refactor the code related to xtcp (#3449)

pkg/util/util/util_test.go

@@ -14,10 +14,51 @@ func TestRandId(t *testing.T) {
 	assert.Equal(16, len(id))
 }
 
+func TestRandIDWithRandLen(t *testing.T) {
+	tests := []struct {
+		name      string
+		start     int
+		end       int
+		expectErr bool
+	}{
+		{
+			name:      "start and end are equal",
+			start:     5,
+			end:       5,
+			expectErr: true,
+		},
+		{
+			name:      "start is less than end",
+			start:     5,
+			end:       10,
+			expectErr: false,
+		},
+		{
+			name:      "start is greater than end",
+			start:     10,
+			end:       5,
+			expectErr: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			assert := assert.New(t)
+			id, err := RandIDWithRandLen(tt.start, tt.end)
+			if tt.expectErr {
+				assert.Error(err)
+			} else {
+				assert.NoError(err)
+				assert.GreaterOrEqual(len(id), tt.start)
+				assert.Less(len(id), tt.end)
+			}
+		})
+	}
+}
+
 func TestGetAuthKey(t *testing.T) {
 	assert := assert.New(t)
 	key := GetAuthKey("1234", 1488720000)
-	t.Log(key)
 	assert.Equal("6df41a43725f0c770fd56379e12acf8c", key)
 }