strconv: add test that trips up other implementations

R=r, gri1
CC=golang-dev
https://golang.org/cl/4092045

src/pkg/strconv/atof_test.go

@@ -103,6 +103,11 @@ var atoftests = []atofTest{
 	{"1e", "0", os.EINVAL},
 	{"1e-", "0", os.EINVAL},
 	{".e-1", "0", os.EINVAL},
+
+	// http://www.exploringbinary.com/java-hangs-when-converting-2-2250738585072012e-308/
+	{"2.2250738585072012e-308", "2.2250738585072014e-308", nil},
+	// http://www.exploringbinary.com/php-hangs-on-numeric-value-2-2250738585072011e-308/
+	{"2.2250738585072011e-308", "2.225073858507201e-308", nil},
 }
 
 func init() {

src/pkg/strconv/ftoa_test.go

@@ -118,6 +118,12 @@ var ftoatests = []ftoaTest{
 	{0.5, 'f', 1, "0.5"},
 	{0.5, 'f', 0, "0"},
 	{1.5, 'f', 0, "2"},
+
+	// http://www.exploringbinary.com/java-hangs-when-converting-2-2250738585072012e-308/
+	{2.2250738585072012e-308, 'g', -1, "2.2250738585072014e-308"},
+	// TODO: uncomment after fixing issue 1463.
+	// http://www.exploringbinary.com/php-hangs-on-numeric-value-2-2250738585072011e-308/
+	// {2.2250738585072011e-308, 'g', -1, "2.225073858507201e-308"},
 }
 
 func TestFtoa(t *testing.T) {