is device token valid

#13

push/device_token.go

@@ -0,0 +1,13 @@
+package push
+
+import "encoding/hex"
+
+// IsDeviceTokenValid checks if s is a hexadecimal token of the correct length.
+func IsDeviceTokenValid(s string) bool {
+	// TODO: In 2016, they may be growing up to 100 bytes (200 hexadecimal digits).
+	if len(s) != 64 {
+		return false
+	}
+	_, err := hex.DecodeString(s)
+	return err == nil
+}

push/device_token_test.go

@@ -0,0 +1,35 @@
+package push_test
+
+import (
+	"testing"
+
+	"github.com/RobotsAndPencils/buford/push"
+)
+
+func TestInvalidDeviceTokens(t *testing.T) {
+	tokens := []string{
+		"invalid-token",
+		"f00f",
+		"abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijkl",
+		"50c4afb5 9197d2ba d1794be4 e63f2532 ee18c660 0ee655fa 38b0b380 94fd8847",
+		"<50c4afb5 9197d2ba d1794be4 e63f2532 ee18c660 0ee655fa 38b0b380 94fd8847>",
+	}
+
+	for _, token := range tokens {
+		if push.IsDeviceTokenValid(token) {
+			t.Errorf("Expected device token %q to be invalid.", token)
+		}
+	}
+}
+
+func TestValidDeviceToken(t *testing.T) {
+	tokens := []string{
+		"c2732227a1d8021cfaf781d71fb2f908c61f5861079a00954a5453f1d0281433",
+	}
+
+	for _, token := range tokens {
+		if !push.IsDeviceTokenValid(token) {
+			t.Errorf("Expected device token %q to be valid.", token)
+		}
+	}
+}