Adonis Attachment

Appearance

Testing ​

Using db.assertHas() with attachment fields ​

INFO

db.assertHas() is available starting from @adonisjs/lucid v22.

When writing tests with AdonisJS, db.assertHas() compares values as stored in the database. Since attachment fields are persisted as JSON strings, passing an Attachment object directly will cause a type mismatch error:

Comparing two different types of values. Expected string but received number.

Use toDbString() to serialize the attachment exactly as it is stored in the database:

typescript
import { test } from '@japa/runner'

test('upload avatar', async ({ client, db }) => {
  const user = await User.create({ ... })

  // ... upload logic ...

  await db.assertHas('users', {
    id: user.id,
    avatar: user.avatar.toDbString(), // ✅ serializes to the JSON string stored in DB
  })
})

toDbString() returns the JSON string representation of the attachment, excluding internal fields like keyId. It matches exactly what is written to the database column.

TIP

toDbString() is available on both single attachment and each item in an attachments array.

typescript
// Single attachment
avatar: user.avatar.toDbString()

// Multiple attachments
documents: JSON.stringify(user.documents.map((d) => JSON.parse(d.toDbString())))

INFO

assert.deepEqual() on model instances continues to work without toDbString() since it compares the deserialized objects directly:

typescript
const fresh = await User.find(user.id)
assert.deepEqual(fresh.avatar, user.avatar) // ✅ works fine