feat: add affiliate invite rebate flow and admin rebate-rate setting

backend/internal/service/affiliate_service_test.go

@@ -0,0 +1,59 @@
+//go:build unit
+
+package service
+
+import (
+	"context"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+type affiliateSettingRepoStub struct {
+	value string
+	err   error
+}
+
+func (s *affiliateSettingRepoStub) Get(context.Context, string) (*Setting, error) { return nil, s.err }
+func (s *affiliateSettingRepoStub) GetValue(context.Context, string) (string, error) {
+	if s.err != nil {
+		return "", s.err
+	}
+	return s.value, nil
+}
+func (s *affiliateSettingRepoStub) Set(context.Context, string, string) error { return s.err }
+func (s *affiliateSettingRepoStub) GetMultiple(context.Context, []string) (map[string]string, error) {
+	if s.err != nil {
+		return nil, s.err
+	}
+	return map[string]string{}, nil
+}
+func (s *affiliateSettingRepoStub) SetMultiple(context.Context, map[string]string) error {
+	return s.err
+}
+func (s *affiliateSettingRepoStub) GetAll(context.Context) (map[string]string, error) {
+	if s.err != nil {
+		return nil, s.err
+	}
+	return map[string]string{}, nil
+}
+func (s *affiliateSettingRepoStub) Delete(context.Context, string) error { return s.err }
+
+func TestAffiliateRebateRatePercentSemantics(t *testing.T) {
+	t.Parallel()
+
+	svc := &AffiliateService{settingRepo: &affiliateSettingRepoStub{value: "1"}}
+	rate := svc.loadAffiliateRebateRatePercent(context.Background())
+	require.Equal(t, 1.0, rate)
+
+	svc.settingRepo = &affiliateSettingRepoStub{value: "0.2"}
+	rate = svc.loadAffiliateRebateRatePercent(context.Background())
+	require.Equal(t, 0.2, rate)
+}
+
+func TestMaskEmail(t *testing.T) {
+	t.Parallel()
+	require.Equal(t, "a***@g***.com", maskEmail("alice@gmail.com"))
+	require.Equal(t, "x***@d***", maskEmail("x@domain"))
+	require.Equal(t, "", maskEmail(""))
+}