The biggest user differences between Capybara 2.x and 3.x are the changes in behavior of `first` and `all`. In Capybara 2.x both methods would, by default, return immediately with nil if no matching elements exist on the page. In Capybara 3.x this has changed to include the waiting/retrying behavior found in the other Capybara finders and matchers.
`first` will now wait up to `Capybara.default_max_wait_time` seconds for at least one matching element to exist, and return the first matching element. If no matching elements are found within the time it will now raise a `Capybara::ElementNotFound` error instead of returning nil. If you need to maintain the previous behavior you can pass `minimum: 0` as an option to `first`
`all` will now wait up to `Capybara.default_max_wait_time` seconds for at least one matching element to exist, and return the matching elements. If no matching elements are found within the time it will return an empty result set. If you need to maintain the previous behavior you can pass `wait: false` as an option to `all`
`Node#text` no longer fully normalizes whitespace, instead returning text as close as possible to "as rendered". This means non-blanking spaces will no longer be collapsed, carriage returns may be returned in text strings, etc. This affects not only the `Node#text` method but also methods that take a `:text` option as well as the text related predicates, assertions, and matchers (`has_text?`, `has_content?`, `assert_text`, `have_text`, etc.).