Enhancing the Test Plan
As you have seen we have added some basic elements to the Test Plan like Sampler and some listeners. Similarly you can add many other elements in your Test Plan as shown under Group heading.
| Group | Purpose |
| Samplers | The requests to the servers are being sent by these elements for the request types SOAP, JDBC,"Java", HTTP/HTTPS, FTP, |
| Listeners | The results of the run can be saved by these elements in the single request, tabular forms etc by saving the results in a named file. |
| Timers | To make the test more realistic we use Timers element to insert delays between the requests. |
| Logic | Logic controllers are used if you have defined the request to be executed on some logic like if-then-else and loop structures in Java etc. |
| Configuration Elements | common information about the requests is added to work with samplers using this element. |
| Assertions | This element is used to check whether you are getting the responses within a given amount of time containing the expected data or not. |
What does Apache JMeter do?
- Loads and does the performance test for HTTP and FTP servers and arbitrary database queries.
- Does the Caching and offline analysis of test results.
- concurrent sampling by many threads as well as sampling of different functions by seperate thread groups simultaneously.
- Its extensibility
includes:
supports Scriptable Samplers such as BeanShell and BSF-compatible languages.
More extendibility and personalization allowed by Data analysis and visualization.
Unlimited testing capabilities by Pluggable Samplers. - Complete portability
- Faster operation and more precise timings is done by GUI design.
- Supports Full Swing and lightweight component.
JMeter is not a browser
Well, don't take it as a browser at all because Jmeter does not perform the actions supported by browsers as far as web-services and remote services are concerned. No Javascript is executed by the JMeter found in HTML pages. However it sometimes happens that the response could be viewed as HTML etc excluding the timings in any samples. Remember, you can view only one sample in one thread at a time.
Error reporting
Errors and warnings are also depicted by the JMeter. These errors and warnings are reported to the jmeter.log file by the JMeter including some information which runs itself on the test. Some errors which are not depicted by the JMeter may appear on the command console. You need to check the log file for any errors being reported if in case the test performed by you is not going the way to be expected. For instance a syntax error in a function call might be reported in the log file.
The errors which are not trapped and logged by the JMeter get stored as attributes of the sample result. For instance sampling errors like HTTP 404 - file not found etc get stored as attributes of the sample result.