Thursday, October 14, 2010

Friday, October 8, 2010

A Generic Function to enhance BPT components

About 2 years ago, we created a set of QTP function libraries to drive the automation effort using Quality Center's Business Process Testing (BPT) functionality. What those libraries provide are a set of generic functions from clicking on a UI object to verifying an object's property, which then can be used to create both generic BPT components that can be used on any application and specific components that target a particular application or a screen within an application. We have used those libraries and components to successfully automate our application testing without much modification and maintenance.

Recently, we were using the same set of components to create/update the test cases for a new application and I took this opportunity to enhance the libraries by adding a few functions. One of them is a generic Eval function that provides some more flexibility in creating components. As we know, VBScript has its own Eval function that evaluates the provided expression and returns the result. So to be able to use that functionality from within the components, I created a new function that returns the result of that expression or the string itself if it is not an expression. Here's the function listing:

' Function EvalFunction
' ------------------
' Evals the function call specified in the parameter and returns the result
' Parameter: expr - Any VBScript expression
'@Description Evals the function call specified in the parameter and returns the result
'@Documentation Evals the function call specified in the parameter and returns the result
Public Function EvalFunction(ByVal expr)
  Dim res
  On Error Resume Next
  If (expr <> "") Then
    res = Eval(expr)
    If (Err <> 0)Then
      res = -1
      Err.Clear
    Elseif res = "" Then
      res = expr
    End If
  End If
  EvalFunction = res
  On Error Goto 0
End Function

The function itself is quite simple but it provides a lot of added functionality. I can use this function in my BPT components to evaluate any expression during run-time. And in addition, I also create a generic component that calls this function and returns the result. When I need to create a test case that needs a run-time value, I can use this component within my test cases to have that functionality.

Using the EvalFunction function in components:

For a part of our application's functionality, we had a component ("AddIP") that adds an IP to a user. Since there were 4 text fields for each of the octets, we had 4 component input parameters for each octet. In the picture below of AddIP component, each octet is a different text field (“IP1”…”IP4”) requiring a different input parameter (BrowserWebEditSet is another generic function to enter value in a WebEdit object)

AddIP

But while revisiting the testing, I felt that its much easier to provide the IP parameter as a whole when you're creating a large test case where multiple IPs need to be added. So instead of having to create a new function, I just used the EvalFunction to create another component ("AddIPv2") that takes the full IP address and splits it into each octet and then enters the values as required in different text boxes. I use the VBScript “split” function to split the input parameter (the IP address) into each octet like this: "Split(""" & Parameter("IP") & """,""."",-1,vbTextCompare)(0)" which returns the 1st octet. As in the picture of the component below, I call the function 4 times for each octet which returns the result in a local parameter which I can then use to set for each text field.

AddIPv2

So using this enhanced component, the user has to provide only the whole IP address “xxx.xxx.xxx.xxx” instead of each octet in a separate parameter.

Using the EvalFunction component in BPT tests:

The EvalFunction component is a one operation component that calls the EvalFunction and returns the result in a component output parameter. This component can be used in any test to evaluate any expression and use the result in a subsequent component.

EvalFunction Component

For example, a lot of our test cases require creating a new user. Instead of specifying a fixed value for the user ID or having the tester enter a value in a run-time parameter before every run of the test, the user ID can be generated using a timestamp which guarantees its uniqueness. This is done by using the EvalFunction component. In the BPT test case below, the EvalFunction component is used with input parameter a string prefix concatenated with the current timestamp (DateFormatter is another function that returns the current date/time in appropriate format). It returns the result in a component parameter “result” which is then later used in AddUser component to create a user with that user ID. 

EvalFunction Component 2

This way, this test can be run any number of times without requiring any modification.

Epilogue:

The function that I showed in this post is a part of the automation libraries that we created. Over time, as we use them for testing multiple applications, we have enhanced the libraries even more. These libraries, along with the BPT functionality provided by Quality Center, have helped us create reusable components that require very less maintenance. And these components are being used by testers to create and run automated test cases for different applications and different functionalities.