assert asserts that the block is truthy at the given time. The first parameter is an optional failure message.

assert 'login missing' do
  has_text? 'Login'
end

Check that example.com still has the same heading.

visit 'example.com'

assert 'somebody changed the text!'
  h1 = find 'h1'
  h1.text == 'Example Domain'
end

Asserts can also be written without the message.

assert do
  has_text? "Something"
end

Negative asserts can also be given.

assert do
  has_no_text? "Login"
end

# or
assert do
  !has_text? "Login"
end

• find