Add integ tests for the ping feature

TODO: get the exit code test to pass

tests/features/basic_commands.feature

@@ -51,6 +51,14 @@ Feature: run the cli,
       When we list databases
       then we see list of databases
 
+  Scenario: ping databases
+      When we ping the database
+      then we get a pong response
+
+  Scenario: ping databases
+      When we ping the database
+      then we exit with 0
+
   Scenario: run the cli with --username
     When we launch dbcli using --username
       and we send "\?" command

tests/features/steps/basic_commands.py

@@ -26,6 +26,23 @@ def step_see_list_databases(context):
     context.cmd_output = None
 
 
+@when("we ping the database")
+def step_ping_database(context):
+    cmd = ["pgcli", "--ping"]
+    context.cmd_output = subprocess.check_output(cmd, cwd=context.package_root)
+
+
+@then("we get a pong response")
+def step_get_pong_response(context):
+    assert context.cmd_output.strip() == b"PONG", f"Output was {context.cmd_output}"
+
+
+@then("we exit with 0")
+def step_exit_with_0(context):
+    context.cli.close()
+    assert context.cli.exitstatus == 0, f"Exit code was {context.cli.exitstatus}"
+
+
 @when("we run dbcli")
 def step_run_cli(context):
     wrappers.run_cli(context)