using-temporary-files
v2.2.1
Published
usingTemporaryFiles() - a utility for testing code that accesses the file system
Downloads
113
Readme
usingTemporaryFiles()
A utility for working with tests that need to write to / read from the file system.
It creates a temporary directory, copies the specified files into it, provides some functions for working with files in the temporary directory, and then deletes the directory when the callback returns or an error occurs.
Installation
npm install --save-dev using-temporary-files
Usage
import { usingTemporaryFiles } from "using-temporary-files";
await usingTemporaryFiles(async ({ path, add, addDirectory, remove }) => {
path("."); // full path to the temporary directory
path("file.txt"); // full path to a particular file
await add("file.txt", "content"); // add a file
const text = await read("file.txt" /*, encoding (optional) */); // read the contents of a file
await addDirectory("dir"); // add a directory
await remove("file.txt"); // remove a file
});
Background
This code was extracted from Counterfact so that it can be
used in other projects. The original function was named withTemporaryFiles()
. It was renamed to
usingTemporaryFiles
so that it resembles the
Explicit Resource Management proposal.
To understand how it's used in practice, see the tests in Counterfact
Note that until I get around to updating Counterfact to use this package, the API for withTemporaryFiles()
has a few minor differences. Mainly extra arguments that we can do without.
FAQ
Accessing the file system is slow. Isn't it better to mock the file system?
Yes, it is. And that's what I do most of the time. But it's good to have a couple of end-to-end tests that exercise the real file system. This utility makes it easier to write those tests.