added testcase

format/format.go

@@ -2,32 +2,41 @@ package format
 
 import (
 	"fmt"
-	"math"
 )
 
 const (
 	Thousand = 1000
 	Million  = Thousand * 1000
 	Billion  = Million * 1000
+	Trillion = Billion * 1000
 )
 
 func HumanNumber(b uint64) string {
 	switch {
+	case b >= Trillion:
+		number := float64(b) / Trillion
+		return fmt.Sprintf("%sT", DecimalPlace(number))
 	case b >= Billion:
 		number := float64(b) / Billion
-		if number == math.Floor(number) {
+		return fmt.Sprintf("%sB", DecimalPlace(number))
-			return fmt.Sprintf("%.0fB", number) // no decimals if whole number
-		}
-		return fmt.Sprintf("%.1fB", number) // one decimal if not a whole number
 	case b >= Million:
 		number := float64(b) / Million
-		if number == math.Floor(number) {
+		return fmt.Sprintf("%sM", DecimalPlace(number))
-			return fmt.Sprintf("%.0fM", number) // no decimals if whole number
-		}
-		return fmt.Sprintf("%.2fM", number) // two decimals if not a whole number
 	case b >= Thousand:
-		return fmt.Sprintf("%.0fK", float64(b)/Thousand)
+		number := float64(b) / Thousand
+		return fmt.Sprintf("%sK", DecimalPlace(number))
 	default:
 		return fmt.Sprintf("%d", b)
 	}
 }
+
+func DecimalPlace(number float64) string {
+	switch {
+	case number >= 100:
+		return fmt.Sprintf("%.0f", number)
+	case number >= 10:
+		return fmt.Sprintf("%.1f", number)
+	default:
+		return fmt.Sprintf("%.2f", number)
+	}
+}

format/format_test.go

@@ -13,14 +13,15 @@ func TestHumanNumber(t *testing.T) {
 
 	testCases := []testCase{
 		{0, "0"},
-		{1000000, "1M"},
+		{1000000, "1.00M"},
 		{125000000, "125M"},
-		{500500000, "500.50M"},
+		{500500000, "500M"},
-		{500550000, "500.55M"},
+		{500550000, "501M"},
-		{1000000000, "1B"},
+		{1000000000, "1.00B"},
-		{2800000000, "2.8B"},
+		{2800000000, "2.80B"},
-		{2850000000, "2.9B"},
+		{2850000000, "2.85B"},
-		{1000000000000, "1000B"},
+		{28550000000, "28.6B"},
+		{1000000000000, "1.00T"},
 	}
 
 	for _, tc := range testCases {