From: Raymond Hettinger <rhettinger@users.noreply.github.com>
Date: Sun, 24 Feb 2019 06:19:01 +0000 (-0800)
Subject: bpo-36018: Make __pos__ return a distinct instance of NormDist (GH-12009)
X-Git-Tag: v3.8.0a2~8
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=79fbcc597dfd039d3261fffcb519b5ec5a18df9d;p=thirdparty%2FPython%2Fcpython.git

bpo-36018: Make __pos__ return a distinct instance of NormDist (GH-12009)



https://bugs.python.org/issue36018
---

diff --git a/Lib/statistics.py b/Lib/statistics.py
index a73001ac554c..bf10e19c0d41 100644
--- a/Lib/statistics.py
+++ b/Lib/statistics.py
@@ -762,7 +762,7 @@ class NormalDist:
         return NormalDist(x1.mu / x2, x1.sigma / fabs(x2))
 
     def __pos__(x1):
-        return x1
+        return NormalDist(x1.mu, x1.sigma)
 
     def __neg__(x1):
         return NormalDist(-x1.mu, x1.sigma)
diff --git a/Lib/test/test_statistics.py b/Lib/test/test_statistics.py
index a65fbe8dd259..9549240f9092 100644
--- a/Lib/test/test_statistics.py
+++ b/Lib/test/test_statistics.py
@@ -2128,6 +2128,18 @@ class TestNormalDist(unittest.TestCase):
         with self.assertRaises(statistics.StatisticsError):
             Y.cdf(90)
 
+    def test_unary_operations(self):
+        NormalDist = statistics.NormalDist
+        X = NormalDist(100, 12)
+        Y = +X
+        self.assertIsNot(X, Y)
+        self.assertEqual(X.mu, Y.mu)
+        self.assertEqual(X.sigma, Y.sigma)
+        Y = -X
+        self.assertIsNot(X, Y)
+        self.assertEqual(X.mu, -Y.mu)
+        self.assertEqual(X.sigma, Y.sigma)
+
     def test_same_type_addition_and_subtraction(self):
         NormalDist = statistics.NormalDist
         X = NormalDist(100, 12)