JMeter is a testing tool to simulate thousands of users. It uses Java Threads for this.
Configure a Test Plan
In JMeter the components of a test are organized in a tree, where each component has a scope that determines to what other components it has access to.
Test Plan
Test Plan is the root element of a test, where all overall settings are specified and all the other elements are contained.
It allows us to:
- Define variables to the entire test.
- There we can set to run Thread Groups consecutively, instead of parallel.
- We may run tearDown Thread Groups. They run at the end of the test, after a graceful shutdown of the main Threads. They won’t be run if the test is forcibly stopped.
- If we select Functional Test Mode, JMeter will save information from the server responses to result files. Beware, as this files grow quickly and they impact performance. Only for small tests.
- We may add jar files or directories to classpath, so they will load just for the test script.
Thread Groups
They’re the entry point of a test and controls the number of threads (users) JMeter will use to execute a test. We also have setUp and tearDown Thread Groups.
We may:
- Set the number of users and the time it will take to create them. This creation can be delayed until they’re needed.
Configuration Elements
They’re used to set up default configurations and variables for later use by other components. They can be placed under any other component.
They are classified into:
- elements that allows us to set variables: CSV Data Set Config, Counter or Random Variable.
- elements that allows us to define a Configuration: JDBC Connection Configuration, KeyStore Configuration, Login Config Element.
- managers that allow us to manage configuration params: HTTP Header Manager, HTTP Cookie Manager, HTTP Cache Manager.
- default configuration elements: HTTP Request Defaults, FTP Request Defaults, Java Request Defaults.
The most common used are:
- CSV Data Set Config used to read the content of a CSV file and turn it into variables.
- HTTP Header Manager allows us to add or override HTTP Request Headers.
- HTTP Cookie Manager For each user, it stores and sends a cookie like a browser; Allows to manually add a cookie that will be shared by all users.
- HTTP Cache Manager Adds caching functionality to HTTP Request. Each user has its own cache.
- User defined variables allows you to define a set of variables. They’re processed once at the start of the test and are shared between old thread groups.
He created an HTTP Request Defaults and added the IP and port number, so he doesn’t need to repeate this at every component.