test: add coverage for QThread

pyproject.toml

@@ -234,13 +234,14 @@ exclude_also = [
     "def _link_splitters",
     "def draw_mode",
     "QtWidgets.QApplication(sys.argv)",
+    "QtWidgets.QMessageBox.question",
     "if not qapp:",
     "if execute is None:",
     "qapp.exec()",
     "if __name__ == __main__:",
     "except varname.VarnameRetrievingError:",
     "if TYPE_CHECKING:",
-    "QtCore.QThread",
+    "def _wrapped_for_coverage",
 ]
 
 [tool.mypy]

src/erlab/interactive/imagetool/manager.py

@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+import functools
 import os
 import pickle
 import socket
@@ -42,13 +43,25 @@ class ItoolManagerParseError(Exception):
     """Raised when the data received from the client cannot be parsed."""
 
 
+def _coverage_resolve_trace(fn):
+    # https://github.com/nedbat/coveragepy/issues/686#issuecomment-634932753
+    @functools.wraps(fn)
+    def _wrapped_for_coverage(*args, **kwargs):
+        if threading._trace_hook:
+            sys.settrace(threading._trace_hook)
+        fn(*args, **kwargs)
+
+    return _wrapped_for_coverage
+
+
 class _ManagerServer(QtCore.QThread):
     sigReceived = QtCore.Signal(list, dict)
 
     def __init__(self):
         super().__init__()
         self.stopped = threading.Event()
 
+    @_coverage_resolve_trace
     def run(self):
         self.stopped.clear()
         soc = socket.socket()