add tests

core.go

@@ -164,32 +164,43 @@ func TimeFromString(t *testing.T, format, datetime string) time.Time {
 	return dt
 }
 
-const LayoutRequestDateDefault = "2006-01-02"
+const ShortDateLayout = "2006-01-02"
 
-type RequestDate struct {
+// Do not use this structure for responses
+// as there are no ways to unmarshal to any layout
+// and leave nil if json field is null
+type TimeFormat struct {
 	time.Time
 	layout string
 }
 
-func NewRequestDate(t time.Time, layout string) *RequestDate {
-	return &RequestDate{
+func NewTimeFormat(t time.Time, layout string) *TimeFormat {
+	return &TimeFormat{
 		Time:   t,
 		layout: layout,
 	}
 }
 
-func (rd *RequestDate) UnmarshalJSON(b []byte) (err error) {
+func newTimeLayout(layout string) *TimeFormat {
+	return &TimeFormat{
+		layout: layout,
+	}
+}
+
+func (rd *TimeFormat) UnmarshalJSON(b []byte) error {
+	var err error
+
 	s := strings.Trim(string(b), `"`) // remove quotes
+
+	// Added for extra accuracy
+	// encoding/json won't invoke this method if field is null
 	if s == "null" {
-		return
+		return nil
 	}
 	rd.Time, err = time.Parse(rd.layout, s)
-	return
+	return err
 }
 
-func (rd *RequestDate) MarshalJSON() ([]byte, error) {
-	if rd.Time.IsZero() {
-		return nil, nil
-	}
-	return []byte(fmt.Sprintf(`"%s"`, rd.Time.Format(rd.layout))), nil
+func (rd *TimeFormat) MarshalJSON() ([]byte, error) {
+	return []byte(fmt.Sprintf(`%q`, rd.Time.Format(rd.layout))), nil
 }

core_test.go

@@ -1,8 +1,10 @@
 package core
 
 import (
+	"encoding/json"
 	"reflect"
 	"testing"
+	"time"
 
 	"github.com/stretchr/testify/assert"
 )
@@ -54,3 +56,97 @@ func TestDefaultValues(t *testing.T) {
 	assert.Equal(t, "empty_string", req.OptionalStructure.EmptyField)
 	assert.Equal(t, (*DefaultStructure)(nil), req.EmptyOptionalStructure)
 }
+
+func TestTimeFormat(t *testing.T) {
+	t.Run("Time Format Marshalling", func(t *testing.T) {
+		tests := []struct {
+			ft           *TimeFormat
+			layout       string
+			expectedJSON string
+			diff         time.Duration
+		}{
+			{
+				ft:           NewTimeFormat(time.Date(2024, 4, 30, 15, 42, 12, 55, time.FixedZone("Test Zone", 0)), ShortDateLayout),
+				layout:       ShortDateLayout,
+				expectedJSON: `"2024-04-30"`,
+				diff:         time.Hour * 24,
+			},
+			{
+				ft:           NewTimeFormat(time.Date(2024, 4, 30, 0, 0, 0, 0, time.FixedZone("Test Zone", 0)), ShortDateLayout),
+				layout:       ShortDateLayout,
+				expectedJSON: `"2024-04-30"`,
+				diff:         time.Hour * 24,
+			},
+			{
+				ft:           NewTimeFormat(time.Time{}, ShortDateLayout),
+				layout:       ShortDateLayout,
+				expectedJSON: `"0001-01-01"`,
+				diff:         time.Hour * 24,
+			},
+			{
+				ft:           nil,
+				layout:       ShortDateLayout,
+				expectedJSON: `null`,
+				diff:         time.Hour * 24,
+			},
+		}
+
+		for _, tc := range tests {
+			marshaled, err := json.Marshal(tc.ft)
+			assert.Equal(t, nil, err)
+			assert.Equal(t, tc.expectedJSON, string(marshaled))
+
+			unmarshaled := newTimeLayout(tc.layout)
+			err = json.Unmarshal(marshaled, unmarshaled)
+			assert.Equal(t, nil, err)
+
+			if tc.ft != nil {
+				diffedTime := tc.ft.Add(-tc.diff)
+				assert.Equal(t, true, diffedTime.Before(unmarshaled.Time) || diffedTime.Equal(unmarshaled.Time))
+				assert.Equal(t, true, tc.ft.After(unmarshaled.Time) || tc.ft.Equal(unmarshaled.Time))
+			}
+		}
+	})
+
+	t.Run("Time Format in structure Marshalling", func(t *testing.T) {
+		type test struct {
+			Date *TimeFormat `json:"date"`
+		}
+
+		tests := []struct {
+			structure    *test
+			layout       string
+			expectedJSON string
+			diff         time.Duration
+		}{
+			{
+				structure:    &test{Date: NewTimeFormat(time.Date(2024, 4, 30, 5, 4, 7, 20, time.FixedZone("Test Zone", 0)), ShortDateLayout)},
+				layout:       ShortDateLayout,
+				expectedJSON: `{"date":"2024-04-30"}`,
+				diff:         time.Hour * 24,
+			},
+			{
+				structure:    &test{Date: nil},
+				layout:       ShortDateLayout,
+				expectedJSON: `{"date":null}`,
+				diff:         time.Hour * 24,
+			},
+		}
+
+		for _, tc := range tests {
+			marshaled, err := json.Marshal(tc.structure)
+			assert.Equal(t, nil, err)
+			assert.Equal(t, tc.expectedJSON, string(marshaled))
+
+			unmarshaled := &test{Date: newTimeLayout(tc.layout)}
+			err = json.Unmarshal(marshaled, unmarshaled)
+			assert.Equal(t, nil, err)
+
+			if tc.structure != nil && tc.structure.Date != nil {
+				diffedTime := tc.structure.Date.Add(-tc.diff)
+				assert.Equal(t, true, diffedTime.Before(unmarshaled.Date.Time) || diffedTime.Equal(unmarshaled.Date.Time))
+				assert.Equal(t, true, tc.structure.Date.After(unmarshaled.Date.Time) || tc.structure.Date.Equal(unmarshaled.Date.Time))
+			}
+		}
+	})
+}

ozon/analytics.go

@@ -13,10 +13,10 @@ type Analytics struct {
 
 type GetAnalyticsDataParams struct {
 	// Date from which the data will be in the report
-	DateFrom *core.RequestDate `json:"date_from"`
+	DateFrom *core.TimeFormat `json:"date_from"`
 
 	// Date up to which the data will be in the report
-	DateTo *core.RequestDate `json:"date_to"`
+	DateTo *core.TimeFormat `json:"date_to"`
 
 	// Items Enum: "unknownDimension" "sku" "spu" "day" "week" "month" "year" "category1" "category2" "category3" "category4" "brand" "modelID"
 	// Data grouping available to all sellers:

ozon/analytics_test.go

@@ -23,8 +23,8 @@ func TestGetAnalyticsData(t *testing.T) {
 			http.StatusOK,
 			map[string]string{"Client-Id": "my-client-id", "Api-Key": "my-api-key"},
 			&GetAnalyticsDataParams{
-				DateFrom:  core.NewRequestDate(time.Now().Add(time.Duration(30)*24*time.Hour), core.LayoutRequestDateDefault),
-				DateTo:    core.NewRequestDate(time.Now(), core.LayoutRequestDateDefault),
+				DateFrom:  core.NewTimeFormat(time.Now().Add(time.Duration(30)*24*time.Hour), core.ShortDateLayout),
+				DateTo:    core.NewTimeFormat(time.Now(), core.ShortDateLayout),
 				Dimension: []GetAnalyticsDataDimension{SKUDimension, DayDimension},
 				Metrics:   []GetAnalyticsDataFilterMetric{HistViewPDP},
 				Sort: []GetAnalyticsDataSort{