What is the Test Plan Element Tree in JMeter?

A test plan element tree in JMeter is a tree diagram of test elements that represents the test plan structure.

Rules to remember when building a test plan tree in JMeter:

• Test Plan is the top level tree node.
• Thread Groups are second level tree nodes.
• Controllers are tree nodes, which can be placed under Thread Groups or Controllers themselves.
• Samplers are tree nodes, which can be placed under Thread Groups or Controllers.
• All other supporting elements are tree leaves, which can be placed under any tree nodes.

Here is a simplest JMeter test plan tree:

Test Plan 
   |- Thread Group 
         |- HTTP Request Sampler

Here is a more complex JMeter test plan tree:

Test Plan
   |- Summary Report Listener
   |- View Results in Table Listener
   |- Regular Expression Extractor PostProcessor
   |- BeanShell PreProcessor
   |- setUp Thread Group
   |     |- BeanShell Sampler
   |     |- JDBC Request Sampler
   |- Thread Group 
   |     |- BeanShell PreProcessor
   |     |- Regular Expression Extractor PostProcessor
   |     |- LDAP Request Sampler
   |     |- If Controller
   |     |     |- HTTP Request Sampler 
   |     |           |- BeanShell PreProcessor
   |     |           |- BeanShell PostProcessor
   |     |- Loop Controller
   |     |     |- HTTP Request Sampler 
   |     |     |     |- Regular Expression Extractor PostProcessor
   |     |     |- HTTP Request Sampler 
   |     |     |     |- Regular Expression Extractor PostProcessor
   |     |     |- HTTP Request Sampler 
   |     |           |- Regular Expression Extractor PostProcessor
   |     |- SMTP Request Sampler
   |- tearDown Thread Group
         |- BeanShell Sampler
     |- JDBC Request Sampler

⇒ JMeter Execution Order - General Rules

⇐ Types of Test Elements Supported in JMeter

⇑ JMeter Test Elements and Execution Order

⇑⇑ Apache JMeter Tutorials