# 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:

![](https://1550208191-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LYfhIaTTw23Sf3L5jfe%2F-M4OKquMmkk-bwr0AM-W%2F-M4OLbmJPvI4d7bO1Rva%2Fimage.png?alt=media\&token=e6a0a45d-1fe0-466c-8dd4-43d3575f0f60)

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.