diff --git a/nselib/bits.lua b/nselib/bits.lua
index 6eb4438ec..b62016820 100644
--- a/nselib/bits.lua
+++ b/nselib/bits.lua
@@ -10,6 +10,7 @@
 
 local assert = assert
 local error = error
+local unittest = require "unittest"
 
 local _ENV = {}
 
@@ -54,31 +55,25 @@ function arshift(a, b)
         return a >> b
     end
 end
-do
-    local function test8 (a, b)
-        local r = reverse(a, 8)
-        if r ~= b then
-            error(("0x%02X: expected 0x%02X, got 0x%02X"):format(a, b, r))
-        end
-    end
-    test8(0x00, 0x00)
-    test8(0x01, 0x80)
-    test8(0x80, 0x01)
-    test8(0xff, 0xff)
-    test8(0x88, 0x11)
-    test8(0x5c, 0x3a)
 
-    local function test32 (a, b)
-        local r = reverse(a, 32)
-        if r ~= b then
-            error(("0x%08X: expected 0x%08X, got 0x%08X"):format(a, b, r))
-        end
-    end
-    test32(0x00000000, 0x00000000)
-    test32(0x00000001, 0x80000000)
-    test32(0x80000000, 0x00000001)
-    test32(0xffffffff, 0xffffffff)
-    test32(0x22221234, 0x2c484444)
+if not unittest.testing() then
+  return _ENV
 end
 
+local equal = unittest.equal
+
+test_suite = unittest.TestSuite:new()
+test_suite:add_test(equal(reverse(0x00, 8), 0x00), "reverse 8-bit number")
+test_suite:add_test(equal(reverse(0x01, 8), 0x80), "reverse 8-bit number")
+test_suite:add_test(equal(reverse(0x80, 8), 0x01), "reverse 8-bit number")
+test_suite:add_test(equal(reverse(0xff, 8), 0xff), "reverse 8-bit number")
+test_suite:add_test(equal(reverse(0x88, 8), 0x11), "reverse 8-bit number")
+test_suite:add_test(equal(reverse(0x5c, 8), 0x3a), "reverse 8-bit number")
+
+test_suite:add_test(equal(reverse(0x00000000, 32), 0x00000000), "reverse 32-bit number")
+test_suite:add_test(equal(reverse(0x00000001, 32), 0x80000000), "reverse 32-bit number")
+test_suite:add_test(equal(reverse(0x80000000, 32), 0x00000001), "reverse 32-bit number")
+test_suite:add_test(equal(reverse(0xffffffff, 32), 0xffffffff), "reverse 32-bit number")
+test_suite:add_test(equal(reverse(0x22221234, 32), 0x2c484444), "reverse 32-bit number")
+
 return _ENV