From e2e73cbf5dd2eb565da3ea45a8aa6d061bca0a1d Mon Sep 17 00:00:00 2001
From: Jan Vlcinsky <jan.vlcinsky@tamtamresearch.com>
Date: Thu, 26 Apr 2018 22:47:11 +0200
Subject: [PATCH] tests/test_transactions.py refactored

---
 tests/conftest.py          | 47 ++++++++++++++++++++++++++
 tests/test_transactions.py | 67 +++++++++++++++++++++++++-------------
 tox.ini                    |  4 +--
 3 files changed, 94 insertions(+), 24 deletions(-)
 create mode 100644 tests/conftest.py

diff --git a/tests/conftest.py b/tests/conftest.py
new file mode 100644
index 0000000..37128f2
--- /dev/null
+++ b/tests/conftest.py
@@ -0,0 +1,47 @@
+"""Shared pytest fixtures.
+
+"""
+import pytest
+
+import records
+
+
+@pytest.fixture(params=[
+    # request: (sql_url_id, sql_url_template)
+
+    ('sqlite_memory', 'sqlite:///:memory:'),
+    ('sqlite_file', 'sqlite:///{dbfile}'),
+    # ('psql', 'postgresql://records:records@localhost/records')
+],
+    ids=lambda r: r[0])
+def db(request, tmpdir):
+    """Instance of `records.Database(dburl)`
+
+    Ensure, it gets closed after being used in a test or fixture.
+
+    Parametrized with (sql_url_id, sql_url_template) tuple.
+    If `sql_url_template` contains `{dbfile}` it is replaced with path to a
+    temporary file.
+
+    Feel free to parametrize for other databases and experiment with them.
+    """
+    id, url = request.param
+    # replace {dbfile} in url with temporary db file path
+    url = url.format(dbfile=str(tmpdir / "db.sqlite"))
+    db = records.Database(url)
+    yield db  # providing fixture value for a test case
+    # tear_down
+    db.close()
+
+
+@pytest.fixture
+def foo_table(db):
+    """Database with table `foo` created
+
+    tear_down drops the table.
+
+    Typically applied by `@pytest.mark.usefixtures('foo_table')`
+    """
+    db.query('CREATE TABLE foo (a integer)')
+    yield
+    db.query('DROP TABLE foo')
diff --git a/tests/test_transactions.py b/tests/test_transactions.py
index f2d5e92..c9255b3 100644
--- a/tests/test_transactions.py
+++ b/tests/test_transactions.py
@@ -1,19 +1,43 @@
+"""Test manipulating database table in various transaction scenarios.
+
+Varying conditions:
+
+- db for different database backends (see `db` fixture)
+- query run via
+
+    - `db=records.Database(); db.query()
+    - `conn=db.get_connection(); conn.query()`
+
+- transaction
+    - not used at all
+    - used and created in different ways
+    - transaction succeeds
+    - transaction fails or raise
+"""
 import pytest
 
-import records
 
-db = records.Database('sqlite:///:memory:')
+@pytest.mark.usefixtures('foo_table')
+def test_plain_db(db):
+    """Manipulate database by `db.query` without transactions.
+    """
+    db.query('INSERT INTO foo VALUES (42)')
+    db.query('INSERT INTO foo VALUES (43)')
+    assert db.query('SELECT count(*) AS n FROM foo')[0].n == 2
 
 
-@pytest.fixture
-def table_setup(request):
-    db.query('CREATE TABLE foo (a integer)')
-    def drop_table():
-        db.query('DROP TABLE foo')
-    request.addfinalizer(drop_table)
+@pytest.mark.usefixtures('foo_table')
+def test_plain_conn(db):
+    """Manipulate database by `conn.query` without transactions.
+    """
+    conn = db.get_connection()
+    conn.query('INSERT INTO foo VALUES (42)')
+    conn.query('INSERT INTO foo VALUES (43)')
+    assert conn.query('SELECT count(*) AS n FROM foo')[0].n == 2
 
 
-def test_failing_transaction_self_managed(table_setup):
+@pytest.mark.usefixtures('foo_table')
+def test_failing_transaction_self_managed(db):
     conn = db.get_connection()
     tx = conn.transaction()
     try:
@@ -22,14 +46,15 @@ def test_failing_transaction_self_managed(table_setup):
         raise ValueError()
         tx.commit()
         conn.query('INSERT INTO foo VALUES (44)')
-    except:
+    except ValueError:
         tx.rollback()
     finally:
         conn.close()
         assert db.query('SELECT count(*) AS n FROM foo')[0].n == 0
 
 
-def test_failing_transaction(table_setup):
+@pytest.mark.usefixtures('foo_table')
+def test_failing_transaction(db):
     with db.transaction() as conn:
         conn.query('INSERT INTO foo VALUES (42)')
         conn.query('INSERT INTO foo VALUES (43)')
@@ -38,21 +63,19 @@ def test_failing_transaction(table_setup):
     assert db.query('SELECT count(*) AS n FROM foo')[0].n == 0
 
 
-def test_passing_transaction_self_managed(table_setup):
+@pytest.mark.usefixtures('foo_table')
+def test_passing_transaction_self_managed(db):
     conn = db.get_connection()
     tx = conn.transaction()
-    try:
-        conn.query('INSERT INTO foo VALUES (42)')
-        conn.query('INSERT INTO foo VALUES (43)')
-        tx.commit()
-    except:
-        tx.rollback()
-    finally:
-        conn.close()
-        assert db.query('SELECT count(*) AS n FROM foo')[0].n == 2
+    conn.query('INSERT INTO foo VALUES (42)')
+    conn.query('INSERT INTO foo VALUES (43)')
+    tx.commit()
+    conn.close()
+    assert db.query('SELECT count(*) AS n FROM foo')[0].n == 2
 
 
-def test_passing_transaction(table_setup):
+@pytest.mark.usefixtures('foo_table')
+def test_passing_transaction(db):
     with db.transaction() as conn:
         conn.query('INSERT INTO foo VALUES (42)')
         conn.query('INSERT INTO foo VALUES (43)')
diff --git a/tox.ini b/tox.ini
index df57c06..4e93a8b 100644
--- a/tox.ini
+++ b/tox.ini
@@ -3,11 +3,11 @@
 # and then run "tox" from this directory.
 
 [tox]
-envlist = py27, py33, py34, py35, py36
+envlist = py27, py34, py35, py36
 
 [testenv]
 commands =
     pytest tests
 deps =
     pytest
-
+    # psycopg2-binary