first version

internal/features/spread_test.go

@@ -0,0 +1,13 @@
+package features
+
+import "testing"
+
+func TestSpread(t *testing.T) {
+	got, err := Spread(dec("99"), dec("101"), dec("0.1"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !got.Mid.Equal(dec("100")) || !got.SpreadBps.Equal(dec("200")) || !got.HalfSpreadBps.Equal(dec("100")) || !got.TickBps.Equal(dec("10")) {
+		t.Fatalf("unexpected spread: %+v", got)
+	}
+}