add support for struct entities in MakeVariant

currently, structs are not parsed properly since `format()` has no handling for the reflect type
add a switch case to handle structs and encode some sane defaults if given an empty one

resolves #328

Signed-off-by: Charlie Doern <cdoern@redhat.com>

variant.go

@@ -73,7 +73,7 @@ func (v Variant) format() (string, bool) {
 	}
 	rv := reflect.ValueOf(v.value)
 	switch rv.Kind() {
-	case reflect.Slice:
+	case reflect.Slice, reflect.Array:
 		if rv.Len() == 0 {
 			return "[]", false
 		}
@@ -119,6 +119,23 @@ func (v Variant) format() (string, bool) {
 		}
 		buf.WriteByte('}')
 		return buf.String(), unamb
+	case reflect.Struct:
+		if rv.NumField() == 0 {
+			return "{}", false
+		}
+		unamb := true
+		var buf bytes.Buffer
+		buf.WriteString("{")
+		kvs := make([]string, rv.NumField())
+		for i := 0; i < rv.NumField(); i++ {
+			s, b := MakeVariant(rv.Field(i).Interface()).format()
+			unamb = unamb && b
+			buf.WriteString(s)
+			kvs[i] = buf.String()
+		}
+		buf.WriteString("}")
+		return buf.String(), unamb
+
 	}
 	return `"INVALID"`, true
 }

variant_test.go

@@ -5,10 +5,16 @@ import (
 	"testing"
 )
 
+type Testing struct {
+	First  string
+	Second uint64
+}
+
 var variantFormatTests = []struct {
 	v interface{}
 	s string
 }{
+	{[]Testing{{First: "testing", Second: 123}}, "@a(st) [{\"testing\"123}]"},
 	{int32(1), `1`},
 	{"foo", `"foo"`},
 	{ObjectPath("/org/foo"), `@o "/org/foo"`},