instance method `assert_no_changes`

Ruby on Rails 5.2.8.1

Since v5.2.8.1

Available in: v5.2.8.1 v6.0.6 v6.1.7.10 v7.0.10 v7.1.6 v7.2.3 v8.0.4 v8.1.2

Compare with:

assert_no_changes(expression, message = nil, &block)

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

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

Parameters

expression req
message opt = nil
block block

Source

# File activesupport/lib/active_support/testing/assertions.rb, line 199
      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 before == after, error

        retval
      end

Defined in activesupport/lib/active_support/testing/assertions.rb line 199 · View on GitHub · Improve this page · Find usages on GitHub

Defined in ActiveSupport::Testing::Assertions

Signature

Parameters