PURISTA

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Test a stream ​

Streams have two useful testing levels:

  • createStreamContextMock(...) for handler logic
  • createStreamTestHarness(...) for real runtime frames

Handler test ​

Use the context mock when you want to verify chunk and final payload logic directly.

ts
import { createStreamContextMock } from '@purista/core'

const mock = createStreamContextMock(searchUsersStreamBuilder, {
  payload: { query: 'ada' },
  parameter: {},
})

await searchUsersStreamBuilder.getStreamFunction()(
  mock.context,
  { query: 'ada' },
  {},
  mock.writer,
)

expect(mock.chunks).toStrictEqual([{ id: 'ada-1' }])
expect(mock.finalValue).toStrictEqual({ total: 1 })

Use this level when you want to verify:

  • chunk generation
  • final payload calculation
  • direct handler branching
  • emitted events or invokes inside the handler

Runtime test ​

Use the harness when you want to verify the real stream runtime behavior.

ts
import { createStreamTestHarness } from '@purista/core'

const harness = await createStreamTestHarness(userV1Service, searchUsersStreamBuilder)

try {
  const result = await harness.run({
    payload: { query: 'ada' },
    parameter: {},
  })

  expect(result.frames.length).toBeGreaterThan(0)
  expect(result.chunks).toStrictEqual([{ id: 'ada-1' }])
  expect(result.final).toStrictEqual({ total: 1 })
} finally {
  await harness.destroy()
}

Use this level when you want to verify:

  • before and after guards
  • frame emission through the event bridge
  • final runtime delivery