Discord: add Enum type

utils/json/option/enum.go

@@ -0,0 +1,34 @@
+package option
+
+import "strconv"
+
+// EnumNull is the value used to represent JSON null.
+// It should never be used as a value, as it won't get serialized as such.
+const EnumNull = -1
+
+// Enum is a nullable version of a uint8.
+// Enum values should only consist of positive values, as negative values are reserved for internal constants, such as
+// EnumNull.
+// This also mean that only 7 of the 8 Bit will be available for storage.
+type Enum int8
+
+// Int8ToJSON converts the passed Enum to a byte slice with it's JSON representation.
+func EnumToJSON(i Enum) []byte {
+	if i == EnumNull {
+		return []byte("null")
+	} else {
+		return []byte(strconv.Itoa(int(i)))
+	}
+}
+
+// Int8FromJSON decodes the Enum stored as JSON src the passed byte slice.
+func EnumFromJSON(b []byte) (Enum, error) {
+	s := string(b)
+
+	if s == "null" {
+		return EnumNull, nil
+	} else {
+		i, err := strconv.ParseUint(s, 10, 7)
+		return Enum(i), err
+	}
+}

utils/json/option/enum_test.go

@@ -0,0 +1,83 @@
+package option
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestInt8ToJSON(t *testing.T) {
+	testCases := []struct {
+		name   string
+		src    Enum
+		expect []byte
+	}{
+		{
+			name:   "null",
+			src:    EnumNull,
+			expect: []byte("null"),
+		},
+		{
+			name:   "value",
+			src:    12,
+			expect: []byte("12"),
+		},
+	}
+
+	for _, c := range testCases {
+		t.Run(c.name, func(t *testing.T) {
+			actual := EnumToJSON(c.src)
+
+			if !reflect.DeepEqual(actual, c.expect) {
+				t.Errorf("expected nullable.Int8ToJSON to return: %+v, but got: %+v", c.expect, actual)
+			}
+		})
+	}
+}
+
+func TestInt8FromJSON(t *testing.T) {
+	testCases := []struct {
+		name   string
+		src    []byte
+		expect Enum
+		err    bool
+	}{
+		{
+			name:   "null",
+			src:    []byte("null"),
+			expect: EnumNull,
+			err:    false,
+		},
+		{
+			name:   "value",
+			src:    []byte("12"),
+			expect: 12,
+			err:    false,
+		},
+		{
+			name:   "invalid input",
+			src:    []byte("NaN"),
+			expect: 0,
+			err:    true,
+		},
+	}
+
+	for _, c := range testCases {
+		t.Run(c.name, func(t *testing.T) {
+			actual, err := EnumFromJSON(c.src)
+
+			if c.err {
+				if err == nil {
+					t.Error("expected nullable.Int8FromJSON to return an error, but it did not")
+				}
+			} else {
+				if !reflect.DeepEqual(actual, c.expect) {
+					t.Errorf("expected nullable.Int8FromJSON to return: %+v, but got: %+v", c.expect, actual)
+				}
+
+				if err != nil {
+					t.Errorf("nullable.Int8FromJSON returned an error: %s", err.Error())
+				}
+			}
+		})
+	}
+}