Test::Rails Assertions

http://nubyonrails.com/articles/ruby-rails-test-rails-cheat-sheet
Standard Assertions

assert boolean
assert_equal expected, actual
assert_raise *args
assert_raises *args, &block
assert_instance_of klass, object
assert_nil object
assert_kind_of klass, object
assert_respond_to object, method
assert_match pattern, string
assert_same expected, actual
assert_operator object1, operator, object2
assert_nothing_raised *args
assert_not_same expected, actual
assert_not_equal expected, actual
assert_not_nil object
assert_no_match regexp, string
assert_throws expected_symbol, &proc
assert_nothing_thrown &proc
assert_in_delta expected_float, actual_float, delta
assert_send send_array
assert_assigned ivar, value = NOTHING
• deny_assigned
assert_content_type type, message = nil
assert_flash key, content
assert_image src
assert_error_on field, type
assert_field form_action, type, model, column, value = nil
assert_input form_action, type, name, value = nil
assert_label form_action, name, include_f = true
assert_links_to href, content = nil
• deny_links_to
assert_multipart_form form_action
assert_post_form form_action
assert_select form_action, model, column, options
assert_submit form_action, value
assert_tag_in_form form_action, options
• deny
assert_empty obj
• deny_empty
assert_includes obj, item, message = nil
• deny_includes
assert_response type
assert_redirected_to options = {}
assert_template expected
assert_recognizes expected_options, path, extras={}
assert_generates expected_path, options, defaults={},
extras = {}
assert_routing path, options, defaults={}, extras={}
assert_tag *opts
assert_no_tag *opts
assert_dom_equal expected, actual
assert_dom_not_equal expected, actual
assert_valid record

Rails Assertions
Most also take a message argument as the last parameter. The message will be shown if the test fails.