Issue #5920: Changed format.__float__ and complex.__float__ to use a precision of 12 when using the empty presentation type. This more closely matches str()'s behavior and reduces surprises when adding alignment flags to an empty format string. Patch by Mark Dickinson.
diff --git a/Lib/test/test_complex.py b/Lib/test/test_complex.py
index 557e952..56e9083 100644
--- a/Lib/test/test_complex.py
+++ b/Lib/test/test_complex.py
@@ -467,6 +467,16 @@
self.assertEqual(format(3+0j, ''), str(3+0j))
self.assertEqual(format(3.2+0j, ''), str(3.2+0j))
+ # empty presentation type should still be analogous to str,
+ # even when format string is nonempty (issue #5920).
+ self.assertEqual(format(3.2+0j, '-'), str(3.2+0j))
+ self.assertEqual(format(3.2+0j, '<'), str(3.2+0j))
+ z = 4/7. - 100j/7.
+ self.assertEqual(format(z, ''), str(z))
+ self.assertEqual(format(z, '-'), str(z))
+ self.assertEqual(format(z, '<'), str(z))
+ self.assertEqual(format(z, '10'), str(z))
+
self.assertEqual(format(1+3j, 'g'), '1+3j')
self.assertEqual(format(3j, 'g'), '0+3j')
self.assertEqual(format(1.5+3.5j, 'g'), '1.5+3.5j')