> For the complete documentation index, see [llms.txt](https://docs.testmace.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.testmace.com/node-types/assertion-node/contains.md).

# Contains

A **Contains assertion** can be used to check whether a substring is present in a string or whether a string equals to a regular expression.

This **Assertion** interface is as follows:

![](/files/-M4OLbmJPvI4d7bO1Rva)

The following **assertion** fields are shown in the screenshot:

* **Text** - the text to search the value in
* **Value** - the value that needs to be found
* The **Use negative statement** flag means using the opposite assertion result.
* The **Use value as Regular Expression** flag means that the value will be used as a regular expression template that the current value should match.

### Error Fixing

This **Assertion** doesn't have any error fixing algorithm.

### File Representation

The **assertion** is of the `contains` type in the file. The type description can be found in [Assertion file representation](https://docs.testmace.com/node-types/assertion-node#file-representation) documentation in the `#/definitions/CompareAssertion` definition.


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://docs.testmace.com/node-types/assertion-node/contains.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.