diff --git a/decor/speed_test.go b/decor/speed_test.go
index 02e6183..876095b 100644
--- a/decor/speed_test.go
+++ b/decor/speed_test.go
@@ -31,6 +31,14 @@
 			expected: "0b/s",
 		},
 		{
+			name:     "SizeB1024(0):%f:0b",
+			unit:     SizeB1024(0),
+			fmt:      "%f",
+			current:  0,
+			elapsed:  time.Duration(0),
+			expected: "0.000000b/s",
+		},
+		{
 			name:     "SizeB1024(0):% .2f:0b",
 			unit:     SizeB1024(0),
 			fmt:      "% .2f",
@@ -159,6 +167,14 @@
 			expected: "0b/s",
 		},
 		{
+			name:     "SizeB1000(0):%f:0b",
+			unit:     SizeB1000(0),
+			fmt:      "%f",
+			current:  0,
+			elapsed:  time.Duration(0),
+			expected: "0.000000b/s",
+		},
+		{
 			name:     "SizeB1000(0):% .2f:0b",
 			unit:     SizeB1000(0),
 			fmt:      "% .2f",