strconv: add atoi tests for uncommon bases and syntax errors

Edge cases like base 2 and 36 conversions are now covered.
Many tests are mirrored from the itoa tests.

Added more test cases for syntax errors.

Change-Id: Iad8b2fb4854f898c2bfa18cdeb0cb4a758fcfc2e
Reviewed-on: https://go-review.googlesource.com/2463Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

src/strconv/atoi_test.go

@@ -33,12 +33,16 @@ var atoui64tests = []atoui64Test{
 var btoui64tests = []atoui64Test{
 	{"", 0, ErrSyntax},
 	{"0", 0, nil},
+	{"0x", 0, ErrSyntax},
+	{"0X", 0, ErrSyntax},
 	{"1", 1, nil},
 	{"12345", 12345, nil},
 	{"012345", 012345, nil},
 	{"0x12345", 0x12345, nil},
 	{"0X12345", 0x12345, nil},
 	{"12345x", 0, ErrSyntax},
+	{"0xabcdefg123", 0, ErrSyntax},
+	{"123456789abc", 0, ErrSyntax},
 	{"98765432100", 98765432100, nil},
 	{"18446744073709551615", 1<<64 - 1, nil},
 	{"18446744073709551616", 1<<64 - 1, ErrRange},
@@ -77,28 +81,61 @@ var atoi64tests = []atoi64Test{
 	{"-9223372036854775809", -1 << 63, ErrRange},
 }
 
-var btoi64tests = []atoi64Test{
-	{"", 0, ErrSyntax},
-	{"0", 0, nil},
-	{"-0", 0, nil},
-	{"1", 1, nil},
-	{"-1", -1, nil},
-	{"12345", 12345, nil},
-	{"-12345", -12345, nil},
-	{"012345", 012345, nil},
-	{"-012345", -012345, nil},
-	{"0x12345", 0x12345, nil},
-	{"-0X12345", -0x12345, nil},
-	{"12345x", 0, ErrSyntax},
-	{"-12345x", 0, ErrSyntax},
-	{"98765432100", 98765432100, nil},
-	{"-98765432100", -98765432100, nil},
-	{"9223372036854775807", 1<<63 - 1, nil},
-	{"-9223372036854775807", -(1<<63 - 1), nil},
-	{"9223372036854775808", 1<<63 - 1, ErrRange},
-	{"-9223372036854775808", -1 << 63, nil},
-	{"9223372036854775809", 1<<63 - 1, ErrRange},
-	{"-9223372036854775809", -1 << 63, ErrRange},
+type btoi64Test struct {
+	in   string
+	base int
+	out  int64
+	err  error
+}
+
+var btoi64tests = []btoi64Test{
+	{"", 0, 0, ErrSyntax},
+	{"0", 0, 0, nil},
+	{"-0", 0, 0, nil},
+	{"1", 0, 1, nil},
+	{"-1", 0, -1, nil},
+	{"12345", 0, 12345, nil},
+	{"-12345", 0, -12345, nil},
+	{"012345", 0, 012345, nil},
+	{"-012345", 0, -012345, nil},
+	{"0x12345", 0, 0x12345, nil},
+	{"-0X12345", 0, -0x12345, nil},
+	{"12345x", 0, 0, ErrSyntax},
+	{"-12345x", 0, 0, ErrSyntax},
+	{"98765432100", 0, 98765432100, nil},
+	{"-98765432100", 0, -98765432100, nil},
+	{"9223372036854775807", 0, 1<<63 - 1, nil},
+	{"-9223372036854775807", 0, -(1<<63 - 1), nil},
+	{"9223372036854775808", 0, 1<<63 - 1, ErrRange},
+	{"-9223372036854775808", 0, -1 << 63, nil},
+	{"9223372036854775809", 0, 1<<63 - 1, ErrRange},
+	{"-9223372036854775809", 0, -1 << 63, ErrRange},
+
+	// other bases
+	{"g", 17, 16, nil},
+	{"10", 25, 25, nil},
+	{"holycow", 35, (((((17*35+24)*35+21)*35+34)*35+12)*35+24)*35 + 32, nil},
+	{"holycow", 36, (((((17*36+24)*36+21)*36+34)*36+12)*36+24)*36 + 32, nil},
+
+	// base 2
+	{"0", 2, 0, nil},
+	{"-1", 2, -1, nil},
+	{"1010", 2, 10, nil},
+	{"1000000000000000", 2, 1 << 15, nil},
+	{"111111111111111111111111111111111111111111111111111111111111111", 2, 1<<63 - 1, nil},
+	{"1000000000000000000000000000000000000000000000000000000000000000", 2, 1<<63 - 1, ErrRange},
+	{"-1000000000000000000000000000000000000000000000000000000000000000", 2, -1 << 63, nil},
+	{"-1000000000000000000000000000000000000000000000000000000000000001", 2, -1 << 63, ErrRange},
+
+	// base 8
+	{"-10", 8, -8, nil},
+	{"57635436545", 8, 057635436545, nil},
+	{"100000000", 8, 1 << 24, nil},
+
+	// base 16
+	{"10", 16, 16, nil},
+	{"-123456789abcdef", 16, -0x123456789abcdef, nil},
+	{"7fffffffffffffff", 16, 1<<63 - 1, nil},
 }
 
 type atoui32Test struct {
@@ -234,7 +271,7 @@ func TestParseInt64(t *testing.T) {
 func TestParseInt64Base(t *testing.T) {
 	for i := range btoi64tests {
 		test := &btoi64tests[i]
-		out, err := ParseInt(test.in, 0, 64)
+		out, err := ParseInt(test.in, test.base, 64)
 		if test.out != out || !reflect.DeepEqual(test.err, err) {
 			t.Errorf("ParseInt(%q) = %v, %v want %v, %v",
 				test.in, out, err, test.out, test.err)