diff --git a/roaring/fuzz_test.go b/roaring/fuzz_test.go
index c951b412e..50a1492a2 100644
--- a/roaring/fuzz_test.go
+++ b/roaring/fuzz_test.go
@@ -8,16 +8,24 @@ func TestUnmarshalBinary(t *testing.T) {
 	b := NewBitmap()
 	confirmedCrashers := []struct {
 		cr []byte
+		expected string
 	} {
-		{cr : []byte(":000000")},
-		{cr : []byte("<000000000000000")},
+		{
+			cr : []byte(":0\x000\x01\x00\x00\x000000"),					//":000000"
+			expected : "reading roaring header: malformed bitmap, key-cardinality slice overruns buffer at 12",
+		},				
+		{
+			cr : []byte("<0\x000\x00\x00\x00\x00000000000000" +
+			"0"),														//"<000000000000000"
+			expected : "unmarshaling as pilosa roaring: too big",
+		},		
 	}
 
 	for _, crash := range confirmedCrashers {
 		err := b.UnmarshalBinary(crash.cr)
-		if err != nil {
-			t.Error("Known crasher failed.")
-		}
+		if err.Error() != crash.expected {
+			t.Errorf("Expected: %s, Got: %s", crash.expected, err)
+		} 
 	}
 	
 }
\ No newline at end of file