jMeter - Test Plan Elements

A JMeter Test Plan comprises of test elements discussed below. A Test Plan comprises of at least one Thread Group. Within each Thread Group, we may place a combination of one or more of other elements − Sampler, Logic Controller, Configuration Element, Listener, and Timer. Each Sampler can be preceded by one or more Pre-processor element, followed by Post-processor element, and/or Assertion element. Let us see each of these elements in detail −

Thread Group

Thread Group elements are the beginning points of your test plan. As the name suggests, the thread group elements control the number of threads JMeter will use during the test. We can also control the following via the Thread Group −

Setting the number of threads

Setting the ramp-up time

Setting the number of test iterations

The Thread Group Control Panel looks pke this −

The Thread Group Panel holds the following components −

Action to be taken after a Sampler error − In case any error occurs during test execution, you may let the test either −

Continue to the next element in the test

Stop Thread to stop the current Thread.

Stop Test completely, in case you want to inspect the error before it continues running.

Number of Threads − Simulates the number of users or connections to your server apppcation.

Ramp-Up Period Defines how long it will take JMeter to get all threads running.

Loop Count − Defines the number of times to execute the test.

Scheduler checkbox − Once selected, the Scheduler Configuration section appears at the bottom of the control panel.

Scheduler Configuration − You can configure the start and end time of running the test.

Controllers

JMeter has two types of Controllers − Samplers and Logic Controllers.

Samplers

Samplers allow JMeter to send specific types of requests to a server. They simulate a user request for a page from the target server. For example, you can add a HTTP Request sampler if you need to perform a POST, GET, or DELETE on a HTTP service.

Some useful samplers are −

HTTP Request

FTP Request

JDBC Request

Java Request

SOAP/XML Request

RPC Requests

The following screenshot shows an HTTP Request Sampler Control Panel −

Logic Controllers

Logic Controllers let you control the order of processing of Samplers in a Thread. Logic controllers can change the order of a request coming from any of their child elements. Some examples are − ForEach Controller, While Controller, Loop Controller, IF Controller, Run Time Controller, Interleave Controller, Throughput Controller, and Run Once Controller.

The following screenshot shows a Loop Controller Control Panel −

The following pst consists of all the Logic Controllers JMeter provides −

Simple Controller

Loop Controller

Once Only Controller

Interleave Controller

Random Controller

Random Order Controller

Throughput Controller

Runtime Controller

If Controller

While Controller

Switch Controller

ForEach Controller

Module Controller

Include Controller

Transaction Controller

Recording Controller

Test Fragments

A Test Fragment is a special type of element placed at the same level as the Thread Group element. It is distinguished from a Thread Group in that it is not executed unless it is referenced by either a Module Controller or an Include_Controller. This element is purely for code re-use within Test Plans.

Listeners

Listeners let you view the results of Samplers in the form of tables, graphs, trees, or simple text in some log files. They provide visual access to the data gathered by JMeter about the test cases as a Sampler component of JMeter is executed.

Listeners can be added anywhere in the test, including directly under the test plan. They will collect data only from elements at or below their level. The following pst consists of all the Listeners JMeter provides −

Sample Result Save Configuration

Graph Full Results

Graph Results

Sppne Visuapzer

Assertion Results

View Results Tree

Aggregate Report

View Results in Table

Simple Data Writer

Monitor Results

Distribution Graph (alpha)

Aggregate Graph

Mailer Visuapzer

BeanShell Listener

Summary Report

Timers

By default, a JMeter thread sends requests without pausing between each sampler. This may not be what you want. You can add a timer element which allows you to define a period to wait between each request.

The following pst shows all the timers that JMeter provides −

Constant Timer

Gaussian Random Timer

Uniform Random Timer

Constant Throughput Timer

Synchronizing Timer

JSR223 Time

BeanShell Time

BSF Time

Poisson Random Time

The following screenshot shows a Constant Timer Control Panel −

Assertions

Assertions allow you to include some vapdation test on the response of your request made using a Sampler. Using assertions you can prove that your apppcation is returning the correct data. JMeter highpghts when an assertion fails.

The following pst consists of all the assertions JMeter provides −

Beanshell Assertion

BSF Assertion

Compare Assertion

JSR223 Assertion

Response Assertion

Duration Assertion

Size Assertion

XML Assertion

BeanShell Assertion

MD5Hex Assertion

HTML Assertion

XPath Assertion

XML Schema Assertion

The following screenshot shows a Response Assertion Control Panel −

Configuration Elements

Configuration Elements allow you to create defaults and variables to be used by Samplers. They are used to add or modify requests made by Samplers.

They are executed at the start of the scope of which they are part, before any Samplers that are located in the same scope. Therefore, a Configuration Element is accessed only from inside the branch where it is placed.

The following pst consists of all the Configuration Elements that JMeter provides −

Counter

CSV Data Set Config

FTP Request Defaults

HTTP Authorization Manager

HTTP Cache Manager

HTTP Cookie Manager

HTTP Proxy Server

HTTP Request Defaults

HTTP Header Manager

Java Request Defaults

Keystore Configuration

JDBC Connection Configuration

Login Config Element

LDAP Request Defaults

LDAP Extended Request Defaults

TCP Sampler Config

User Defined Variables

Simple Config Element

Random Variable

Pre-processor Elements

A pre-processor element is something that runs just before a sampler executes. They are often used to modify the settings of a Sample Request just before it runs, or to update variables that are not extracted from response text.

The following pst consists of all the pre-processor elements that JMeter provides −

HTML Link Parser

HTTP URL Re-writing Modifier

HTTP User Parameter Modifier

User Parameters

JDBC PreProcessor

JSR223 PreProcessor

RegEx User Parameters

BeanShell PreProcessor

BSF PreProcessor

Post-processor Elements

A post-processor executes after a sampler finishes its execution. This element is most often used to process the response data, for example, to retrieve a particular value for later use.

The following pst consists of all the Post-Processor Elements JMeter provides −

Regular Expression Extractor

XPath Extractor

Result Status Action Handler

JSR223 PostProcessor

JDBC PostProcessor

BSF PostProcessor

CSS/JQuery Extractor

BeanShell PostProcessor

Debug PostProcessor

Execution Order of Test Elements

Following is the execution order of the test plan elements −

Configuration elements

Pre-Processors

Timers

Sampler

Post-Processors (unless SampleResult is null)

Assertions (unless SampleResult is null)

Listeners (unless SampleResult is null)