Implemented python tests with pytest (#790)

Currently the python tests act as scripts. A lot of output is generated to stdout which makes it very hard to figure out where problems were. Also if you want to run only a single test you basically need to comment out code in order to accomplish this.

This PR modifies the python tests to us the pytest python testing framework. This framework allows individual tests to be targeted via the command line, without touching the source code. It also suppressed stdout by default making the test output much easier to read. Also after the tests run it will provide a summary of what failed, what succeded, etc.


Co-authored-by: CommanderKeynes <andrewjackson947@gmail.coma>
Co-authored-by: Andrew Jackson <andrewjackson2988@gmail.com>

tests/python/utils.py

@@ -0,0 +1,60 @@
+from typing import Tuple
+import os
+import psutil
+import signal
+import time
+
+import psycopg2
+
+PGCAT_HOST = "127.0.0.1"
+PGCAT_PORT = "6432"
+
+def pgcat_start():
+    pg_cat_send_signal(signal.SIGTERM)
+    os.system("./target/debug/pgcat .circleci/pgcat.toml &")
+    time.sleep(2)
+
+
+def pg_cat_send_signal(signal: signal.Signals):
+    try:
+        for proc in psutil.process_iter(["pid", "name"]):
+            if "pgcat" == proc.name():
+                os.kill(proc.pid, signal)
+    except Exception as e:
+        # The process can be gone when we send this signal
+        print(e)
+
+    if signal == signal.SIGTERM:
+        # Returns 0 if pgcat process exists
+        time.sleep(2)
+        if not os.system('pgrep pgcat'):
+            raise Exception("pgcat not closed after SIGTERM")
+
+
+def connect_db(
+    autocommit: bool = True,
+    admin: bool = False,
+) -> Tuple[psycopg2.extensions.connection, psycopg2.extensions.cursor]:
+
+    if admin:
+        user = "admin_user"
+        password = "admin_pass"
+        db = "pgcat"
+    else:
+        user = "sharding_user"
+        password = "sharding_user"
+        db = "sharded_db"
+
+    conn = psycopg2.connect(
+        f"postgres://{user}:{password}@{PGCAT_HOST}:{PGCAT_PORT}/{db}?application_name=testing_pgcat",
+        connect_timeout=2,
+    )
+    conn.autocommit = autocommit
+    cur = conn.cursor()
+
+    return (conn, cur)
+
+
+def cleanup_conn(conn: psycopg2.extensions.connection, cur: psycopg2.extensions.cursor):
+    cur.close()
+    conn.close()