Add testcases from bug report #9980.
diff --git a/Lib/test/formatfloat_testcases.txt b/Lib/test/formatfloat_testcases.txt
index 9f045b7..25c07ba 100644
--- a/Lib/test/formatfloat_testcases.txt
+++ b/Lib/test/formatfloat_testcases.txt
@@ -279,6 +279,11 @@
%.2g 0.000123 -> 0.00012
%.2g 0.0000123 -> 1.2e-05
+-- bad cases from http://bugs.python.org/issue9980
+%.12g 38210.0 -> 38210
+%.12g 37210.0 -> 37210
+%.12g 36210.0 -> 36210
+
-- alternate g formatting: always include decimal point and
-- exactly <precision> significant digits.
%#.0g 0 -> 0.