From a604900d4311adb9824da78378c60bf8bdf5b2d5 Mon Sep 17 00:00:00 2001
From: Philipp Rudiger <prudiger@anaconda.com>
Date: Tue, 12 May 2020 22:33:49 +0200
Subject: [PATCH] Add tests for deep copying watchers

---
 tests/API1/testwatch.py | 31 ++++++++++++++++++++++++++++---
 1 file changed, 28 insertions(+), 3 deletions(-)

diff --git a/tests/API1/testwatch.py b/tests/API1/testwatch.py
index 34cb8fb59..6b0111729 100644
--- a/tests/API1/testwatch.py
+++ b/tests/API1/testwatch.py
@@ -1,14 +1,15 @@
 """
 Unit test for watch mechanism
 """
-from . import API1TestCase
-
-from .utils import MockLoggingHandler
+import copy
 
 import param
 
 from param.parameterized import discard_events
 
+from . import API1TestCase
+from .utils import MockLoggingHandler
+
 
 class Accumulator(object):
 
@@ -37,6 +38,9 @@ class SimpleWatchExample(param.Parameterized):
     c = param.Parameter(default=0)
     d = param.Integer(default=0)
 
+    def method(self, event):
+        self.b = self.a * 2
+
 
 class SimpleWatchSubclass(SimpleWatchExample):
     pass
@@ -466,6 +470,18 @@ def test_nested_batched_watch_not_onlychanged(self):
         self.assertEqual(args[1].new, 0)
         self.assertEqual(args[1].type, 'set')
 
+    def test_watch_deepcopy(self):
+        obj = SimpleWatchExample()
+
+        obj.param.watch(obj.method, ['a'])
+
+        copied = copy.deepcopy(obj)
+
+        copied.a = 2
+
+        self.assertEqual(copied.b, 4)
+        self.assertEqual(obj.b, 0)
+
 
 class TestWatchMethod(API1TestCase):
 
@@ -523,6 +539,15 @@ def test_depends_with_watch_on_subclass(self):
         obj.b = 3
         self.assertEqual(obj.c, 6)
 
+    def test_watcher_method_deepcopy(self):
+        obj = WatchMethodExample(b=5)
+
+        copied = copy.deepcopy(obj)
+
+        copied.b = 11
+        self.assertEqual(copied.b, 10)
+        self.assertEqual(obj.b, 5)
+
 
 class TestWatchValues(API1TestCase):