From 0c3d92310090ac82848c4a4607ca6f1f6815c6bd Mon Sep 17 00:00:00 2001
From: Brian Mego <brianmego@gmail.com>
Date: Mon, 3 Aug 2020 21:28:48 -0500
Subject: [PATCH] Adds walrus test and python 3.7/3.8 tox definitions

---
 tox.ini                             |  2 +-
 yapf/yapflib/py3compat.py           |  2 ++
 yapftests/reformatter_basic_test.py | 13 +++++++++++++
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/tox.ini b/tox.ini
index dca30d2b3..f42b884f0 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist=py27,py34,py35,py36
+envlist=py27,py34,py35,py36,py37,py38
 
 [testenv]
 commands=
diff --git a/yapf/yapflib/py3compat.py b/yapf/yapflib/py3compat.py
index 5373b013a..7c9052374 100644
--- a/yapf/yapflib/py3compat.py
+++ b/yapf/yapflib/py3compat.py
@@ -20,6 +20,8 @@
 
 PY3 = sys.version_info[0] >= 3
 PY36 = sys.version_info[0] >= 3 and sys.version_info[1] >= 6
+PY37 = sys.version_info[0] >= 3 and sys.version_info[1] >= 7
+PY38 = sys.version_info[0] >= 3 and sys.version_info[1] >= 8
 
 if PY3:
   StringIO = io.StringIO
diff --git a/yapftests/reformatter_basic_test.py b/yapftests/reformatter_basic_test.py
index 50cfdbc56..d6155adfe 100644
--- a/yapftests/reformatter_basic_test.py
+++ b/yapftests/reformatter_basic_test.py
@@ -3033,6 +3033,19 @@ def testForceMultilineDict_False(self):
     finally:
       style.SetGlobalStyle(style.CreateYapfStyle())
 
+  @unittest.skipUnless(py3compat.PY38, 'Requires Python 3.8')
+  def testWalrus(self):
+    unformatted_code = textwrap.dedent("""\
+      if (x  :=  len([1]*1000)>100):
+        print(f'{x} is pretty big' )
+    """)
+    expected = textwrap.dedent("""\
+      if (x := len([1] * 1000) > 100):
+        print(f'{x} is pretty big')
+    """)
+    uwlines = yapf_test_helper.ParseAndUnwrap(unformatted_code)
+    self.assertCodeEqual(expected, reformatter.Reformat(uwlines))
+
 
 if __name__ == '__main__':
   unittest.main()