Return empty table instead of error if load is called with empty params

ngcp/dp.lua

@@ -18,14 +18,14 @@ NGCPDomainPrefs_MT = { __index = NGCPDomainPrefs }
 
     function NGCPDomainPrefs:caller_load(uuid)
         if not uuid then
-            error("uuid is empty")
+            return {}
         end
         return NGCPDomainPrefs._load(self,"caller",uuid)
     end
 
     function NGCPDomainPrefs:callee_load(uuid)
         if not uuid then
-            error("uuid is empty")
+            return {}
         end
         return NGCPDomainPrefs._load(self,"callee",uuid)
     end

ngcp/up.lua

@@ -18,14 +18,14 @@ NGCPUserPrefs_MT = { __index = NGCPUserPrefs }
 
     function NGCPUserPrefs:caller_load(uuid)
         if not uuid then
-            error("uuid is empty")
+            return {}
         end
         return NGCPUserPrefs._load(self,"caller",uuid)
     end
 
     function NGCPUserPrefs:callee_load(uuid)
         if not uuid then
-            error("uuid is empty")
+            return {}
         end
         return NGCPUserPrefs._load(self,"callee",uuid)
     end

tests/ngcp_dp.lua

@@ -72,12 +72,12 @@ TestNGCPDomainPrefs = {} --class
 
     function TestNGCPDomainPrefs:test_caller_load_empty()
         assertTrue(self.d.config)
-        assertError(self.d.caller_load, nil)
+        assertEquals(self.d:caller_load(), {})
     end
 
     function TestNGCPDomainPrefs:test_callee_load_empty()
         assertTrue(self.d.config)
-        assertError(self.d.callee_load, nil)
+        assertEquals(self.d:callee_load(), {})
     end
 
     function TestNGCPDomainPrefs:test_caller_load()

tests/ngcp_pp.lua

@@ -72,12 +72,12 @@ TestNGCPPeerPrefs = {} --class
 
     function TestNGCPPeerPrefs:test_caller_load_empty()
         assertTrue(self.d.config)
-        assertEquals(self.d.caller_load(), nil)
+        assertEquals(self.d:caller_load(), {})
     end
 
     function TestNGCPPeerPrefs:test_callee_load_empty()
         assertTrue(self.d.config)
-        assertEquals(self.d.callee_load(), nil)
+        assertEquals(self.d:callee_load(), {})
     end
 
     function TestNGCPPeerPrefs:test_caller_load()

tests/ngcp_up.lua

@@ -67,12 +67,12 @@ TestNGCPUserPrefs = {} --class
 
     function TestNGCPUserPrefs:test_caller_load_empty()
         assertTrue(self.d.config)
-        assertError(self.d.caller_load, nil)
+        assertEquals(self.d:caller_load(), {})
     end
 
     function TestNGCPUserPrefs:test_callee_load_empty()
         assertTrue(self.d.config)
-        assertError(self.d.callee_load, nil)
+        assertEquals(self.d:callee_load(), {})
     end
 
     function TestNGCPUserPrefs:test_init()