caption: testcase
created: 20230406161341763
modified: 20230406161341763
tags: Widgets
title: TestCaseWidget
type: text/vnd.tiddlywiki

! Introduction

The testcase widget creates an independent subwiki loaded with specified tiddlers and then renders a template that can display and render tiddlers from within the subwiki. This makes it possible to run independent tests that also serve as documentation examples.

! Content and Attributes

The content of the `<$testcase>` widget is not displayed but instead is scanned for <<.wlink DataWidget>> widgets that define the payload tiddlers to be included in the test case.

|!Attribute |!Description |
|<<.attr template>> |Optional title of the template used to display the testcase (defaults to $:/core/ui/testcases/DefaultTemplate) |

! State Handling

The `<$testcase>` widget sets the variable `transclusion` to a hash that reflects the names and values of all the payload tiddlers. This makes easier for test case templates to create unique state tiddler titles using the [[qualify Macro]] or QualifyWidget.

! Payload Tiddlers

The payload tiddlers are the tiddler values that are loaded into the subwiki that is created to run the tests. They are created via <<.wlink DataWidget>> widgets within the body of the `<$testcase>` widget.

! Test Case Templates

The test case template specified in the <<.attr template>> attribute can display and render tiddlers from the subwiki using the <<.wlink TestCaseTranscludeWidget>> and <<.wlink TestCaseViewWidget>> widgets.

The default test case template $:/core/ui/testcases/DefaultTemplate displays a split view with the source tiddlers on the left and the rendered tiddler titled `Output` on the right. It also displays the tiddler titled `Description` as the heading.

The `<$testcase>` widget assigns a value to the `transclusion` variable that depends on the combined values of all the payload tiddlers. This means that using the `<<qualify>>` macro within a test case template will generate a unique value for each of multiple test cases within the same tiddler.

! Test Case Variables

The `<$testcase>` widget also assigns a block of information about the subwiki in JSON format to a the variable `testcaseInfo`. It contains the following properties:

* ''tiddlers'': a hashmap by title of an array of all the field names of each tiddler in the subwiki (does not include shadow tiddlers unless they have been overridden)

! Test Case Conventions

The following conventions are used for test case tiddlers:

* `Description` contains a brief description of the test (rendered in inline mode)
* `Output` contains the tiddler text to be rendered. It can also reference other tiddlers
* `ExpectedResult` contains the HTML that should match the rendering of the tiddler `Output`

! Example

<$testcase>
<$data $tiddler="$:/core/ui/testcases/DefaultTemplate"/>
<$data $tiddler="$:/core/ui/testcases/DefaultTemplate/Source"/>
<$data title="Description" text="Simple example of a test case"/>
<$data title="Output" text="""<$testcase>
<$data title="Description" text="How to calculate 2 plus 2"/>
<$data title="Output" text="<$text text={{{ =2 =[add[2]] }}}/>"/>
</$testcase>
"""/>
</$testcase>