# Dynamic Suites

With TestBox's BDD syntax, it is possible to create suites dynamically; however, there are a few things to be aware of.

Setup for *dynamic* suites must be done in the pseudo-constructor (versus in `beforeAll()`). This is because `variables`-scoped variables set in `beforeAll()` are not available in the `describe` closure (even though they *are* available in `it` closures). This behavior can be explained by the execution sequence of a BDD bundle: When the bundle's `run()` method is called, it *collects* preliminary test data via `describe`s. *After* preliminary test data are collected, the `beforeAll()` runs, followed by the `describe` closures.

Additionally, care must be taken to pass data into the `it` closures, otherwise strange behavior will result (the values from the last loop iteration will be repeated in the body of each looped `it`).

## Example

The following bundle creates suites dynamically, by looping over test metadata.

```javascript
component
    extends="testbox.system.BaseSpec"
    hint="This is an example of a TestBox BDD test bundle containing dynamically-defined suites."
{

    /*
    * Need to do config for *dynamic* test suites here, in the
    * pseudo-constructor, versus in `beforeAll()`.
    */
    doDynamicSuiteConfig();

    /*
    * @hint This method is arbitrarily named, but it sets up 
    * metadata needed by the dynamic suites example. The setup
    * could have been done straight in the pseudo-constructor,
    * but it might be nice to organize it into such a method
    * as this.
    */
    function doDynamicSuiteConfig(){
        variables.dynamicSuiteConfig = ["foo","bar","baz"];
    }

    function run( testResults, testBox ){

        /*
        * @hint Dynamic Test Suites Example
        */
        // loop over test metadata
        for ( var thing in dynamicSuiteConfig ) {
            describe("Dynamic Suite #thing#", function(){
                // notice how data is passed into the it() closure:
                //  * data={ keyA=valueA, keyB=ValueB }
                //  * function( data )
                it( title=thing & "test", 
                    data={ thing=thing }, 
                    body=function( data ) {
                      var thing = data.thing;
                      expect( thing ).toBe( thing );
                });
            });
        }

    }

}
```