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ManipulateSettingsWithSeleniumConfig.md

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Selenium Foundation Project Configuration

The configuration of Selenium Foundation projects is an aggregation of several factors:

  • Project specification (e.g. - pom.xml, build.gradle)
  • ServiceLoader provider configuration files:
    • Specification of driver plug-ins for local Grid
    • Specification of TestNG listener classes
    • Specification of JUnit watcher classes
  • Configuration settings for...

Note that configuration settings can be overridden via System properties, and reasonable defaults are provided where they make sense. More on this in the next section.

Generic Interfaces to Version-Specific Features

Each release of Selenium Foundation is published in two flavors: s2 for Selenium 2 and s3 for Selenium 3. Most of the code in this project is version-agnostic, built on interfaces that are consistent between the two major versions of the Selenium API. Functionality implemented with interfaces that differ between Selenium 2 and Selenium 3 is contained in flavor-specific folders in the Selenium Foundation project (java-s2 and java-s3). These features include:

  • Concrete configuration: com.nordstrom.automation.selenium.SeleniumConfig
  • Driver wrapper: com.nordstrom.automation.selenium.interfaces.WrapsDriver
  • JSON data utility: com.nordstrom.automation.selenium.utility.DataUtils
  • Local Grid driver plug-ins: com.nordstrom.automation.selenium.plugins.*

Concrete Configuration (SeleniumConfig)

SeleniumConfig declares settings and methods related to Selenium WebDriver and Grid configuration. This class is built on the Settings API, composed of defaults, stored values, and System properties. SeleniumSettings declares the constants, property names, and default values for the settings managed by SeleniumConfig. Defaults can be overridden via System properties or the settings.properties file typically found in your user "home" directory.

The configuration object itself is maintained as a static singleton, ubiquitously available through a static method of the abstract base class:

SeleniumConfig config = AbstractSeleniumConfig.getConfig();

OVERRIDING DEFAULTS

SeleniumConfig searches a series of locations for a settings.properties file. This file will typically be stored in your user "home" folder. Any settings declared in this file will override the defaults assigned in the SeleniumSettings enumeration. Settings that are declared as System properties will override both the defaults assigned by SeleniumSettings and settings declared in settings.properties. For example:

settings.properties
selenium.target.host=my.server.com
selenium.browser.name=chrome

This sample settings.properties file overrides the values of TARGET_HOST and BROWSER_NAME. The latter can be overridden by System property declaration:

-Dselenium.browser.name=firefox

The hierarchy of evaluation produces the following results:

BROWSER_NAME = firefox; TARGET_HOST = my.server.com; TARGET_PATH = /

Location Strategy for settings.properties

As mentioned previously, you're able to override defaults in SeleniumConfig with values defined in a settings.properties file. This file is typically stored in your user "home" folder, but Selenium Foundation employs a file location strategy that searches for settings.properties in a number of places. This strategy is described in detail under DEFAULT_LOCATION_STRATEGY in the documentation for Apache Commons Configuration.

Configuration-Based API Abstration

SeleniumConfig is more than a collection of settings; this class also provides generic interfaces to several core aspects of the WebDriver API that differ between Selenium 2 and Selenium 3:

  • Convert JSON string to Capabilities object: getCapabilitiesForJson(String capabilities)
  • Convert object to JSON string: toJson(Object obj)
  • Get context class names for Grid dependencies: getDependencyContexts()
  • Create Grid node configuration file from JSON: createNodeConfig(String jsonStr, URL hubUrl)

SeleniumConfig also provides version-specific default values for several settings:

Setting s2 Default s3 Default
GRID_LAUNCHER org.openqa.grid.selenium.GridLauncher org.openqa.grid.selenium.GridLauncherV3
HUB_PORT 4444 4445
NODE_CONFIG nodeConfig-s2.json nodeConfig-s3.json

THE SeleniumSettings OBJECT

The static getConfig() method returns a SeleniumConfig object that provides settings and methods related to Selenium WebDriver and Grid configuration. The individual settings managed by SeleniumConfig are declared by the SeleniumSettings enumeration. The following sections provide the details of these settings - constants, property names, defaults, interrelationships, and utilization.

Selenium Grid Configuration

SeleniumConfig provides several methods related to local and remote Selenium Grid configuration:

  • getHubUrl() - Get the URL for the configured Selenium Grid hub host. If the current configuration doesn't specify a hub host, but defines a hub port, a localhost URL is assembled.
  • getSeleniumGrid() - Get an object that represents the active Selenium Grid.
  • shutdownGrid(boolean localOnly) - Shut down the active Selenium Grid.

As indicated previously, the set of drivers supported by the local Grid instance managed by Selenium Foundation is configured with a ServiceLoader provider configuration file. Note that the file that link connects to isn't just a static sample file; it's the actual provider configuration file for the project unit tests.

As of this writing, the unit tests are configured to use HtmlUnit. Described as "a GUI-less browser for Java programs", this browser is perfect for rendering the simple pages used to exercise the features of Selenium Foundation. In addition to this ServiceLoader configuration file, the Java project itself must declare the dependencies that are required by the corresponding driver. These dependencies are dependent on the version of Selenium API you're using, and they're documented in the plug-in classes themselves.

Here are the Maven dependencies for the Selenium 2 version of HtmlUnitPlugin:

<dependency>
  <groupId>net.sourceforge.htmlunit</groupId>
  <artifactId>htmlunit</artifactId>
  <version>2.22</version>
</dependency>
<dependency>
  <groupId>org.seleniumhq.selenium</groupId>
  <artifactId>htmlunit-driver</artifactId>
  <version>2.22</version>
</dependency>

Currently, plug-ins are provided for the following browsers:

Browser Selenium 2 Selenium 3
Chrome src src
Firefox src src
HtmlUnit src src
PhantomJS src src

Note that Selenium Foundation also includes plug-ins for Edge, Internet Explorer, Opera, and Safari - but at the time of this writing, the drivers for these browsers don't appear to be functional.

Browser Capabilities

The getCurrentCapabilities() method converts the configured browser settings into a Capabilities object:

  • If BROWSER_NAME is specified, Selenium Foundation uses this name to acquire a Capabilities object from the active Selenium Grid.
  • Otherwise, the JSON configuration is acquired from BROWSER_CAPS.

As indicated by the sequence above, the desired browser can be specified solely by name. This name can be associated with a Selenium Grid browser "personality", or it may simply specify the name associated with a particular browser by its corresponding driver. If browser name is omitted, a fully-specified JSON capabilities record is acquired from the settings collection. (By default, the browser capabilities setting specifies the HtmlUnit browser.)

The getCapabilitiesForName(String browserName) method enables you to get a Capabilities object for a specified name or "personality" from the active Selenium Grid. This bypasses the configured default browser specification, allowing you to acquire browser sessions of any type supported by the active Grid.

Testing with non-default browser sessions

The easiest way to provide non-default browser sessions to your test methods is to implement the DriverProvider interface:

public class MyChromeTest extends TestNgBase implements DriverProvider {
    
    ...
    
    @Override
    public WebDriver provideDriver(Method method) {
        SeleniumConfig config = AbstractSeleniumConfig.getConfig();
        URL remoteAddress = config.getSeleniumGrid().getHubServer().getUrl();
        Capabilities desiredCapabilities = config.getCapabilitiesForName("chrome");
        return GridUtility.getDriver(remoteAddress, desiredCapabilities);
    }
}

With this implementation, every test method will be provided with a Chrome browser session regardless of configured default browser specification. Note that the active Selenium Grid must be configured to support Chrome for this to actually work.

Target Application URI

SeleniumConfig provides a getTargetUri() method that assembles the URI of the target application from five discrete settings:

Constant Property Name Default
TARGET_SCHEME selenium.target.scheme http
TARGET_CREDS selenium.target.creds (none)
TARGET_HOST selenium.target.host localhost
TARGET_PORT selenium.target.port (none)
TARGET_PATH selenium.target.path /

TARGET_PORT enables you to specify a non-default port number. TARGET_PATH enables you to specify a base path from which all pages originate. TARGET_CREDS is used to provide credentials in standard URL format.

Timeout Settings and the WaitType Enumeration

The following table documents the timeout settings defined by Selenium Foundation:

Constant Property Name Default Description
PAGE_LOAD_TIMEOUT selenium.timeout.pageload 30 Driver page load timeout interval; also used by page load completion and landing page verification features.
IMPLIED_TIMEOUT selenium.timeout.implied 15 Driver implicit wait timeout interval; also used by stale element reference refresh feature.
SCRIPT_TIMEOUT selenium.timeout.script 30 Driver asynchronous script timeout interval.
WAIT_TIMEOUT selenium.timeout.wait 15 Selenium Foundation search context wait timeout interval.
HOST_TIMEOUT selenium.timeout.host 30 Selenium Foundation HTTP host wait timeout interval.

Typically, these settings are not accessed directly. Rather, they are proxied through the WaitType enumeration to streamline the process of reading the timeout intervals and acquiring search context wait objects.