support multi-module (#4)

* add multimodule
* re-package modules

util/number_test.go

@@ -0,0 +1,33 @@
+package util
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestFixed(t *testing.T) {
+	for _, tc := range []struct {
+		precision        int
+		source, expected float64
+	}{
+		{3, 0, 0},
+		{3, -1, -1},
+		{3, 1.5, 1.5},
+		{3, 2.25, 2.25},
+		{3, 3.275, 3.275},
+		{3, 4.0004, 4.000},
+		{5, 5.000005, 5.00001},
+		{4, -6.00004, -6.},
+		{4, -6.00005, -6.0001},
+	} {
+		t.Run(fmt.Sprintf("%f", tc.source), func(t *testing.T) {
+			if tc.precision == 3 {
+				assert.Equal(t, tc.expected, Fixed3(tc.source))
+			} else {
+				assert.Equal(t, tc.expected, fixed(tc.source, tc.precision))
+			}
+		})
+	}
+}