> For the complete documentation index, see [llms.txt](https://atomico.gitbook.io/doc/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://atomico.gitbook.io/doc/api/testing/atomico-test-dom.md).

# atomico/test-dom

### fixture

function that allows to keep the render on a single node for each execution of `it`, the container will be unmounted at the end of each execution of `it`.

```javascript
import { html } from "atomico";
import { expect } from "@esm-bundle/chai";
import { fixture } from "atomico/test-dom";
import { Component } from "./component.js";

describe("my test", () => {
  it("my-component", async () => {
    const component = fixture(html`<${Component}>
        <span>content...</span>
    </${Component}>`);

    await component.updated;

    /** Test logic */
  });
});
```

This allows each fixture execution inside `it` to be related to the container used for the test, allowing you to fily test external DOM changes, example:

```javascript
import { html } from "atomico";
import { expect } from "@esm-bundle/chai";
import { fixture } from "atomico/test-dom";
import { Component } from "./component.js";


describe("my test", () => {
  it("my-component", async () => {
    // first instance of the render, it will return the component
    const component = fixture(html`<${Component}>
        <span>content...</span>
    </${Component}>`);

    await component.updated;
    
    // updates the content of the span tag of the first instance of the render
    fixture(html`<${Component}>
        <span>new content...</span>
    </${Component}>`);
    
    await component.updated;

    expect(
          component.querySelector("span").textContent
    ).to.equal("new content...");
  });
});
```


---

# 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 by asking a question.

Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters:

```
GET https://atomico.gitbook.io/doc/api/testing/atomico-test-dom.md?ask=<question>&goal=<user_goal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case.

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.