> ## Documentation Index
> Fetch the complete documentation index at: https://docs.sqd.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Testing pipes

> Test pipe logic against a mock portal, without network access

`@subsquid/pipes/testing` provides utilities for testing pipes end-to-end without hitting a real portal:

* `mockPortal(responses)` / `finalizedMockPortal(responses)`: spin up a local HTTP server that plays back scripted portal responses. Both resolve to `{ url, close() }`; pass `url` as the stream's `portal`.
* `readAll(stream)`: drain a stream into a flat array of data items.

For Solana there are no typed block builders yet; construct portal responses as raw block objects. Each response entry mirrors the portal wire format: a `header` plus the requested data items (`instructions`, `transactions`, etc.).

## Example (Vitest)

```ts expandable theme={"system"}
import { solanaInstructionDecoder, solanaPortalStream } from '@subsquid/pipes/solana'
import { MockPortal, MockResponse, mockPortal, readAll } from '@subsquid/pipes/testing'
import { beforeEach, describe, expect, it } from 'vitest'

import * as tokenProgram from './abi/tokenProgram/index.js'

const PORTAL_MOCK_RESPONSE: MockResponse[] = [
  {
    statusCode: 200,
    data: [
      {
        header: { number: 1, hash: 'ooooooooooooooooooooooooooooooooooooooooooo1', timestamp: 2000 },
        instructions: [
          {
            transactionIndex: 85,
            instructionAddress: [2, 0, 0],
            programId: 'TokenkegQfeZyiNwAJbNbGKPFXCWuBvf9Ss623VQ5DA',
            accounts: [
              '98vhGWL5CtK61KSKCJjJn2PVfkjzaw9QF6sRLptBWZvZ',
              '49gyyvxzf61PknHoTg2cFGYQCJRnUrC7Web8h8go7ceM',
              'EDMGEpKKGKS7nxpu1gjLmuHHWAmvLNy3BZWDxNC3nhAt',
            ],
            data: '3DXy58UDhJuu',
          },
        ],
      },
    ],
  },
]

describe('Solana pipe', () => {
  let portal: MockPortal

  beforeEach(async () => {
    await portal?.close()
    portal = await mockPortal(PORTAL_MOCK_RESPONSE)
  })

  it('decodes instructions from mock blocks', async () => {
    const stream = solanaPortalStream({
      id: 'test',
      portal: portal.url,
      logger: false,
      outputs: solanaInstructionDecoder({
        range: { from: 0, to: 1 },
        programId: 'TokenkegQfeZyiNwAJbNbGKPFXCWuBvf9Ss623VQ5DA',
        instructions: { transfers: tokenProgram.instructions.transfer },
      }).pipe((e) => e.transfers),
    })

    const res = await readAll(stream)

    expect(res).toHaveLength(1)
  })
})
```

## Mock response types

`mockPortal` accepts an array of scripted responses, played back in order:

```ts theme={"system"}
type MockResponse =
  | { statusCode: 204 }                                                  // empty response
  | { statusCode: 200, data: [...], head?: { finalized?, latest? } }     // data blocks
  | { statusCode: 409, data: { previousBlocks: [...] } }                 // fork signal
  | { statusCode: 500 | 503 }                                            // server error
```

The 409 variant lets you test [fork handling](../architecture-deep-dives/fork-handling) deterministically, and 500/503 let you exercise retry behavior.