Move test of parse_args() as a Python unit test

So as to isolate the test on --help in the doctest to helper forthcoming
changes.

Author: dlax

tests/test_cli.py

@@ -0,0 +1,44 @@
+from pgactivity import cli
+
+
+def test_parser() -> None:
+    parser = cli.get_parser()
+    ns = parser.parse_args(
+        ["--no-db-size", "-w", "-p", "5433", "--no-pid", "--no-app-name"]
+    )
+    assert vars(ns) == {
+        "profile": None,
+        "blocksize": 4096,
+        "rds": False,
+        "output": None,
+        "dbsize": False,
+        "tempfiles": True,
+        "walreceiver": True,
+        "wrap_query": True,
+        "durationmode": "1",
+        "minduration": 0,
+        "filters": [],
+        "debug_file": None,
+        "help": False,
+        "connection_string": "",
+        "host": None,
+        "port": "5433",
+        "username": None,
+        "dbname": None,
+        "pid": False,
+        "database": True,
+        "user": True,
+        "client": True,
+        "cpu": True,
+        "mem": True,
+        "read": True,
+        "write": True,
+        "time": True,
+        "wait": True,
+        "appname": False,
+        "header_show_instance": None,
+        "header_show_system": None,
+        "header_show_workers": None,
+        "hide_queries_in_logs": False,
+        "refresh": 2,
+    }

tests/test_cli.txt

@@ -78,7 +78,3 @@ an URI as described in the PostgreSQL documentation. The parsing is delegated
 to the libpq: different versions of the client library may support different
 formats or parameters (for example, connection URIs are only supported from
 libpq 9.2).
-
->>> ns = parser.parse_args(["--no-db-size", "-w", "-p", "5433", "--no-pid", "--no-app-name"])
->>> vars(ns)
-{'profile': None, 'blocksize': 4096, 'rds': False, 'output': None, 'dbsize': False, 'tempfiles': True, 'walreceiver': True, 'wrap_query': True, 'durationmode': '1', 'minduration': 0, 'filters': [], 'debug_file': None, 'help': False, 'connection_string': '', 'host': None, 'port': '5433', 'username': None, 'dbname': None, 'pid': False, 'database': True, 'user': True, 'client': True, 'cpu': True, 'mem': True, 'read': True, 'write': True, 'time': True, 'wait': True, 'appname': False, 'header_show_instance': None, 'header_show_system': None, 'header_show_workers': None, 'hide_queries_in_logs': False, 'refresh': 2}