diff --git a/test/main.lua b/test/main.lua
index 142b7301e..7ff0f0eee 100644
--- a/test/main.lua
+++ b/test/main.lua
@@ -37,7 +37,7 @@ local done_command = utils.processArgsGetopt({...}, {
         {'h', 'help', handler=function() help = true end},
         {'n', 'nocache', handler=function() nocache = true end},
         {'d', 'test_dir', hasArg=true,
-         handler=function(arg) mode_filter = arg:split(',') end},
+         handler=function(arg) test_dir = arg end},
         {'m', 'modes', hasArg=true,
          handler=function(arg) mode_filter = arg:split(',') end},
         {'t', 'tests', hasArg=true,
@@ -127,8 +127,9 @@ local function table_eq_recurse(a, b, keys, known_eq)
     return true
 end
 function expect.table_eq(a, b, comment)
-    if type(a) ~= 'table' or type(b) ~= 'table' then
-        return false, comment, 'both operands to table_eq must be tables'
+    if (type(a) ~= 'table' and type(a) ~= 'userdata') or
+            (type(b) ~= 'table' and type(b) ~= 'userdata') then
+        return false, comment, 'operands to table_eq must be tables or userdata'
     end
     local keys, known_eq = {}, {}
     local matched, keys_at_diff, diff = table_eq_recurse(a, b, keys, known_eq)
diff --git a/test/test.lua b/test/test.lua
index 6b188e766..faaaf3265 100644
--- a/test/test.lua
+++ b/test/test.lua
@@ -8,6 +8,9 @@ function test.table_eq()
     expect.true_(expect_raw.table_eq({{'a', k='val'}, 'b'},
                                      {{'a', k='val'}, 'b'}))
 
+    expect.false_(expect_raw.table_eq(nil, nil)) -- operands must be non-nil
+    expect.false_(expect_raw.table_eq({}, nil))
+    expect.false_(expect_raw.table_eq(nil, {}))
     expect.false_(expect_raw.table_eq({}, {''}))
     expect.false_(expect_raw.table_eq({''}, {}))
     expect.false_(expect_raw.table_eq({'a', {}}, {'a'}))