Add more tests for socket.try/protect

test/excepttest.lua

@@ -1,6 +1,31 @@
 local socket = require("socket")
-try = socket.newtry(function()
-    print("finalized!!!")
+
+local finalizer_called
+
+local func = socket.protect(function(err, ...)
+    local try = socket.newtry(function()
+        finalizer_called = true
+        error("ignored")
+    end)
+
+    if err then
+        return error(err, 0)
+    else
+        return try(...)
+    end
 end)
-try = socket.protect(try)
-print(try(nil, "it works"))
+
+local ret1, ret2, ret3 = func(false, 1, 2, 3)
+assert(not finalizer_called, "unexpected finalizer call")
+assert(ret1 == 1 and ret2 == 2 and ret3 == 3, "incorrect return values")
+
+ret1, ret2, ret3 = func(false, false, "error message")
+assert(finalizer_called, "finalizer not called")
+assert(ret1 == nil and ret2 == "error message" and ret3 == nil, "incorrect return values")
+
+local err = {key = "value"}
+ret1, ret2 = pcall(func, err)
+assert(not ret1, "error not rethrown")
+assert(ret2 == err, "incorrect error rethrown")
+
+print("OK")