Testing fastify/multipart file upload without form-data library

[shania-g]

Hello there.

I would like to add testing to my endpoint which uses fastify/multipart to accept a file upload and then writes it to the filesystem.

In the testing directory of this repository I saw that popular form-data library is used, however, I think this can also be achieved without it?

What I have come up with, but for some reason does not work:

const __filename = fileURLToPath(import.meta.url)
const __dirname = dirname(__filename)

const filePath = join(__dirname, '../example.jpg')

describe('POST /asset', () => {
        it('should return 201 when the payload is valid', async () => {
            const rawData = readFileSync(filePath, 'binary')

            const body = new FormData()
            const blob = new Blob([rawData])

            body.set('file', blob, 'example.jpg')

            const res = await app.inject({
                method: 'POST',
                url: '/asset',
                payload: {
                    file: body.get('file')
                }
            })

            assert.deepStrictEqual(res.statusCode, 201)
        })
    })

However, this gives me the following error:

{"statusCode":400,"code":"FST_ERR_VALIDATION","error":"Bad Request","message":"body/file should be a file"}

This is my route definition (I do not think this is relevant, but maybe it could be):

fastify.post(
        '/',
        {
            schema: {
                consumes: ['multipart/form-data'],
                body: {
                    type: 'object',
                    required: ['file'],
                    properties: {
                        file: { isFile: true }
                    }
                }
            }
        },
        createAsset
    )

Is there any way to make this testing work?

Thank you very much in advance.

[climba03003]

It doesn't work because you didn't provide the proper header.

[shania-g]

It doesn't work because you didn't provide the proper header.

You mean for the inject I should include multipart/form-data as a header?

[climba03003]

see fastify/light-my-request#286

If you don't want to use form-data, you need to wait until the above PR landed and published.
Otherwise form-data package should be the only reliable choice.

You may copy the form-data.js in that PR and use it to provide Content-Type header and stream payload.