Selectors
The WebDriver Protocol provides several selector strategies to query an element. WebdriverIO simplifies them to keep selecting elements simple. Please note that even though the command to query elements is called $
and $$
, they have nothing to do with jQuery or the Sizzle Selector Engine. The following selector types are supported:
#
CSS Query Selector#
Link TextTo get an anchor element with a specific text in it, query the text starting with an equals (=
) sign.
For example:
You can query this element by calling:
#
Partial Link TextTo find a anchor element whose visible text partially matches your search value,
query it by using *=
in front of the query string (e.g. *=driver
).
You can query this element by calling:
Note: You can't mix multiple selector strategies in one selector. Use multiple chained element queries to reach the same goal, e.g.:
#
Element with certain textThe same technique can be applied to elements as well.
For example, here's a query for a level 1 heading with the text "Welcome to my Page":
You can query this element by calling:
Or using query partial text:
The same works for id
and class
names:
You can query this element by calling:
Note: You can't mix multiple selector strategies in one selector. Use multiple chained element queries to reach the same goal, e.g.:
#
Tag NameTo query an element with a specific tag name, use <tag>
or <tag />
.
You can query this element by calling:
#
Name AttributeFor querying elements with a specific name attribute you can either use a normal CSS3 selector or the provided name strategy from the JSONWireProtocol by passing something like [name="some-name"] as selector parameter:
Note: This selector strategy it depcrecated and only works in old browser that are run by the JSONWireProtocol protocol or by using Appium.
#
xPathIt is also possible to query elements via a specific xPath.
An xPath selector has a format like //body/div[6]/div[1]/span[1]
.
You can query the second paragraph by calling:
You can use xPath to also traverse up and down the DOM tree:
#
idFinding element by id has no specific syntax in WebDriver and one should use either CSS selectors (#<my element ID>
) or xPath (//*[@id="<my element ID>"]
).
However some drivers (e.g. Appium You.i Engine Driver) might still support this selector.
#
JS FunctionYou can also use Javascript functions to fetch elements using web native APIs. Of course, you can only do this inside a web context (e.g., browser
, or web context in mobile).
Given the following HTML structure:
You can query the sibling element of #elem
as follows:
#
Mobile SelectorsFor hybrid mobile testing, it's important that the automation server is in the correct context before executing commands. For automating gestures, the driver ideally should be set to native context. But to select elements from the DOM, the driver will need to be set to the platform's webview context. Only then can the methods mentioned above can be used.
For native mobile testing, there is no switching between contexts, as you have to use mobile strategies and use the underlying device automation technology directly. This is especially useful when a test needs some fine-grained control over finding elements.
#
Android UiAutomatorAndroid’s UI Automator framework provides a number of ways to find elements. You can use the UI Automator API, in particular the UiSelector class to locate elements. In Appium you send the Java code, as a string, to the server, which executes it in the application’s environment, returning the element or elements.
#
Android DataMatcher and ViewMatcher (Espresso only)Android's DataMatcher strategy provides a way to find elements by Data Matcher
And similarly View Matcher
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Android View Tag (Espresso only)The view tag strategy provides a convenient way to find elements by their tag.
#
iOS UIAutomationWhen automating an iOS application, Apple’s UI Automation framework can be used to find elements.
This JavaScript API has methods to access to the view and everything on it.
You can also use predicate searching within iOS UI Automation in Appium to refine element selection even further. See here for details.
#
iOS XCUITest predicate strings and class chainsWith iOS 10 and above (using the XCUITest
driver), you can use predicate strings:
And class chains:
#
Accessibility IDThe accessibility id
locator strategy is designed to read a unique identifier for a UI element. This has the benefit of not changing during localization or any other process that might change text. In addition, it can be an aid in creating cross-platform tests, if elements that are functionally the same have the same accessibility id.
- For iOS this is the
accessibility identifier
laid out by Apple here. - For Android the
accessibility id
maps to thecontent-description
for the element, as described here.
For both platforms, getting an element (or multiple elements) by their accessibility id
is usually the best method. It is also the preferred way over the deprecated name
strategy.
#
Class NameThe class name
strategy is a string
representing a UI element on the current view.
- For iOS it is the full name of a UIAutomation class, and will begin with
UIA-
, such asUIATextField
for a text field. A full reference can be found here. - For Android it is the fully qualified name of a UI Automator class, such
android.widget.EditText
for a text field. A full reference can be found here. - For Youi.tv it is the full name of a Youi.tv class, and will being with
CYI-
, such asCYIPushButtonView
for a push button element. A full reference can be found at You.i Engine Driver's GitHub page
#
Chain SelectorsIf you want to be more specific in your query, you can chain selectors until you've found the right
element. If you call element
before your actual command, WebdriverIO starts the query from that element.
For example, if you have a DOM structure like:
And you want to add product B to the cart, it would be difficult to do that just by using the CSS selector.
With selector chaining, it's way easier. Simply narrow down the desired element step by step:
#
Appium Image SelectorUsing the -image
locator strategy, it is possible to send an Appium an image file representing an element you want to access.
Supported file formats jpg,png,gif,bmp,svg
Full reference can be found here
Note: The way how Appium works with this selector is that it will internally make a (app)screenshot and use the provided image selector to verify if the element can be found in that (app)screenshot.
Be aware of the fact that Appium might resize the taken (app)screenshot to make it match the CSS-size of your (app)screen (this will happen on iPhones but also on Mac machines with a Retina display because the DPR is bigger than 1). This will result in not finding a match because the provided image selector might have been taken from the original screenshot. You can fix this by updating the Appium Server settings, see the Appium docs for the settings and this comment on a detailed explanation.
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React SelectorsWebdriverIO provides a way to select React components based on the component name. To do this, you have a choice of two commands: react$
and react$$
.
These commands allow you to select components off the React VirtualDOM and return either a single WebdriverIO Element or an array of elements (depending on which function is used).
Note: The commands react$
and react$$
are similar in functionality, except that react$$
will return all matching instances as an array of WebdriverIO elements, and react$
will return the first found instance.
#
Basic exampleIn the above code there is a simple MyComponent
instance inside the application, which React is rendering inside a HTML element with id="root"
.
With the browser.react$
command, you can select an instance of MyComponent
:
Now that you have the WebdriverIO element stored in myCmp
variable, you can execute element commands against it.
#
Filtering componentsThe library that WebdriverIO uses internally allows to filter your selection by props and/or state of the component. To do so, you need to pass a second argument for props and/or a third argument for state to the browser command.
If you want to select the instance of MyComponent
that has a prop name
as WebdriverIO
, you can execute the command like so:
If you wanted to filter our selection by state, the browser
command would looks something like so:
React.Fragment
#
Dealing with When using the react$
command to select React fragments, WebdriverIO will return the first child of that component as the component's node. If you use react$$
, you will receive an array containing all the HTML nodes inside the fragments that match the selector.
Given the above example, this is how the commands would work:
Note: If you have multiple instances of MyComponent
and you use react$$
to select these fragment components, you will be returned an one-dimensional array of all the nodes. In other words, if you have 3 <MyComponent />
instances, you will be returned an array with six WebdriverIO elements.
#
Custom Selector StrategiesIf your app requires a specific way to fetch elements you can define yourself a custom selector strategy that you can use with custom$
and custom$$
. For that register your strategy once in the beginning of the test:
The use it by calling:
Note: this only works in an web environment in which the execute
command can be run.