Reapply "feat(loyalty): EnakPoint & EnakCoin" (#32)

This reverts commit 4e24f9bbb0.

internal/models/loyalty_test.go

@@ -0,0 +1,32 @@
+package models
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestLoyaltyCashbackPercent(t *testing.T) {
+	assert.Equal(t, 1.0, LoyaltyCashbackPercent(1, 1, 100))
+	assert.Equal(t, 0.1, LoyaltyCashbackPercent(1, 1, 1000))
+	assert.Equal(t, 0.33, LoyaltyCashbackPercent(1, 1, 300), "rounded to two decimals")
+	assert.Equal(t, 0.67, LoyaltyCashbackPercent(2, 1, 300), "rounded, not cut")
+	assert.Equal(t, 0.0, LoyaltyCashbackPercent(1, 1, 0))
+}
+
+func TestNewLoyaltySettingsImpact(t *testing.T) {
+	before := OrganizationLoyaltySettings{PointValue: 1, Exchange: LoyaltyExchangeSettings{CoinAmount: 1, PointAmount: 1}}
+	after := OrganizationLoyaltySettings{PointValue: 100, Exchange: LoyaltyExchangeSettings{CoinAmount: 10, PointAmount: 1}}
+
+	got := NewLoyaltySettingsImpact(50000, 105, before, after)
+	assert.Equal(t, LoyaltySettingsImpact{
+		OutstandingPoints: 50000, OutstandingCoins: 105,
+		PointValueBefore: 1, PointValueAfter: 100,
+		PointRupiahBefore: 50000, PointRupiahAfter: 5000000,
+		CoinsAsPointsBefore: 105, CoinsAsPointsAfter: 10, // floor(105 / 10)
+		CoinRupiahBefore: 105, CoinRupiahAfter: 1000,
+	}, got)
+
+	same := NewLoyaltySettingsImpact(10, 10, before, before)
+	assert.Equal(t, same.PointRupiahBefore, same.PointRupiahAfter)
+}