> For the complete documentation index, see [llms.txt](https://testbox.ortusbooks.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://testbox.ortusbooks.com/digging-deeper/expectations.md).

# Expectations

TestBox allows you to create BDD expectations with our expectations and matcher API DSL. You start by calling our `expect()` method, usually with an **actual** value you would like to test. You then concatenate the expectation of that actual value/function to a result or what we call a matcher. You can also concatenate matchers (as of v2.1.0) so you can provide multiple matching expectations to a single value.

```javascript
expect( 43 ).toBe( 42 );
expect( () => calculator.add(2,2) ).toThrow();
```


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