feat: extend validation for default enum value (#245)

schema.go

@@ -1270,7 +1270,24 @@ func isValidDefault(schema Schema, def any) (any, bool) {
 	case Null:
 		return nullDefault, def == nil
 
-	case String, Bytes, Enum, Fixed:
+	case Enum:
+		v, ok := def.(string)
+		if !ok || len(v) == 0 {
+			return def, false
+		}
+
+		enumSchema := schema.(*EnumSchema)
+		found := false
+		for i := range enumSchema.symbols {
+			if def == enumSchema.symbols[i] {
+				found = true
+				break
+			}
+		}
+
+		return def, found
+
+	case String, Bytes, Fixed:
 		if _, ok := def.(string); ok {
 			return def, true
 		}

schema_internal_test.go

@@ -161,10 +161,28 @@ func TestIsValidDefault(t *testing.T) {
 				s, _ := NewEnumSchema("foo", "", []string{"BAR"})
 				return s
 			},
-			def:    "test",
-			want:   "test",
+			def:    "BAR",
+			want:   "BAR",
 			wantOk: true,
 		},
+		{
+			name: "Enum Invalid Default",
+			schemaFn: func() Schema {
+				s, _ := NewEnumSchema("foo", "", []string{"BAR"})
+				return s
+			},
+			def:    "BUP",
+			wantOk: false,
+		},
+		{
+			name: "Enum Empty string",
+			schemaFn: func() Schema {
+				s, _ := NewEnumSchema("foo", "", []string{"BAR"})
+				return s
+			},
+			def:    "",
+			wantOk: false,
+		},
 		{
 			name: "Enum Invalid Type",
 			schemaFn: func() Schema {