', 'Post.count' ], 2 do

An array of expressions can also be passed in and evaluated.

end
post :delete, params: { id: ... }
assert_difference 'Article.count', -1 do

The default is 1.
An arbitrary positive or negative difference can be specified.

end
post :create, params: { comment: {...} }
assert_difference 'Article.last.comments(:reload).size' do

An arbitrary expression is passed in and evaluated.

end
post :create, params: { article: {...} }
assert_difference 'Article.count' do

result of what is evaluated in the yielded block.
Test numeric difference between the return value of an expression as a
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|
    error  = "#{code.inspect} didn't change by #{diff}"
    error  = "#{message}.\n#{error}" if message
    assert_equal(before_value + diff, exp.call, error)
  end
  retval
end

def assert_no_changes(expression, message = nil, from: UNTRACKED, &block)

end
post :create, params: { status: { ok: false } }
assert_no_changes -> { Status.all_good? }, 'Expected the status to be good' do

An error message can be specified.

end
post :create, params: { status: { ok: true } }
assert_no_changes -> { Status.all_good? }, from: true do

initial value.
Provide the optional keyword argument :from to specify the expected

end
post :create, params: { status: { ok: true } }
assert_no_changes 'Status.all_good?' do

and after invoking the passed in block.
Assertion that the result of evaluating an expression is not changed before
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

def assert_no_difference(expression, message = nil, &block)

end
post :create, params: { article: invalid_attributes }
assert_no_difference [ 'Article.count', -> { Post.count } ] do

An array of expressions can also be passed in and evaluated.

end
post :create, params: { article: invalid_attributes }
assert_no_difference 'Article.count', 'An Article should not be created' do

An error message can be specified.

end
post :create, params: { article: invalid_attributes }
assert_no_difference -> { Article.count } do

A lambda can be passed in and evaluated.

end
post :create, params: { article: invalid_attributes }
assert_no_difference 'Article.count' do

changed before and after invoking the passed in block.
Assertion that the numeric result of evaluating an expression is not
def assert_no_difference(expression, message = nil, &block)
  assert_difference expression, 0, message, &block
end

def assert_not(object, message = nil)

assert_not foo, 'foo should be false'

An error message can be specified.

assert_not 'foo' # => Expected "foo" to be nil or false
assert_not false # => true
assert_not nil # => true

like if foo.
+nil+ or +false+. "Truthy" means "considered true in a conditional"
Asserts that an expression is not truthy. Passes if object is
def assert_not(object, message = nil)
  message ||= "Expected #{mu_pp(object)} to be nil or false"
  assert !object, message
end

def assert_nothing_raised

end
perform_service(param: 'no_exception')
assert_nothing_raised do

Passes if evaluated code in the yielded block raises no exception.

Assertion that the block should not raise an exception.
def assert_nothing_raised
  yield
rescue => error
  raise Minitest::UnexpectedError.new(error)
end