Ryan Malloy
a1bd52788d
cursor.execute("SELECT 1 FROM systables WHERE tabid = 1")
cursor.fetchone() == (1,)
To my knowledge, this is the first time a pure-Python implementation
has read data from Informix without wrapping IBM's CSDK or JDBC.
Three breakthroughs in this commit:
1. Login PDU's database field is BROKEN. Passing a database name there
makes the server reject subsequent SQ_DBOPEN with sqlcode -759
("database not available"). JDBC always sends NULL in the login
PDU's database slot — we now do the same. The user-supplied database
opens via SQ_DBOPEN in _init_session.
2. Post-login session init dance: SQ_PROTOCOLS (8-byte feature mask
replayed verbatim from JDBC) → SQ_INFO with INFO_ENV + env vars
(48-byte PDU replayed verbatim — DBTEMP=/tmp, SUBQCACHESZ=10) →
SQ_DBOPEN. Without all three steps in this exact order, the server
silently ignores SELECTs.
3. SQ_DESCRIBE per-column block has 10 fields per column (not the
simple "name + type" my best-effort parser assumed): fieldIndex,
columnStartPos, columnType, columnExtendedId, ownerName,
extendedName, reference, alignment, sourceType, encodedLength.
The string table at the end is offset-indexed (fieldIndex points
into it), which is how JDBC handles disambiguation.
Cursor lifecycle implementation in cursors.py mirrors JDBC exactly:
PREPARE+NDESCRIBE+WANTDONE → DESCRIBE+DONE+COST+EOT
CURNAME+NFETCH(4096) → TUPLE*+DONE+COST+EOT
NFETCH(4096) → DONE+COST+EOT (drain)
CLOSE → EOT
RELEASE → EOT
Five round trips per SELECT — same as JDBC.
Module changes:
src/informix_db/connections.py — added _init_session(), _send_protocols(),
_send_dbopen(), _drain_to_eot(), _raise_sq_err(); login PDU now
forces database=None always; SQ_INFO PDU replayed verbatim from
JDBC capture (offsets-indexed env-var format too gnarly to derive
in MVP).
src/informix_db/cursors.py — full rewrite: real PDU builders for
PREPARE/CURNAME+NFETCH/NFETCH/CLOSE/RELEASE; tag-dispatched
response readers; cursor-name generator matching JDBC's "_ifxc"
convention.
src/informix_db/_resultset.py — proper SQ_DESCRIBE parser per
JDBC's receiveDescribe (USVER mode); offset-indexed string table
with name lookup by fieldIndex; ColumnInfo dataclass with raw
type-code preserved for null-flag extraction.
src/informix_db/_messages.py — added SQ_NDESCRIBE=22, SQ_WANTDONE=49.
Test coverage: 40 unit + 15 integration tests (7 smoke + 8 new SELECT)
= 55 total, all green, ruff clean. New tests cover:
- SELECT 1 returns (1,)
- cursor.description shape per PEP 249
- Multi-row INT SELECT
- Multi-column mixed types (INT + FLOAT)
- Iterator protocol (for row in cursor)
- fetchmany(n)
- Re-executing on same cursor resets state
- Two cursors on one connection (sequential)
Known gap: VARCHAR row decoding doesn't yet handle the variable-width
on-wire encoding correctly. Phase 2.x will address — for now NotImpl
errors surface raw bytes in the row tuple.
88 lines
2.7 KiB
Python
88 lines
2.7 KiB
Python
"""Shared pytest fixtures.
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The integration tests need a running Informix server on ``localhost:9088``
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with the default Developer Edition credentials (``informix`` / ``in4mix``
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on the ``sysmaster`` database). Run::
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docker compose -f tests/docker-compose.yml up -d
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before the integration suite. See ``docs/DECISION_LOG.md`` for the
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pinned image digest and credential rationale.
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Connection parameters are overridable via env vars
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(``IFX_HOST`` / ``IFX_PORT`` / ``IFX_USER`` / ``IFX_PASSWORD`` /
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``IFX_DATABASE`` / ``IFX_SERVER``) so the same suite runs against a
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non-default instance if you have one.
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"""
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from __future__ import annotations
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import os
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import socket
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from collections.abc import Iterator
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from typing import NamedTuple
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import pytest
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class ConnParams(NamedTuple):
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host: str
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port: int
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user: str
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password: str
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database: str
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server: str
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@pytest.fixture(scope="session")
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def conn_params() -> ConnParams:
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"""Connection parameters for the test Informix instance."""
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return ConnParams(
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host=os.environ.get("IFX_HOST", "127.0.0.1"),
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port=int(os.environ.get("IFX_PORT", "9088")),
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user=os.environ.get("IFX_USER", "informix"),
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password=os.environ.get("IFX_PASSWORD", "in4mix"),
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database=os.environ.get("IFX_DATABASE", "sysmaster"),
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server=os.environ.get("IFX_SERVER", "informix"),
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)
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@pytest.fixture(scope="session", autouse=True)
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def _check_integration_server(request: pytest.FixtureRequest, conn_params: ConnParams) -> None:
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"""Skip integration tests cleanly when the server isn't up.
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Avoids a sea of ``ConnectionRefusedError`` failures masking real bugs
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when the user runs the full suite without ``docker compose up``.
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"""
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if "integration" not in request.config.getoption("-m", default=""):
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return
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try:
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with socket.create_connection((conn_params.host, conn_params.port), timeout=2.0):
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return
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except OSError as e:
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pytest.skip(
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f"Informix server not reachable at {conn_params.host}:{conn_params.port} ({e}). "
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f"Start it with: docker compose -f tests/docker-compose.yml up -d"
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)
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@pytest.fixture
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def ifx_connection(conn_params: ConnParams) -> Iterator[object]:
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"""Open a fresh Informix connection for one test, then close it."""
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import informix_db
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conn = informix_db.connect(
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host=conn_params.host,
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port=conn_params.port,
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user=conn_params.user,
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password=conn_params.password,
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database=conn_params.database,
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server=conn_params.server,
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connect_timeout=10.0,
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read_timeout=10.0,
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)
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try:
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yield conn
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finally:
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conn.close()
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