pytest-adbc-replay

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Record/replay testing for ADBC database queries, as a pytest plugin.

What / Why

Works like VCR.py and pytest-recording: the first run records live queries to cassette files on disk, subsequent runs replay from those cassettes. CI tests pass with no live warehouse connection, and query changes are visible as plain diffs in pull requests (.sql files are human-readable and committed to version control).

Installation

pip install pytest-adbc-replay

Quick Start

For this example we'll use the DuckDB ADBC driver (no credentials needed):

pip install adbc-driver-duckdb

Mocking is flexible enough to use with any ADBC driver.

pyproject.toml — tell the plugin which drivers to intercept:

[tool.pytest.ini_options]
adbc_auto_patch = ["adbc_driver_duckdb.dbapi"]

The value is the Python module path where connect() lives — for all standard ADBC drivers this is adbc_driver_<name>.dbapi.

test_example.py — mark each test and call connect() normally:

import adbc_driver_duckdb.dbapi as duckdb
import pytest


@pytest.mark.adbc_cassette("my_query")
def test_my_query():
    conn = duckdb.connect()
    with conn.cursor() as cur:
        cur.execute("SELECT 42 AS answer")
        assert cur.fetchone() == (42,)

No conftest.py needed. The plugin intercepts duckdb.connect() automatically for tests decorated with @pytest.mark.adbc_cassette.

Record cassettes on the first run:

pytest --adbc-record=once

Replay from cassettes (default — no flag needed):

pytest

Cassette Layout

tests/cassettes/
└── my_query/
    └── adbc_driver_duckdb.dbapi/
        ├── 000.sql      # human-readable normalised SQL
        ├── 000.arrow    # Arrow IPC result with schema metadata
        └── 000.json     # parameters and driver options (null when absent)

Commit the cassettes to version control — any changes appear as diffs in pull requests.

Configuration Reference

Minimal pyproject.toml snippet:

[tool.pytest.ini_options]
adbc_cassette_dir = "tests/cassettes"
adbc_record_mode = "none"
adbc_dialect = []  # e.g. ["adbc_driver_snowflake.dbapi: snowflake", "adbc_driver_duckdb.dbapi: duckdb"]
adbc_auto_patch = []  # e.g. ["adbc_driver_duckdb.dbapi", "adbc_driver_snowflake.dbapi"]
adbc_scrub_keys = []  # e.g. ["token password", "adbc_driver_snowflake: account_id"]

Record Modes

Scrubbing Sensitive Values

To keep credentials out of cassette files, list parameter key names in adbc_scrub_keys:

[tool.pytest.ini_options]
adbc_scrub_keys = ["token password api_key"]

Matched values become REDACTED in the .json cassette file. Per-driver form:

adbc_scrub_keys = [
    "token",
    "adbc_driver_snowflake: account_id warehouse",
]

For custom scrubbing logic, override the adbc_scrubber fixture in your conftest.py:

import pytest


@pytest.fixture(scope="session")
def adbc_scrubber():
    def scrub(params: dict | None, driver_name: str) -> dict | None:
        if not isinstance(params, dict):
            return params
        return {k: "REDACTED" if k.endswith("_key") else v for k, v in params.items()}

    return scrub

Config scrubbing runs first; the fixture callable receives the already-config-scrubbed params.

Advanced

adbc_param_serialisers is a session-scoped fixture for registering custom parameter serialisers for types not handled by default.

Full reference documentation: https://s-layer.github.io/pytest-adbc-replay

License

BSD-3-Clause