ADD: config: test json unmarshal into prefilled struct

config/json_test.go

@@ -0,0 +1,114 @@
+package config_test
+
+import (
+	"encoding/json"
+	"reflect"
+	"testing"
+	"time"
+)
+
+type PrefilledSimple struct {
+	IntEmpty    int
+	IntKeep     int
+	IntOverride int
+
+	StringEmpty    string
+	StringKeep     string
+	StringOverride string
+
+	DurationEmpty    time.Duration
+	DurationKeep     time.Duration
+	DurationOverride time.Duration
+
+	BytesEmpty    []byte
+	BytesKeep     []byte
+	BytesOverride []byte
+}
+
+func TestPrefilled_Simple(t *testing.T) {
+	input := PrefilledSimple{
+		IntKeep:          10,
+		IntOverride:      10,
+		StringKeep:       "hello",
+		StringOverride:   "hello",
+		DurationKeep:     time.Second,
+		DurationOverride: time.Second,
+		BytesKeep:        []byte("_nian_"),
+		BytesOverride:    []byte("_nian_"),
+	}
+	data := []byte(`{"IntOverride":20,"StringOverride":"world","DurationOverride":60000000000,"BytesOverride":"X3h4eHhf"}`)
+	want := PrefilledSimple{
+		IntKeep:          10,
+		IntOverride:      20,
+		StringKeep:       "hello",
+		StringOverride:   "world",
+		DurationKeep:     time.Second,
+		DurationOverride: time.Minute,
+		BytesKeep:        []byte("_nian_"),
+		BytesOverride:    []byte("_xxxx_"),
+	}
+
+	if err := json.Unmarshal(data, &input); err != nil {
+		t.Fatalf("json.Unmarshal() error: %v", err)
+	}
+	if !reflect.DeepEqual(input, want) {
+		t.Fatalf("json.Unmarshal() result:\n  get  %+v\n  want %+v", input, want)
+	}
+}
+
+type IntBox struct {
+	IntEmpty    int
+	IntKeep     int
+	IntOverride int
+}
+
+type IntBox2 struct {
+	BoxEmpty    IntBox
+	BoxKeep     IntBox
+	BoxOverride IntBox
+}
+
+type PrefilledNested struct {
+	BoxEmpty    IntBox
+	BoxKeep     IntBox
+	BoxOverride IntBox
+
+	Box2Empty    IntBox2
+	Box2Keep     IntBox2
+	Box2Override IntBox2
+}
+
+func TestPrefilled_Nested(t *testing.T) {
+	input := PrefilledNested{
+		BoxKeep:     IntBox{IntKeep: 10, IntOverride: 10},
+		BoxOverride: IntBox{IntKeep: 10, IntOverride: 10},
+		Box2Keep: IntBox2{
+			BoxKeep:     IntBox{IntKeep: 10, IntOverride: 10},
+			BoxOverride: IntBox{IntKeep: 10, IntOverride: 10},
+		},
+		Box2Override: IntBox2{
+			BoxKeep:     IntBox{IntKeep: 10, IntOverride: 10},
+			BoxOverride: IntBox{IntKeep: 10, IntOverride: 10},
+		},
+	}
+	data := []byte(`{"BoxOverride":{"IntOverride":20},"Box2Override":{"BoxOverride":{"IntOverride":20}}}`)
+	want := PrefilledNested{
+		BoxKeep:     IntBox{IntKeep: 10, IntOverride: 10},
+		BoxOverride: IntBox{IntKeep: 10, IntOverride: 20},
+		Box2Keep: IntBox2{
+			BoxKeep:     IntBox{IntKeep: 10, IntOverride: 10},
+			BoxOverride: IntBox{IntKeep: 10, IntOverride: 10},
+		},
+		Box2Override: IntBox2{
+			BoxKeep:     IntBox{IntKeep: 10, IntOverride: 10},
+			BoxOverride: IntBox{IntKeep: 10, IntOverride: 20},
+		},
+	}
+
+	if err := json.Unmarshal(data, &input); err != nil {
+		t.Fatalf("json.Unmarshal() error: %v", err)
+	}
+	if !reflect.DeepEqual(input, want) {
+		t.Fatalf("json.Unmarshal() result:\n  get  %+v\n  want %+v", input, want)
+	}
+}