All you need to know about JMeter – Performance Testing

Jmeter Tutorial blog by us will help you in getting about the famous tool and what’s it is used for.  Normally, Apache JMeter is employed for performance testing. Performance testing is one of the significant testing to be done on AUT. It will let you recognize the load which your application can handle and what happens if that load exceeds designated limits.

About JMeter

JMeter is an open-source software which is produced by Apache Foundation. It is used to employ load to AUT to know its performance. With the help of JMeter, you will be capable to implement a heavy load to the application with concurrent or multiple traffic to emulate real-time user behavior.

JMeter is normally employed for testing web or FTP applications. With JMeter, you will be able to recognize how many concurrent users a server can manage.

Thinking of hitting Amazon with 1000 concurrent users. For completing the scenario, you cannot obtain 1000 machines to accomplish the behavior. JMeter enables you to hit Amazon’s server with 1000 requests concurrently. JMeter simulated real-time user behavior effectively.

JMeter sends requests to the target server and then recovers the statistical information of the server. With this information, it creates test reports in different formats. 

Some advantages which you obtain via JMeter are a User-friendly GUI, easy installation, Graphical Test Results, and platform independence. It has an astonishing record and playback feature which makes it very simple to learn even for the beginner. Also, its script test can be combined with Selenium tests and beach shells for more robust automated testing. 

Step-by-step  Jmeter tutorial

How to Download and Install Apache JMeter

JMeter is a java application and it requires Java in the machine so that it can operate seamlessly. JMeter can be installed in Windows, Ubuntu, Linux, and Mac operating systems. Before installing JMeter, ensure that you have Java installed in your machine. You can check by running the command in your terminal. java -version.

1. Now it is the moment to download JMeter. Download the latest version. Download the binary file also.

2. The installation of JMeter is very simple. The download binary file must be unzipped into the folder where you require to download JMeter.

3. Run JMeter in GUI mode by clicking on the bin folder and then the jmeter.bat file. 

4. After clicking, JMeter will open.

More on Thread Group, Samplers, Listeners, and Configuration of JMeter

• Thread Group is essentially the application of multiple threads to AUT. Each thread describes one user who is accessing the application. With the help of the thread group, you can implement a number of threads which is determined by you. 

• Samplers enable JMeter to support the testing of various protocols such as HTTP, FTP, JDBC, and others. 

• FTP Request:  If you need to do performance testing for the FTP server then you can utilize the config element of the FTP request. You can send a download file or upload a file request to the FTP server. You require to add parameters to the sampler such as server name, port number, remote file name (to be downloaded or uploaded), username, and password. 

• HTTP request: With the help of the HTTP request sampler, you can request an HTTP request to the server. With the help of this request, you can recover HTML files and images from the server. 

• JDBC request: With the help of a JDBC request sampler, you can implement database performance testing. You will be capable to send a JDBC request to the server. You should be able to append the SQL query in the query tag. 

• SMTP Server: If you need to test the mail server then you must utilize the SMTP server sampler. With this protocol, we can send emails. 

• CSV Data set Config: If you want to test the website with various users who are having several credentials, you must take the help of CSV data to fix the config to pass the credentials. You can collect the credentials in the text file. It will understand lines from the file using a delimiter. You must transfer the data in a text file.

• HTTP Cookie Manager: When you log in to some website then your browser stores cookies so that you do not have to log in repeatedly. Similarly, an HTTP cookie manager also does the same task for you. If the website is returning cookies in response, then it will save a cookie for you to manage a session.  You can add an HTTP cookie manager to your test plan with the help of the config element. When you will record sessions using Blaze meter, it will automatically record cookies in the HTTP cookie manager. 

• Listeners: Listeners listen to the outcomes obtained by the JMeter and let you analyze the results with the help of visual reports. 

• View Results Tree: You get to see all the user requests in HTML format utilizing the view results listener. 

• Aggregate Reports: With the help of aggregate reports, you can receive total samples, average, median, minimum, maximum, and throughput. 

• Jmeter Timers: Once you begin sending requests to your AUT, you should have timers among each request so that it can affect real-time behavior and the server does not get confused with so many requests hitting the server. Let us see the various kinds of timers that we can combine to simulate real-time behavior. 

• Constant Timer: It delays all requests by the same amount of time. 

• Gaussian Random Timer: It delays every request by any random amount of time. You can determine the deviation around which the delays would be fixed. Also, offset can be added with the gaussian distribution of deviation amount and then the total delay time can be calculated. 

The most used timers are constant and gaussian timers.

Assertions in JMeter

Assertions are very helpful in any kind of testing as verification and validation are the heart of testing. You must compare the outcomes with the required results to understand if we are getting the correct response or not. Let us have a glance at the various common types of assertions. 

Response assertion

It enables you to check the response against pattern strings. Take an instance of Amazon.com. If you run the server with some product then the response list should contain the product specified in the search list provided in the request payload. 

You can pick a text response and add the test which you want to verify. I have appended the text in patterns to test. 

Also, we can verify the status code with the response assertion. Select the field to test as a response code and consider the code in the patterns to test. 

Duration Assertion

It tests that the server’s response is accepted by time limits. If it is exercising more than the time stated, then the assertion will be failed. 

Size Assertion

It examines the response that has the required number of bytes contained in it. If it is above the defined limit, then the assertion will be failed. If the response has equal or less than 5000 bytes then the assertion will be transferred. 

XML and HTML Assertion

XML assertion checks that the response data has the right XML syntax while HTML assertion proves that the HTML syntax of response is correct. 

Controllers in JMeter

Controllers are utilized in JMeter to handle requests in an orderly manner. There are various kinds of controllers that can be combined with the JMeter Test Plan. These controllers let you manage the order of requests to be sent to the server. Let us have a peek at different kinds of controllers. 

Recording Controller

JMeter will record your testing steps but for collecting them in a container you need a recording controller. 

Simple Controller

Simpler Controller is just a container to collect your requests. You can give a meaningful name to the controller. In this method, if you require to duplicate the requests, you can easily add the simple controller without again and again appending so many requests. It is just for clubbing requests and in the view, results graph you will not observe any controller name. 

Loop Controller

It enables the requests to run a specified number of times or forever if the number has not been determined. 

Transaction Controller

The transaction controller is similar to the simple controller which registers the overall time for the requests to finish. It has an added benefit over a simple controller as you will be able to see the controller name which has the clubbed requests rather than the individual requests name in the view results graph. 

Module Controller

It is based on the concept of modularity which states that a set of requests can be clubbed in a simple or transaction controller. A module controller can be utilized to add any set of requests by picking the controller. Assume if you have 3 simple controllers named login, search and logout, then with the module container you will be able to pick which you require to simulate again so that you don’t have to append the same requests again and again. 

Interleave Controller

This controller pickups one sampler per iteration and it is performed from top to bottom. For instance, we are having one interleave controller having 3 samplers names News Page and FAQ Page and Gump Page. It is running with 2 threads and a loop count of 5. So, a total of 10 requests will be executed per thread. 

Runtime Controller

This controller checks the execution of its samplers for the given time. If you define the run time as 10 seconds, then JMeter will run your tests for 10 seconds. 

Random Controller

It is the corresponding to the Interleave controller but rather than running from top to bottom, the random controller chooses any requests randomly. 

If Controller

It runs the requests only when a set of conditions is satisfied. 

Processor in JMeter

Processors are used for transforming the samplers. There are two kinds of processors. 

• Pre-processor are the processors which are implemented before sampler requests. If you want JMeter to verify all the links on the page and then recover the HTML. You can attach an HTML link parser that will parse links before a request is made to the server. 
• Post-Processor: If the request is presented to the server and is the requests send you an error then the post-processor should hold the further execution. 

If you pick Stop Test Now. This will halt the test if there will be any error in the response.

There is one more post-processor named debug processor which follows the values of variables that are in the requests. 

Also Read: 7 Best Performance Testing Tools To Utilize In 2021

Conclusion for Jmeter Tutorial

That sums Use JMeter tutorial to use performance and load testing so that your application is robust and can sand load without giving unexpected results. Use the wonderful elements of JMeter to give great reports to the stakeholders. 

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