From 948747a9397fb06825d8257788b7941c541cb819 Mon Sep 17 00:00:00 2001
From: Serhiy Storchaka <storchaka@gmail.com>
Date: Mon, 18 Sep 2023 19:00:11 +0300
Subject: [PATCH 1/2] gh-109546: Add more tests for formatting floats and
 fractions

---
 Lib/test/test_float.py     |  8 ++++++--
 Lib/test/test_fractions.py | 24 ++++++++++++++++++++++++
 2 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/Lib/test/test_float.py b/Lib/test/test_float.py
index c4ee1e08251d63..749b6d2c6adb48 100644
--- a/Lib/test/test_float.py
+++ b/Lib/test/test_float.py
@@ -733,8 +733,12 @@ def test_format_testfile(self):
 
                 lhs, rhs = map(str.strip, line.split('->'))
                 fmt, arg = lhs.split()
-                self.assertEqual(fmt % float(arg), rhs)
-                self.assertEqual(fmt % -float(arg), '-' + rhs)
+                f = float(arg)
+                self.assertEqual(fmt % f, rhs)
+                self.assertEqual(fmt % -f, '-' + rhs)
+                if fmt != '%r':
+                    self.assertEqual(format(f, fmt[1:]), rhs)
+                    self.assertEqual(format(-f, fmt[1:]), '-' + rhs)
 
     def test_issue5864(self):
         self.assertEqual(format(123.456, '.4'), '123.5')
diff --git a/Lib/test/test_fractions.py b/Lib/test/test_fractions.py
index e112f49d2e7944..ccda2dad8359a1 100644
--- a/Lib/test/test_fractions.py
+++ b/Lib/test/test_fractions.py
@@ -1220,6 +1220,30 @@ def test_invalid_formats(self):
                 with self.assertRaises(ValueError):
                     format(fraction, spec)
 
+    @requires_IEEE_754
+    def test_float_format_testfile(self):
+        from test.test_float import format_testfile
+        with open(format_testfile, encoding="utf-8") as testfile:
+            for line in testfile:
+                if line.startswith('--'):
+                    continue
+                line = line.strip()
+                if not line:
+                    continue
+
+                lhs, rhs = map(str.strip, line.split('->'))
+                fmt, arg = lhs.split()
+                if fmt == '%r':
+                    continue
+                with self.subTest(fmt=fmt, arg=arg):
+                    f = F(float(arg))
+                    self.assertEqual(format(f, fmt[1:]), rhs)
+                    if f:  # skip negative zero
+                        self.assertEqual(format(-f, fmt[1:]), '-' + rhs)
+                    f = F(arg)
+                    self.assertEqual(float(format(f, fmt[1:])), float(rhs))
+                    self.assertEqual(float(format(-f, fmt[1:])), float('-' + rhs))
+
 
 if __name__ == '__main__':
     unittest.main()

From 22245e4dd490c79ecc38aea7a30d8990169234d8 Mon Sep 17 00:00:00 2001
From: Serhiy Storchaka <storchaka@gmail.com>
Date: Mon, 18 Sep 2023 20:42:22 +0300
Subject: [PATCH 2/2] Address review comments.

---
 Lib/test/test_float.py     |  5 +++--
 Lib/test/test_fractions.py | 14 +++++++++-----
 2 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/Lib/test/test_float.py b/Lib/test/test_float.py
index 749b6d2c6adb48..84270ce7dd4780 100644
--- a/Lib/test/test_float.py
+++ b/Lib/test/test_float.py
@@ -737,8 +737,9 @@ def test_format_testfile(self):
                 self.assertEqual(fmt % f, rhs)
                 self.assertEqual(fmt % -f, '-' + rhs)
                 if fmt != '%r':
-                    self.assertEqual(format(f, fmt[1:]), rhs)
-                    self.assertEqual(format(-f, fmt[1:]), '-' + rhs)
+                    fmt2 = fmt[1:]
+                    self.assertEqual(format(f, fmt2), rhs)
+                    self.assertEqual(format(-f, fmt2), '-' + rhs)
 
     def test_issue5864(self):
         self.assertEqual(format(123.456, '.4'), '123.5')
diff --git a/Lib/test/test_fractions.py b/Lib/test/test_fractions.py
index ccda2dad8359a1..4f4ea7c03f9a4c 100644
--- a/Lib/test/test_fractions.py
+++ b/Lib/test/test_fractions.py
@@ -7,6 +7,7 @@
 import operator
 import fractions
 import functools
+import os
 import sys
 import typing
 import unittest
@@ -15,6 +16,9 @@
 from pickle import dumps, loads
 F = fractions.Fraction
 
+#locate file with float format test values
+test_dir = os.path.dirname(__file__) or os.curdir
+format_testfile = os.path.join(test_dir, 'formatfloat_testcases.txt')
 
 class DummyFloat(object):
     """Dummy float class for testing comparisons with Fractions"""
@@ -1222,7 +1226,6 @@ def test_invalid_formats(self):
 
     @requires_IEEE_754
     def test_float_format_testfile(self):
-        from test.test_float import format_testfile
         with open(format_testfile, encoding="utf-8") as testfile:
             for line in testfile:
                 if line.startswith('--'):
@@ -1235,14 +1238,15 @@ def test_float_format_testfile(self):
                 fmt, arg = lhs.split()
                 if fmt == '%r':
                     continue
+                fmt2 = fmt[1:]
                 with self.subTest(fmt=fmt, arg=arg):
                     f = F(float(arg))
-                    self.assertEqual(format(f, fmt[1:]), rhs)
+                    self.assertEqual(format(f, fmt2), rhs)
                     if f:  # skip negative zero
-                        self.assertEqual(format(-f, fmt[1:]), '-' + rhs)
+                        self.assertEqual(format(-f, fmt2), '-' + rhs)
                     f = F(arg)
-                    self.assertEqual(float(format(f, fmt[1:])), float(rhs))
-                    self.assertEqual(float(format(-f, fmt[1:])), float('-' + rhs))
+                    self.assertEqual(float(format(f, fmt2)), float(rhs))
+                    self.assertEqual(float(format(-f, fmt2)), float('-' + rhs))
 
 
 if __name__ == '__main__':