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Diffstat (limited to 'testing/marionette/client/docs/advanced')
-rw-r--r-- | testing/marionette/client/docs/advanced/actions.rst | 46 | ||||
-rw-r--r-- | testing/marionette/client/docs/advanced/debug.rst | 54 | ||||
-rw-r--r-- | testing/marionette/client/docs/advanced/findelement.rst | 126 | ||||
-rw-r--r-- | testing/marionette/client/docs/advanced/landing.rst | 13 | ||||
-rw-r--r-- | testing/marionette/client/docs/advanced/stale.rst | 71 |
5 files changed, 310 insertions, 0 deletions
diff --git a/testing/marionette/client/docs/advanced/actions.rst b/testing/marionette/client/docs/advanced/actions.rst new file mode 100644 index 000000000..294855a6f --- /dev/null +++ b/testing/marionette/client/docs/advanced/actions.rst @@ -0,0 +1,46 @@ +Actions +======= + +.. py:currentmodule:: marionette + +Action Sequences +---------------- + +:class:`Actions` are designed as a way to simulate user input as closely as possible +on a touch device like a smart phone. A common operation is to tap the screen +and drag your finger to another part of the screen and lift it off. + +This can be simulated using an Action:: + + from marionette import Actions + + start_element = marionette.find_element('id', 'start') + end_element = marionette.find_element('id', 'end') + + action = Actions(marionette) + action.press(start_element).wait(1).move(end_element).release() + action.perform() + +This will simulate pressing an element, waiting for one second, moving the +finger over to another element and then lifting the finger off the screen. The +wait is optional in this case, but can be useful for simulating delays typical +to a users behaviour. + +Multi-Action Sequences +---------------------- + +Sometimes it may be necessary to simulate multiple actions at the same time. +For example a user may be dragging one finger while tapping another. This is +where :class:`MultiActions` come in. MultiActions are simply a way of combining +two or more actions together and performing them all at the same time:: + + action1 = Actions(marionette) + action1.press(start_element).move(end_element).release() + + action2 = Actions(marionette) + action2.press(another_element).wait(1).release() + + multi = MultiActions(marionette) + multi.add(action1) + multi.add(action2) + multi.perform() diff --git a/testing/marionette/client/docs/advanced/debug.rst b/testing/marionette/client/docs/advanced/debug.rst new file mode 100644 index 000000000..e72d2549b --- /dev/null +++ b/testing/marionette/client/docs/advanced/debug.rst @@ -0,0 +1,54 @@ +Debugging +========= + +.. py:currentmodule:: marionette + +Sometimes when working with Marionette you'll run into unexpected behaviour and +need to do some debugging. This page outlines some of the Marionette methods +that can be useful to you. + +Please note that the best tools for debugging are the `ones that ship with +Gecko`_. This page doesn't describe how to use those with Marionette. Also see +a related topic about `using the debugger with Marionette`_ on MDN. + +.. _ones that ship with Gecko: https://developer.mozilla.org/en-US/docs/Tools +.. _using the debugger with Marionette: https://developer.mozilla.org/en-US/docs/Marionette/Debugging + + +Storing Logs on the Server +~~~~~~~~~~~~~~~~~~~~~~~~~~ + +By calling `~Marionette.log` it is possible to store a message on the server. +Logs can later be retrieved using `~Marionette.get_logs`. For example:: + + try: + marionette.log("Sending a click event") # logged at INFO level + elem.click() + except: + marionette.log("Something went wrong!", "ERROR") + + print(marionette.get_logs()) + +Disclaimer: Example for illustrative purposes only, don't actually hide +tracebacks like that! + + +Seeing What's on the Page +~~~~~~~~~~~~~~~~~~~~~~~~~ + +Sometimes it's difficult to tell what is actually on the page that is being +manipulated. Either because it happens too fast, the window isn't big enough or +you are manipulating a remote server! There are two methods that can help you +out. The first is `~Marionette.screenshot`:: + + marionette.screenshot() # takes screenshot of entire frame + elem = marionette.find_element(By.ID, 'some-div') + marionette.screenshot(elem) # takes a screenshot of only the given element + +Sometimes you just want to see the DOM layout. You can do this with the +`~Marionette.page_source` property. Note that the page source depends on the +context you are in:: + + print(marionette.page_source) + marionette.set_context('chrome') + print(marionette.page_source) diff --git a/testing/marionette/client/docs/advanced/findelement.rst b/testing/marionette/client/docs/advanced/findelement.rst new file mode 100644 index 000000000..abcbc8e89 --- /dev/null +++ b/testing/marionette/client/docs/advanced/findelement.rst @@ -0,0 +1,126 @@ +Finding Elements +================ +.. py:currentmodule:: marionette + +One of the most common and yet often most difficult tasks in Marionette is +finding a DOM element on a webpage or in the chrome UI. Marionette provides +several different search strategies to use when finding elements. All search +strategies work with both :func:`~Marionette.find_element` and +:func:`~Marionette.find_elements`, though some strategies are not implemented +in chrome scope. + +In the event that more than one element is matched by the query, +:func:`~Marionette.find_element` will only return the first element found. In +the event that no elements are matched by the query, +:func:`~Marionette.find_element` will raise `NoSuchElementException` while +:func:`~Marionette.find_elements` will return an empty list. + +Search Strategies +----------------- + +Search strategies are defined in the :class:`By` class:: + + from marionette import By + print(By.ID) + +The strategies are: + +* `id` - The easiest way to find an element is to refer to its id directly:: + + container = client.find_element(By.ID, 'container') + +* `class name` - To find elements belonging to a certain class, use `class name`:: + + buttons = client.find_elements(By.CLASS_NAME, 'button') + +* `css selector` - It's also possible to find elements using a `css selector`_:: + + container_buttons = client.find_elements(By.CSS_SELECTOR, '#container .buttons') + +* `name` - Find elements by their name attribute (not implemented in chrome + scope):: + + form = client.find_element(By.NAME, 'signup') + +* `tag name` - To find all the elements with a given tag, use `tag name`:: + + paragraphs = client.find_elements(By.TAG_NAME, 'p') + +* `link text` - A convenience strategy for finding link elements by their + innerHTML (not implemented in chrome scope):: + + link = client.find_element(By.LINK_TEXT, 'Click me!') + +* `partial link text` - Same as `link text` except substrings of the innerHTML + are matched (not implemented in chrome scope):: + + link = client.find_element(By.PARTIAL_LINK_TEXT, 'Clic') + +* `xpath` - Find elements using an xpath_ query:: + + elem = client.find_element(By.XPATH, './/*[@id="foobar"') + +.. _css selector: https://developer.mozilla.org/en-US/docs/Web/Guide/CSS/Getting_Started/Selectors +.. _xpath: https://developer.mozilla.org/en-US/docs/Web/XPath + + + +Chaining Searches +----------------- + +In addition to the methods on the Marionette object, HTMLElement objects also +provide :func:`~HTMLElement.find_element` and :func:`~HTMLElement.find_elements` +methods. The difference is that only child nodes of the element will be searched. +Consider the following html snippet:: + + <div id="content"> + <span id="main"></span> + </div> + <div id="footer"></div> + +Doing the following will work:: + + client.find_element(By.ID, 'container').find_element(By.ID, 'main') + +But this will raise a `NoSuchElementException`:: + + client.find_element(By.ID, 'container').find_element(By.ID, 'footer') + + +Finding Anonymous Nodes +----------------------- + +When working in chrome scope, for example manipulating the Firefox user +interface, you may run into something called an anonymous node. + +Firefox uses a markup language called XUL_ for its interface. XUL is similar +to HTML in that it has a DOM and tags that render controls on the display. One +ability of XUL is to create re-useable widgets that are made up out of several +smaller XUL elements. These widgets can be bound to the DOM using something +called the `XML binding language (XBL)`_. + +The end result is that the DOM sees the widget as a single entity. It doesn't +know anything about how that widget is made up. All of the smaller XUL elements +that make up the widget are called `anonymous content`_. It is not possible to +query such elements using traditional DOM methods like `getElementById`. + +Marionette provides two special strategies used for finding anonymous content. +Unlike normal elements, anonymous nodes can only be seen by their parent. So +it's necessary to first find the parent element and then search for the +anonymous children from there. + +* `anon` - Finds all anonymous children of the element, there is no search term + so `None` must be passed in:: + + anon_children = client.find_element('id', 'parent').find_elements('anon', None) + +* `anon attribute` - Find an anonymous child based on an attribute. An + unofficial convention is for anonymous nodes to have an + `anonid` attribute:: + + anon_child = client.find_element('id', 'parent').find_element('anon attribute', {'anonid': 'container'}) + + +.. _XUL: https://developer.mozilla.org/en-US/docs/Mozilla/Tech/XUL +.. _XML binding language (XBL): https://developer.mozilla.org/en-US/docs/XBL +.. _anonymous content: https://developer.mozilla.org/en-US/docs/XBL/XBL_1.0_Reference/Anonymous_Content diff --git a/testing/marionette/client/docs/advanced/landing.rst b/testing/marionette/client/docs/advanced/landing.rst new file mode 100644 index 000000000..0a44de63d --- /dev/null +++ b/testing/marionette/client/docs/advanced/landing.rst @@ -0,0 +1,13 @@ +Advanced Topics +=============== + +Here are a collection of articles explaining some of the more complicated +aspects of Marionette. + +.. toctree:: + :maxdepth: 1 + + findelement + stale + actions + debug diff --git a/testing/marionette/client/docs/advanced/stale.rst b/testing/marionette/client/docs/advanced/stale.rst new file mode 100644 index 000000000..0af576865 --- /dev/null +++ b/testing/marionette/client/docs/advanced/stale.rst @@ -0,0 +1,71 @@ +Dealing with Stale Elements +=========================== +.. py:currentmodule:: marionette + +Marionette does not keep a live representation of the DOM saved. All it can do +is send commands to the Marionette server which queries the DOM on the client's +behalf. References to elements are also not passed from server to client. A +unique id is generated for each element that gets referenced and a mapping of +id to element object is stored on the server. When commands such as +:func:`~HTMLElement.click()` are run, the client sends the element's id along +with the command. The server looks up the proper DOM element in its reference +table and executes the command on it. + +In practice this means that the DOM can change state and Marionette will never +know until it sends another query. For example, look at the following HTML:: + + <head> + <script type=text/javascript> + function addDiv() { + var div = document.createElement("div"); + document.getElementById("container").appendChild(div); + } + </script> + </head> + + <body> + <div id="container"> + </div> + <input id="button" type=button onclick="addDiv();"> + </body> + +Care needs to be taken as the DOM is being modified after the page has loaded. +The following code has a race condition:: + + button = client.find_element('id', 'button') + button.click() + assert len(client.find_elements('css selector', '#container div')) > 0 + + +Explicit Waiting and Expected Conditions +---------------------------------------- + +To avoid the above scenario, manual synchronisation is needed. Waits are used +to pause program execution until a given condition is true. This is a useful +technique to employ when documents load new content or change after +``Document.readyState``'s value changes to "complete". + +The :class:`Wait` helper class provided by Marionette avoids some of the +caveats of ``time.sleep(n)``. It will return immediately once the provided +condition evaluates to true. + +To avoid the race condition in the above example, one could do:: + + button = client.find_element('id', 'button') + button.click() + + def find_divs(): + return client.find_elements('css selector', '#container div') + + divs = Wait(client).until(find_divs) + assert len(divs) > 0 + +This avoids the race condition. Because finding elements is a common condition +to wait for, it is built in to Marionette. Instead of the above, you could +write:: + + button = client.find_element('id', 'button') + button.click() + assert len(Wait(client).until(expected.elements_present('css selector', '#container div'))) > 0 + +For a full list of built-in conditions, see :mod:`~marionette.expected`. |