diff --git a/ngcp/avp.lua b/ngcp/avp.lua
new file mode 100644
index 0000000..50d0441
--- /dev/null
+++ b/ngcp/avp.lua
@@ -0,0 +1,37 @@
+#!/usr/bin/env lua5.1
+
+-- class NGCPAvp
+NGCPAvp = {
+     __class__ = 'NGCPAvp'
+}
+NGCPAvp_MT = {
+    __index = NGCPAvp,
+}
+
+    function NGCPAvp:new(id)
+        local t = { id = "$(avp(s:" .. id .. "))" }
+        NGCPAvp_MT.__call = function(t, value)
+            if not value then
+                --print(table.tostring(sr.pv.vars))
+                --print(t.id)
+                return sr.pv.get(t.id)
+            elseif type(value) == "number" then
+                sr.pv.seti(t.id, value)
+            elseif type(value) == "string" then
+                sr.pv.sets(t.id, value)
+            else
+                error("value is not a number or string")
+            end
+        end
+        setmetatable( t, NGCPAvp_MT )
+        return t
+    end
+
+    function NGCPAvp:clean()
+        --print("NGCPAvp:clean")
+        --print(table.tostring(getmetatable(self)))
+        --print(table.tostring(self))
+        sr.pv.unset(self.id)
+    end
+-- class
+--EOF
\ No newline at end of file
diff --git a/tests/mocks.lua b/tests/mocks.lua
index 94bbe90..7e9376f 100644
--- a/tests/mocks.lua
+++ b/tests/mocks.lua
@@ -17,7 +17,7 @@ TestSRMock = {}
     end
 
     function TestSRMock:tearDown()
-        self.sr = nil
+        self.sr.pv.vars = {}
     end
 
     function TestSRMock:test_ini()
@@ -25,31 +25,28 @@ TestSRMock = {}
     end
 
     function TestSRMock:test_sets()
-        self.sr.pv.unset("$avp('hithere')")
-        self.sr.pv.sets("$avp('hithere')", "value")
-        assertEquals(self.sr.pv.vars["$avp('hithere')"], "value")
-        assertError(self.sr.pv.sets, "$avp('hithere')", 1)
+        self.sr.pv.sets("$(avp(s:hithere))", "value")
+        assertEquals(self.sr.pv.vars["$(avp(s:hithere))"], "value")
+        assertError(self.sr.pv.sets, "$(avp(s:hithere))", 1)
     end
 
     function TestSRMock:test_seti()
-        self.sr.pv.unset("$avp('hithere')")
-        self.sr.pv.seti("$avp('hithere')", 0)
-        assertEquals(self.sr.pv.vars["$avp('hithere')"], 0)
-        assertError(self.sr.pv.seti, "$avp('hithere')", "1")
+        self.sr.pv.seti("$(avp(s:hithere))", 0)
+        assertEquals(self.sr.pv.vars["$(avp(s:hithere))"], 0)
+        assertError(self.sr.pv.seti, "$(avp(s:hithere))", "1")
     end
 
     function TestSRMock:test_get()
         local vals = {1,2,3}
-        self.sr.pv.unset("$avp('hithere')")
-        self.sr.pv.sets("$avp('hithere')", "value")
-        assertEquals(self.sr.pv.get("$avp('hithere')"), "value")
-        self.sr.pv.unset("$avp('hithere')")
-        self.sr.pv.seti("$avp('hithere')", 1)
-        assertEquals(self.sr.pv.get("$avp('hithere')"), 1)
+        self.sr.pv.sets("$(avp(s:hithere))", "value")
+        assertEquals(self.sr.pv.get("$(avp(s:hithere))"), "value")
+        self.sr.pv.unset("$(avp(s:hithere))")
+        self.sr.pv.seti("$(avp(s:hithere))", 1)
+        assertEquals(self.sr.pv.get("$(avp(s:hithere))"), 1)
         for i=1,#vals do
-            self.sr.pv.seti("$avp('hithere')", vals[i])
+            self.sr.pv.seti("$(avp(s:hithere))", vals[i])
         end
-        local l = self.sr.pv.get("$avp('hithere')")
+        local l = self.sr.pv.get("$(avp(s:hithere))")
         assertTrue(type(l), 'table')
         --print(table.tostring(l))
         v = 1
@@ -60,20 +57,21 @@ TestSRMock = {}
     end
 
     function TestSRMock:test_unset()
-        self.sr.pv.sets("$avp('hithere')", "value")
-        self.sr.pv.unset("$avp('hithere')")
-        assertEquals(self.sr.pv.vars["$avp('hithere')"], nil)
-        self.sr.pv.unset("$avp('hithere')")
-        assertEquals(self.sr.pv.vars["$avp('hithere')"], nil)
+        self.sr.pv.sets("$(avp(s:hithere))", "value")
+        self.sr.pv.unset("$(avp(s:hithere))")
+        assertEquals(self.sr.pv.vars["$(avp(s:hithere))"], nil)
+        self.sr.pv.unset("$(avp(s:hithere))")
+        assertEquals(self.sr.pv.vars["$(avp(s:hithere))"], nil)
     end
 
     function TestSRMock:test_is_null()
-        self.sr.pv.unset("$avp('hithere')")
-        assertTrue(self.sr.pv.is_null("$avp('hithere')"))
-        self.sr.pv.sets("$avp('hithere')", "value")
-        assertFalse(self.sr.pv.is_null("$avp('hithere')"))
-        self.sr.pv.sets("$avp('hithere')", "value")
-        assertFalse(self.sr.pv.is_null("$avp('hithere')"))
+        assertTrue(self.sr.pv.is_null("$(avp(s:hithere))"))
+        self.sr.pv.unset("$(avp(s:hithere))")
+        assertTrue(self.sr.pv.is_null("$(avp(s:hithere))"))
+        self.sr.pv.sets("$(avp(s:hithere))", "value")
+        assertFalse(self.sr.pv.is_null("$(avp(s:hithere))"))
+        self.sr.pv.sets("$(avp(s:hithere))", "value")
+        assertFalse(self.sr.pv.is_null("$(avp(s:hithere))"))
     end
 ---- Control test output:
 lu = LuaUnit
diff --git a/tests/ngcp_avp.lua b/tests/ngcp_avp.lua
new file mode 100644
index 0000000..bdd271d
--- /dev/null
+++ b/tests/ngcp_avp.lua
@@ -0,0 +1,70 @@
+#!/usr/bin/env lua5.1
+require('luaunit')
+require 'mocks.sr'
+require 'ngcp.avp'
+
+sr = srMock:new()
+
+TestNGCPAvp = {} --class
+    function TestNGCPAvp:setUp()
+        self.avp = NGCPAvp:new("testid")
+    end
+
+    function TestNGCPAvp:tearDown()
+        sr.pv.vars = {}
+    end
+
+    function TestNGCPAvp:test_avp_id()
+        assertEquals(self.avp.id, "$(avp(s:testid))")
+    end
+
+    function TestNGCPAvp:test_avp_get()
+        sr.pv.sets("$(avp(s:testid))", "value")
+        assertEquals(self.avp(), "value")
+        sr.pv.sets("$(avp(s:testid))", "1")
+        assertItemsEquals(self.avp(),{"1","value"})
+    end
+
+    function TestNGCPAvp:test_avp_set()
+        local vals = {1,2,3}
+        for i=1,#vals do
+            self.avp(vals[i])
+        end
+        local l = self.avp()
+        assertTrue(type(l), 'table')
+        --print(table.tostring(l))
+        v = 1
+        for i=#vals,1,-1 do
+           assertEquals(l[i],vals[v])
+           v = v + 1 
+        end        
+    end
+
+    function TestNGCPAvp:test_avp_set2()
+        local vals = {1,2,"3"}
+        for i=1,#vals do
+            self.avp(vals[i])
+        end
+        local l = self.avp()
+        assertTrue(type(l), 'table')
+        --print(table.tostring(l))
+        v = 1
+        for i=#vals,1,-1 do
+           assertEquals(l[i],vals[v])
+           v = v + 1 
+        end        
+    end
+
+    function TestNGCPAvp:test_clean()
+        self.avp(1)
+        self.avp:clean()
+        assertFalse(self.avp())
+    end
+-- class TestNGCPAvp
+
+---- Control test output:
+lu = LuaUnit
+lu:setOutputType( "TAP" )
+lu:setVerbosity( 1 )
+lu:run()
+--EOF
\ No newline at end of file