Add test for prices

lib/journal/prices_test.go

@@ -0,0 +1,141 @@
+package journal
+
+import (
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+
+	"github.com/shopspring/decimal"
+)
+
+type Price struct {
+	Commodity *Commodity
+	Price     decimal.Decimal
+	Target    *Commodity
+}
+
+func TestPrices(t *testing.T) {
+	jctx := NewContext()
+	com1 := jctx.Commodity("COM1")
+	com2 := jctx.Commodity("COM2")
+
+	tests := []struct {
+		desc  string
+		input []*Price
+		want  Prices
+	}{
+		{
+			desc: "case 1",
+			input: []*Price{
+				{
+					Commodity: com1,
+					Target:    com2,
+					Price:     decimal.RequireFromString("4.0"),
+				},
+			},
+			want: Prices{
+				com2: {
+					com1: decimal.RequireFromString("4.0"),
+				},
+				com1: {
+					com2: decimal.RequireFromString("0.25"),
+				},
+			},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.desc, func(t *testing.T) {
+			got := make(Prices)
+			for _, in := range test.input {
+				got.Insert(in.Commodity, in.Price, in.Target)
+			}
+			if diff := cmp.Diff(got, test.want); diff != "" {
+				t.Fatalf("unexpected diff (+got/-want):\n%s", diff)
+			}
+		})
+	}
+}
+
+func TestNormalize(t *testing.T) {
+	jctx := NewContext()
+	com1 := jctx.Commodity("COM1")
+	com2 := jctx.Commodity("COM2")
+	com3 := jctx.Commodity("COM3")
+	// com4 := jctx.Commodity("COM2")
+
+	tests := []struct {
+		desc   string
+		input  []*Price
+		target *Commodity
+		want   NormalizedPrices
+	}{
+		{
+			desc: "case 1",
+			input: []*Price{
+				{Commodity: com1, Price: decimal.RequireFromString("4.0"), Target: com2},
+				{Commodity: com2, Price: decimal.RequireFromString("2.0"), Target: com3},
+			},
+			target: com1,
+			want: NormalizedPrices{
+				com1: decimal.RequireFromString("1"),
+				com2: decimal.RequireFromString("0.25"),
+				com3: decimal.RequireFromString("0.125"),
+			},
+		},
+		{
+			desc: "case 2",
+			input: []*Price{
+				{Commodity: com1, Price: decimal.RequireFromString("4.0"), Target: com2},
+				{Commodity: com2, Price: decimal.RequireFromString("2.0"), Target: com3},
+			},
+			target: com2,
+			want: NormalizedPrices{
+				com1: decimal.RequireFromString("4"),
+				com2: decimal.RequireFromString("1"),
+				com3: decimal.RequireFromString("0.5"),
+			},
+		},
+		{
+			desc: "case 3",
+			input: []*Price{
+				{Commodity: com1, Price: decimal.RequireFromString("4.0"), Target: com2},
+				{Commodity: com2, Price: decimal.RequireFromString("2.0"), Target: com3},
+			},
+			target: com3,
+			want: NormalizedPrices{
+				com1: decimal.RequireFromString("8"),
+				com2: decimal.RequireFromString("2"),
+				com3: decimal.RequireFromString("1"),
+			},
+		},
+		{
+			desc: "case 4",
+			input: []*Price{
+				{Commodity: com1, Price: decimal.RequireFromString("4.0"), Target: com2},
+				{Commodity: com3, Price: decimal.RequireFromString("2.0"), Target: com2},
+			},
+			target: com3,
+			want: NormalizedPrices{
+				com1: decimal.RequireFromString("2"),
+				com2: decimal.RequireFromString("0.5"),
+				com3: decimal.RequireFromString("1"),
+			},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.desc, func(t *testing.T) {
+			pr := make(Prices)
+			for _, in := range test.input {
+				pr.Insert(in.Commodity, in.Price, in.Target)
+			}
+
+			got := pr.Normalize(test.target)
+
+			if diff := cmp.Diff(test.want, got); diff != "" {
+				t.Fatalf("unexpected diff (-want/+got):\n%s", diff)
+			}
+		})
+	}
+}