fix：修复显示负数值的问题

Author: spiritLHLS

sp/sp.go

@@ -260,8 +260,8 @@ func NearbySpeedTest() {
 		})
 		if err == nil {
 			fmt.Print(formatString("Speedtest.net", 16))
-			fmt.Print(formatString(fmt.Sprintf("%-8s", fmt.Sprintf("%.2f", NearbyServer.ULSpeed.Mbps())+" Mbps"), 16))
-			fmt.Print(formatString(fmt.Sprintf("%-8s", fmt.Sprintf("%.2f", NearbyServer.DLSpeed.Mbps())+" Mbps"), 16))
+			fmt.Print(formatString(formatMbps(NearbyServer.ULSpeed.Mbps()), 16))
+			fmt.Print(formatString(formatMbps(NearbyServer.DLSpeed.Mbps()), 16))
 			fmt.Print(formatString(NearbyServer.Latency.String(), 16))
 			fmt.Print(formatString(PacketLoss, 16))
 			fmt.Println()
@@ -371,8 +371,8 @@ func CustomSpeedTest(url, byWhat string, num int, language string) {
 				name = strings.ReplaceAll(name, "法兰克福", "Frankfurt")
 				fmt.Print(formatString(name, 16))
 			}
-			fmt.Print(formatString(fmt.Sprintf("%-8s", fmt.Sprintf("%.2f", server.ULSpeed.Mbps())+" Mbps"), 16))
-			fmt.Print(formatString(fmt.Sprintf("%-8s", fmt.Sprintf("%.2f", server.DLSpeed.Mbps())+" Mbps"), 16))
+			fmt.Print(formatString(formatMbps(server.ULSpeed.Mbps()), 16))
+			fmt.Print(formatString(formatMbps(server.DLSpeed.Mbps()), 16))
 			fmt.Print(formatString(server.Latency.String(), 16))
 			fmt.Print(formatString(PacketLoss, 16))
 			fmt.Println()

sp/utils.go

@@ -5,6 +5,7 @@ import (
 	"encoding/csv"
 	"fmt"
 	"io"
+	"math"
 	"strings"
 	"time"
 	"unicode/utf8"
@@ -272,6 +273,13 @@ func formatString(s string, width int) string {
 	return s
 }
 
+func formatMbps(value float64) string {
+	if math.IsNaN(value) || math.IsInf(value, 0) || value < 0 {
+		value = 0
+	}
+	return fmt.Sprintf("%.2f Mbps", value)
+}
+
 func ShowHead(language string) {
 	headers1 := []string{"位置", "上传速度", "下载速度", "延迟", "丢包率"}
 	headers2 := []string{"Location", "Upload Speed", "Download Speed", "Latency", "PacketLoss"}

sp/utils_test.go

@@ -0,0 +1,27 @@
+package sp
+
+import (
+	"math"
+	"testing"
+)
+
+func TestFormatMbps(t *testing.T) {
+	tests := []struct {
+		name string
+		value float64
+		want  string
+	}{
+		{name: "negative", value: -0.0001, want: "0.00 Mbps"},
+		{name: "nan", value: math.NaN(), want: "0.00 Mbps"},
+		{name: "positive", value: 293.075, want: "293.08 Mbps"},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			got := formatMbps(tc.value)
+			if got != tc.want {
+				t.Fatalf("formatMbps(%v) = %q, want %q", tc.value, got, tc.want)
+			}
+		})
+	}
+}