From 96de1a261a6eeac4319eb27302c4a62975ef8f6e Mon Sep 17 00:00:00 2001
From: Talley Lambert <talley.lambert@gmail.com>
Date: Sun, 20 Feb 2022 11:25:10 -0500
Subject: [PATCH] add signals_blocked util (#69)

---
 src/superqt/utils/__init__.py | 11 +++++++----
 src/superqt/utils/_misc.py    | 15 +++++++++++++++
 tests/test_utils.py           | 29 +++++++++++++++++++++++++++++
 3 files changed, 51 insertions(+), 4 deletions(-)
 create mode 100644 src/superqt/utils/_misc.py
 create mode 100644 tests/test_utils.py

diff --git a/src/superqt/utils/__init__.py b/src/superqt/utils/__init__.py
index 3c9f41c..9b5594c 100644
--- a/src/superqt/utils/__init__.py
+++ b/src/superqt/utils/__init__.py
@@ -5,17 +5,20 @@ __all__ = (
     "FunctionWorker",
     "GeneratorWorker",
     "new_worker_qthread",
-    "QMessageHandler",
-    "thread_worker",
-    "WorkerBase",
-    "qthrottled",
     "qdebounced",
+    "QMessageHandler",
     "QSignalDebouncer",
     "QSignalThrottler",
+    "qthrottled",
+    "signals_blocked",
+    "thread_worker",
+    "WorkerBase",
 )
 
+
 from ._ensure_thread import ensure_main_thread, ensure_object_thread
 from ._message_handler import QMessageHandler
+from ._misc import signals_blocked
 from ._qthreading import (
     FunctionWorker,
     GeneratorWorker,
diff --git a/src/superqt/utils/_misc.py b/src/superqt/utils/_misc.py
new file mode 100644
index 0000000..085f191
--- /dev/null
+++ b/src/superqt/utils/_misc.py
@@ -0,0 +1,15 @@
+from contextlib import contextmanager
+from typing import TYPE_CHECKING, Iterator
+
+if TYPE_CHECKING:
+    from qtpy.QtCore import QObject
+
+
+@contextmanager
+def signals_blocked(obj: "QObject") -> Iterator[None]:
+    """Context manager to temporarily block signals emitted by QObject: `obj`."""
+    previous = obj.blockSignals(True)
+    try:
+        yield
+    finally:
+        obj.blockSignals(previous)
diff --git a/tests/test_utils.py b/tests/test_utils.py
new file mode 100644
index 0000000..f80c606
--- /dev/null
+++ b/tests/test_utils.py
@@ -0,0 +1,29 @@
+from unittest.mock import Mock
+
+from qtpy.QtCore import QObject, Signal
+
+from superqt.utils import signals_blocked
+
+
+def test_signal_blocker(qtbot):
+    """make sure context manager signal blocker works"""
+
+    class Emitter(QObject):
+        sig = Signal()
+
+    obj = Emitter()
+    receiver = Mock()
+    obj.sig.connect(receiver)
+
+    # make sure signal works
+    with qtbot.waitSignal(obj.sig):
+        obj.sig.emit()
+
+    receiver.assert_called_once()
+    receiver.reset_mock()
+
+    with signals_blocked(obj):
+        obj.sig.emit()
+        qtbot.wait(10)
+
+    receiver.assert_not_called()