Capybara

Visit a path visit '/blog' Navigates to a particular path. Pass a string or uses one of Rails path helpers.
Click on click_on 'Sign in' Clicks an anchor tag, button, or input with type submit. Pass a string containing the anchor text.

Page Interaction and Scoping

Has CSS? page.has_css?('nav[data-role=\"primary-navigation\"] li',text: 'FAQ') Returns a boolean value reporting whether a specific selector is present on this page.
Within within('footer'){expect(page).to have_content('Copyright')} Will scope interaction to within a particular selector. Useful if you're looking for content in a particular area.
Has content? page.has_content?('Sign in') Returns a boolean value reporting whether specific content is present on the page.
Find page.find('.todos li:first-child') Returns a single Capybara::Node::Element instance from the page.
All page.all('.todos li:nth-of_type(odd)') Returns an array of Capybara::Node::Element instance from the page.

Have CSS

expect(page).to have_css('header')
expect(page).to have_css('table#records + .pagination a[rel="next"')

Asserts that a certain selector is present on the page.

Have content

expect(page).to have_content('What are you looking for?')

Asserts that certain text is present on the page.

Current URL path comparison

expect(page).to have_current_path(prefix_path)

Click find('article a.title').click Triggers a click on a Capybara::Element. Works with JavaScript drivers.
Trigger find('input[name="post[title]"]').trigger('focus') Allows triggering of custom events. Works with JavaScript drivers.
Visible? find('.navigation').visible? Returns a boolean value reporting if the Capybara::Element is visible.

Fill in fill_in 'Title', with: 'I love Rails!' fill_in 'post[title]', with: 'I love Rails!' Fills in fields for you. Pass the label text or the name of the input.
Choose choose 'Male' Chooses a radio button. Pass the label text.
Check check 'I accept the terms of the site' Checks a checkbox. Pass the label text.
Uncheck uncheck 'Admin access?' Unchecks a checkbox. Pass the label text.
Select select 'MA', from: 'State' Selects an option from a select tag.
Attach file attach_file 'Image', 'path/to/image.jpg' Attaches a file.
Click button click_button 'Create My Account' Will press a button or `input[type='submit']`

Save and open page save_and_open_page Will save the current page (typically to `Rails.root/tmp`) and attemps to open the HTML in the default web browser.
Save and open screenshot save_and_open_screenshot Save a screenshot of the current page and open in the default image viewer.

Capybara automatically waits for asynchronous operations to complete. When you try to find an element that isn't on the page, it waits and retries until it is there, or a timeout duration elapses. The wait time is defined at `Capybara.default_max_wait_time`. Thanks to this gist and this presentation
Methods that wait `find(selector)`, `find_field`, `find_link` `within(selector)(scoping)` `has_selector?`, `has_no_selector?` & assertions form & link actions `click_link`, `click_button` `fill_in` `check/uncheck`, `select`, `choose`
Methods that don't wait `visit` `current_path` `all(selector)` `first(selector)` `execute_script` simple accessors: `text`, `value`, `title`, etc.