pytest fixture and readme fixes.

Author: michelp

.github/workflows/wheels.yml

@@ -24,7 +24,6 @@ jobs:
       - name: Build wheels
         run: python -m cibuildwheel --output-dir wheelhouse
         env:
-          CIBW_ENVIRONMENT:
           CIBW_BEFORE_ALL_LINUX: ${{ format('sh tools/install_pg.sh {0}', github.ref) }}
       - uses: actions/upload-artifact@v2
         with:

README.md

@@ -25,7 +25,8 @@ $ pip install postgresql-wheel
 ```
 
 Postgres binaries in the package can be found in the directory pointed
-to by the `postgresql.pg_bin` global variable.  `initdb` and `pg_ctl`
+to by the `postgresql.pg_bin` global variable.  Function wrappers
+around all of the postgres binary programs, like `initdb` and `pg_ctl`
 functions are provided for convenience:
 
 ```py3
@@ -40,6 +41,26 @@ functions are provided for convenience:
 >>>     print(q.fetchall())
 ...
 [('PostgreSQL 13.4 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 8.3.1 20190311 (Red Hat 8.3.1-3), 64-bit',)]
+>>> pg_ctl('-D testdatabase stop)
 
 ```
 
+For the purposes of testing, convenience functions are provided for
+setting up and tearing down databases:
+
+```py3
+>>> pgdata, con_str = postgresql.setup()
+>>> postgresql.psql(f'-h {con_str} -c "select version()"')
+>>> postgresql.teardown(pgdata)
+```
+
+There is also a pytest fixture called `tmp_postgres` that returns a
+new connection string to a temporary databse local domain socket, and
+can be used in a pytest:
+
+```py3
+>>> from postgresql import tmp_postgres
+>>> def test_foo(tmp_postgres):
+...    postgresql.psql(f'-h {tmp_postgres} -c "select version()")
+```
+

postgresql/__init__.py

@@ -1,6 +1,11 @@
 import sys
+import os
+import shutil
 from subprocess import check_output
 from pathlib import Path
+from tempfile import TemporaryDirectory
+from time import sleep
+import pytest
 
 pg_bin = Path(__file__).parent / "bin"
 
@@ -27,6 +32,36 @@ def f(cmdline):
     setattr(this, p, prog(p))
 
 
+def setup(pgdata=None, log="db_test.log", user="postgres"):
+    if pgdata is None:
+        pgdata = TemporaryDirectory().name
+
+    log = Path(log)
+    try:
+        log.unlink()
+    except FileNotFoundError:
+        pass
+
+    initdb(f"-D {pgdata} --auth-local=trust --no-sync -U postgres")
+    pg_ctl(f'-D {pgdata} -o "-k {pgdata} -h \\"\\"" -l {log} start')
+    sleep(3)
+    con_str = f"host={pgdata} user={user}"
+    return pgdata, con_str
+
+
+def teardown(pgdata):
+    msg = pg_ctl(f"-D {pgdata} stop")
+    shutil.rmtree(pgdata)
+    return msg
+
+
+@pytest.fixture
+def tmp_postgres():
+    pgdata, con_str = setup()
+    yield con_str
+    teardown(pgdata)
+
+
 from . import _version
 
 __version__ = _version.get_versions()["version"]

setup.py

@@ -21,6 +21,7 @@ def package_files(directory):
     packages=["postgresql"],
     package_data={"postgresql": package_files("postgresql")},
     setup_requires=["cffi"],
+    install_requires=["pytest"],
     cffi_modules=["postgresql/build.py:ffibuilder"],
     python_requires=">=3.7,<3.10",
 )

tests/__init__.py

@@ -1 +1,6 @@
 import postgresql
+
+
+def test_setup_teardown():
+    pgdata, conn = postgresql.setup()
+    postgresql.teardown(pgdata)