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

# Testing & schema export

> An in-process test client and a schema-export CLI.

## Test client

`GraphQLTestClient` runs operations in-process against a schema — no transport
required — and collects subscription streams.

```python theme={null}
from fastql import GraphQLTestClient

client = GraphQLTestClient(schema)

result = await client.execute("{ ping }")
assert result.errors == []

async for event in client.subscribe("subscription { counter(to: 2) }"):
    print(event.data)
```

`execute` covers queries and mutations and accepts `variable_values`, `context`, and
`operation_name`; `subscribe` yields one `ExecutionResult` per event.

## Schema export CLI

Export a schema as SDL or introspection JSON from the command line:

```bash theme={null}
python -m fastql export-schema myapp:schema                 # SDL to stdout
python -m fastql export-schema myapp:schema --format json   # introspection JSON
python -m fastql export-schema myapp:schema --output schema.graphql
```

The target is a `module:attribute` path to a built `Schema`. `--format` is `sdl`
(default) or `json`; `--output` writes to a file instead of stdout. An unresolvable
target exits non-zero.