Error Handling using vbscript in QTP

Introduction:

Unexpected events during a test run disrupt a test or may give invalid test results. For example, during a test run, an application error may occur. This error does not permit the automated test to navigate to the feature, screen, or module that needs to be tested. These unexpected errors and events are called exceptions. It becomes important to handle these exceptions so that we are able to continue with automated testing even in unattended mode. Handling of exception in a manner so that test execution is uninterrupted is known as error handling.

Following are the ways in which error handling can be implemented in QTP.

•       VB Script Error Handling

o   Using Test Settings

o   Using On Error Statement

o   Using Err Object Properties

o   Using Exit Statement

•       Recovery Scenarios

Test Settings : Error Handling

Error Handling can be defined  in Test Settings through File>Settings>Run as shown below:

It defines the possible actions in case  an error is encountered during run session

Test Settings for error handling

Using On Error Statement

•       On Error Statement

On Error statement, which informs the VBScript engine of intention to handle errors by self, rather than to allow the VBScript engine to display a typically uninformative error message and halt the program. This is done by inserting a statement like the following at the start of a procedure:      

•       On Error Resume Next: On Error Resume Next tells the VBScript engine that, should an error occur, we want it to continue executing the program starting with the line of code that directly follows the line in which the error occurred.

•       On error Goto 0: This turns off the error handling

Err Object Properties and Methods

The Err object is part of the VBScript language and contains information about the last error to occur. Some of the most useful properties and method of Err object are as follows:

Err.Number Property: The Number property returns or sets a numeric value specifying an error. Number is the Err object's default property.If the value of Err.Number is 0, no error has occurred.

Err.Description Property: The Description property returns or sets a descriptive string associated with an error.    

            

Err.Clear Method: The Clear method clears all property settings of the Err object.

Following is a code snippet how error handling can be implemented programmatically.

Public  Function  FunctER()

On error resume next

Lines of code

If (err.number<>0) then

       Reporter.ReportEvent micFail, “Func1", err.description

Else

      Reporter.ReportEvent micFail, “Func1", “Function executed”

End If

Err.clear

End Function

Using Exit Statement:

Exit Statement can be used in conjunction with err object to exit from a test/action/iteration in case of an error encountered. Following are the exit statements that can be used in QTP to exit from a particular state:

ExitTest: Exits the entire QTP test or Quality Center business process test, regardless of the run-time iteration settings.

ExitAction: Exits the current action.

ExitActionIteration: Exits the current iteration of the action.   

ExitTestIteration:  Exits the current iteration of the QTP test or Quality Center business process test and proceeds to the next iteration.