fix: Raise error when aexpect_helper doesn't work properly

When aexpect_helper does not work properly, the process will hang
without any log information. This fix checks the process status and
raises an error if the process terminates prematurely.

Signed-off-by: Yihuang Yu <[email protected]>

aexpect/client.py

@@ -193,9 +193,16 @@ def __init__(self, command=None, a_id=None, auto_close=False, echo=False,
             sub.stdin.write(f"{command}\n".encode(self.encoding))
             sub.stdin.flush()
             # Wait for the server to complete its initialization
-            while (f"Server {self.a_id} ready" not in
-                   sub.stdout.readline().decode(self.encoding, "ignore")):
-                pass
+            full_ouput = ""
+            pattern = f"Server {self.a_id} ready"
+            while True:
+                output = sub.stdout.readline().decode(self.encoding, "ignore")
+                if pattern in output:
+                    break
+                full_ouput += output
+                sub_status = sub.poll()
+                if sub_status is not None:
+                    raise ExpectProcessTerminatedError(pattern, sub_status, full_ouput)
 
         # Open the reading pipes
         if is_file_locked(self.lock_server_running_filename):
@@ -522,6 +529,7 @@ def __init__(self, command=None, a_id=None, auto_close=False, echo=False,
         :param encoding: Override text encoding (by default: autodetect by
                 locale.getpreferredencoding())
         """
+        self.tail_thread = None
         # Add a reader and a close hook
         self._add_reader("tail")
         self._add_close_hook(Tail._join_thread)
@@ -542,7 +550,6 @@ def __init__(self, command=None, a_id=None, auto_close=False, echo=False,
         self.output_prefix = output_prefix
 
         # Start the thread in the background
-        self.tail_thread = None
         if self.is_alive():
             if termination_func or output_func:
                 self._start_thread()