Enterprise Library Test Guide - Willy .Net

Testing for Performance and Scalability 177
After you create the test, you can convert the recorded Web test to a coded Web test.
To convert a recorded Web test
1. Open a solution that contains a recorded Web test.
2. Open the Web test file.
3. In the Web Test Editor, click the Generate Code button. You are prompted for a
name for the coded Web test.
4. Type a name, and then click OK.
5. Click Build, and then click Build Solution. Your code compiles. The compiled
code is a test script.
When you build your test harnesses, remember two points:
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Do not cache an application block's internal domain objects over iterations of the
tests to avoid the costs of creating them. Performance tests should assume the
worst case scenario, which is the most expensive code path. For example, the
Caching Application Block's most expensive code path is when the application
block creates a CacheManager object. The most expensive path for the Logging
Application Block is when the application block creates a LogEntry object. For an
example of how to create a CacheManager object, see Using the Test Script.
Do not distort the TPS measurements made with the performance monitor (ASP.
NET: Requests/sec) and the Visual Studio 2005 Team Edition for Software Testers
load test tool by reloading the Web page after the first request. Instead, read the
ViewState and EventValidation variables (and any other static variables that the
Web server returns).
There are two ways to implement these suggestions. You can either edit the test script
or you can use data binding. For information about editing the test script, see Using
the Test Script. For information about using data binding, see Using Data Binding.
Using the Test Script
You can add code to the test script to maintain the state of the Web page. This means
that the entire page is loaded only once, when the first user accesses it. The values
from the page and all of the controls are collected and formatted into a single encoded
string and then saved in the _VIEWSTATE hidden field. In the example given
here, the test script stores this string in the ViewState variable. The test script tests
the ViewState variable to see if it is null. This is the equivalent of seeing if this is the
first time the page has been loaded. If the value is not null, the test script reloads the
page but executes only the POST request path, along with the required test actions.
The test script also uses the __EVENTVALIDATION hidden field. This field acts as
security against fraudulent postbacks. It validates any events (such as clicking a button)
that occur. The EventValidation variable stores the value of the field.