MSCFOSS/DIF122/Software Development Practices/Unit IV/Testing tools Selenium
Selenium automates browsers. That's it. What you do with that power is entirely up to you. Primarily it is for automating web applications for testing purposes, but is certainly not limited to just that. Boring web-based administration tasks can (and should!) also be automated as well.
Selenium has the support of some of the largest browser vendors who have taken (or are taking) steps to make Selenium a native part of their browser. It is also the core technology in countless other browser automation tools, APIs and frameworks.
The Selenium-IDE (Integrated Development Environment) is the tool you use to develop your Selenium test cases. It’s an easy-to-use Firefox plug-in and is generally the most efficient way to develop test cases. It also contains a context menu that allows you to first select a UI element from the browser’s currently displayed page and then select from a list of Selenium commands with parameters pre-defined according to the context of the selected UI element. This is not only a time-saver, but also an excellent way of learning Selenium script syntax.
This chapter is all about the Selenium IDE and how to use it effectively.
Installing the IDE
Firefox will protect you from installing addons from unfamiliar locations, so you will need to click ‘Allow’ to proceed with the installation, as shown in the following screenshot.
When downloading from Firefox, you’ll be presented with the following window.
Select Install Now. The Firefox Add-ons window pops up, first showing a progress bar, and when the download is complete, displays the following.
Restart Firefox. After Firefox reboots you will find the Selenium-IDE listed under the Firefox Tools menu.
Opening the IDE
To run the Selenium-IDE, simply select it from the Firefox Tools menu. It opens as follows with an empty script-editing window and a menu for loading, or creating new test cases.
The File menu has options for Test Case and Test Suite (suite of Test Cases). Using these you can add a new Test Case, open a Test Case, save a Test Case, export Test Case in a language of your choice. You can also open the recent Test Case.All these options are also available for Test Suite.
The Edit menu allows copy, paste, delete, undo, and select all operations for editing the commands in your test case. The Options menu allows the changing of settings. You can set the timeout value for certain commands, add user-defined user extensions to the base set of Selenium commands, and specify the format (language) used when saving your test cases. The Help menu is the standard Firefox Help menu; only one item on this menu–UI-Element Documentation–pertains to Selenium-IDE.
The toolbar contains buttons for controlling the execution of your test cases, including a step feature for debugging your test cases. The right-most button, the one with the red-dot, is the record button
Speed Control: controls how fast your test case runs.
Run All: Runs the entire test suite when a test suite with multiple test cases is loaded.
Run: Runs the currently selected test. When only a single test is loaded this button and the Run All button have the same effect.
Pause/Resume: Allows stopping and re-starting of a running test case.
Step: Allows you to “step” through a test case by running it one command at a time. Use for debugging test cases.
TestRunner Mode: Allows you to run the test case in a browser loaded with the Selenium-Core TestRunner. The TestRunner is not commonly used now and is likely to be deprecated. This button is for evaluating test cases for backwards compatibility with the TestRunner. Most users will probably not need this button.
Apply Rollup Rules: This advanced feature allows repetitive sequences of Selenium commands to be grouped into a single action. Detailed documentation on rollup rules can be found in the UI-Element Documentation on the Help menu.
Record: Records the user’s browser actions.
Test Case Pane
Your script is displayed in the test case pane. It has two tabs, one for displaying the command and their parameters in a readable “table” format.
The other tab - Source displays the test case in the native format in which the file will be stored. By default, this is HTML although it can be changed to a programming language such as Java or C#, or a scripting language like Python. See the Options menu for details. The Source view also allows one to edit the test case in its raw form, including copy, cut and paste operations.
The Command, Target, and Value entry fields display the currently selected command along with its parameters. These are entry fields where you can modify the currently selected command. The first parameter specified for a command in the Reference tab of the bottom pane always goes in the Target field. If a second parameter is specified by the Reference tab, it always goes in the Value field.
If you start typing in the Command field, a drop-down list will be populated based on the first characters you type; you can then select your desired command from the drop-down.
The bottom pane is used for four different functions–Log, Reference, UI-Element, and Rollup–depending on which tab is selected.
When you run your test case, error messages and information messages showing the progress are displayed in this pane automatically, even if you do not first select the Log tab. These messages are often useful for test case debugging. Notice the Clear button for clearing the Log. Also notice the Info button is a drop-down allowing selection of different levels of information to log.
The Reference tab is the default selection whenever you are entering or modifying Selenese commands and parameters in Table mode. In Table mode, the Reference pane will display documentation on the current command. When entering or modifying commands, whether from Table or Source mode, it is critically important to ensure that the parameters specified in the Target and Value fields match those specified in the parameter list in the Reference pane. The number of parameters provided must match the number specified, the order of parameters provided must match the order specified, and the type of parameters provided must match the type specified. If there is a mismatch in any of these three areas, the command will not run correctly.
While the Reference tab is invaluable as a quick reference, it is still often necessary to consult the Selenium Reference document.
UI-Element and Rollup
Detailed information on these two panes (which cover advanced features) can be found in the UI-Element Documentation on the Help menu of Selenium-IDE.
Building Test Cases
There are three primary methods for developing test cases. Frequently, a test developer will require all three techniques.
Many first-time users begin by recording a test case from their interactions with a website. When Selenium-IDE is first opened, the record button is ON by default. If you do not want Selenium-IDE to begin recording automatically you can turn this off by going under Options > Options... and deselecting “Start recording immediately on open.”
During recording, Selenium-IDE will automatically insert commands into your test case based on your actions. Typically, this will include:
- clicking a link - click or clickAndWait commands
- entering values - type command
- selecting options from a drop-down listbox - select command
- clicking checkboxes or radio buttons - click command
Here are some “gotchas” to be aware of:
- The type command may require clicking on some other area of the web page for it to record.
- Following a link usually records a click command. You will often need to change this to clickAndWait to ensure your test case pauses until the new page is completely loaded. Otherwise, your test case will continue running commands before the page has loaded all its UI elements. This will cause unexpected test case failures.
Adding Verifications and Asserts With the Context Menu
Your test cases will also need to check the properties of a web-page. This requires assert and verify commands. We won’t describe the specifics of these commands here; that is in the chapter on Selenium Commands – “Selenese”. Here we’ll simply describe how to add them to your test case.
With Selenium-IDE recording, go to the browser displaying your test application and right click anywhere on the page. You will see a context menu showing verify and/or assert commands.
The first time you use Selenium, there may only be one Selenium command listed. As you use the IDE however, you will find additional commands will quickly be added to this menu. Selenium-IDE will attempt to predict what command, along with the parameters, you will need for a selected UI element on the current web-page.
Let’s see how this works. Open a web-page of your choosing and select a block of text on the page. A paragraph or a heading will work fine. Now, right-click the selected text. The context menu should give you a verifyTextPresent command and the suggested parameter should be the text itself.
Also, notice the Show All Available Commands menu option. This shows many, many more commands, again, along with suggested parameters, for testing your currently selected UI element.
Try a few more UI elements. Try right-clicking an image, or a user control like a button or a checkbox. You may need to use Show All Available Commands to see options other than verifyTextPresent. Once you select these other options, the more commonly used ones will show up on the primary context menu. For example, selecting verifyElementPresent for an image should later cause that command to be available on the primary context menu the next time you select an image and right-click.
Again, these commands will be explained in detail in the chapter on Selenium commands. For now though, feel free to use the IDE to record and select commands into a test case and then run it. You can learn a lot about the Selenium commands simply by experimenting with the IDE.
Select the point in your test case where you want to insert the command. To do this, in the Test Case Pane, left-click on the line where you want to insert a new command. Right-click and select Insert Command; the IDE will add a blank line just ahead of the line you selected. Now use the command editing text fields to enter your new command and its parameters.
Select the point in your test case where you want to insert the command. To do this, in the Test Case Pane, left-click between the commands where you want to insert a new command, and enter the HTML tags needed to create a 3-column row containing the Command, first parameter (if one is required by the Command), and second parameter (again, if one is required). Be sure to save your test before switching back to Table view. Insert Comment
Comments may be added to make your test case more readable. These comments are ignored when the test case is run.
Comments may also be used to add vertical white space (one or more blank lines) in your tests; just create empty comments. An empty command will cause an error during execution; an empty comment won’t.
Select the line in your test case where you want to insert the comment. Right-click and select Insert Comment. Now use the Command field to enter the comment. Your comment will appear in purple text.
Select the point in your test case where you want to insert the comment. Add an HTML-style comment, i.e., .
Edit a Command or Comment
Simply select the line to be changed and edit it using the Command, Target, and Value fields.
Since Source view provides the equivalent of a WYSIWYG (What You See is What You Get) editor, simply modify which line you wish–command, parameter, or comment.
Opening and Saving a Test Case
Like most programs, there are Save and Open commands under the File menu. However, Selenium distinguishes between test cases and test suites. To save your Selenium-IDE tests for later use you can either save the individual test cases, or save the test suite. If the test cases of your test suite have not been saved, you’ll be prompted to save them before saving the test suite.
When you open an existing test case or suite, Selenium-IDE displays its Selenium commands in the Test Case Pane.
Running Test Cases
The IDE allows many options for running your test case. You can run a test case all at once, stop and start it, run it one line at a time, run a single command you are currently developing, and you can do a batch run of an entire test suite. Execution of test cases is very flexible in the IDE.
Run a Test Case
Click the Run button to run the currently displayed test case.
Run a Test Suite
Click the Run All button to run all the test cases in the currently loaded test suite.
Stop and Start
The Pause button can be used to stop the test case while it is running. The icon of this button then changes to indicate the Resume button. To continue click Resume.
Stop in the Middle
You can set a breakpoint in the test case to cause it to stop on a particular command. This is useful for debugging your test case. To set a breakpoint, select a command, right-click, and from the context menu select Toggle Breakpoint.
Start from the Middle
You can tell the IDE to begin running from a specific command in the middle of the test case. This also is used for debugging. To set a startpoint, select a command, right-click, and from the context menu select Set/Clear Start Point.
Run Any Single Command
Double-click any single command to run it by itself. This is useful when writing a single command. It lets you immediately test a command you are constructing, when you are not sure if it is correct. You can double-click it to see if it runs correctly. This is also available from the context menu.