math/big: fix Int.Exp
Fixes #7814.
LGTM=agl, adonovan
R=agl, adonovan
CC=golang-codereviews
https://golang.org/cl/90080043
diff --git a/src/pkg/math/big/int_test.go b/src/pkg/math/big/int_test.go
index 3dd9c5b..299dc72 100644
--- a/src/pkg/math/big/int_test.go
+++ b/src/pkg/math/big/int_test.go
@@ -768,6 +768,19 @@
x, y, m string
out string
}{
+ // y <= 0
+ {"0", "0", "", "1"},
+ {"1", "0", "", "1"},
+ {"-10", "0", "", "1"},
+ {"1234", "-1", "", "1"},
+
+ // m == 1
+ {"0", "0", "1", "0"},
+ {"1", "0", "1", "0"},
+ {"-10", "0", "1", "0"},
+ {"1234", "-1", "1", "0"},
+
+ // misc
{"5", "-7", "", "1"},
{"-5", "-7", "", "1"},
{"5", "0", "", "1"},
