Add a test case for external functions validation

ttcn/TestCodec/TestCodec_ExternalFunctions.ttcn

+module TestCodec_ExternalFunctions {
+
+  // LibCommon
+  import from LibCommon_BasicTypesAndValues all;
+  import from LibCommon_DataStrings all;
+
+  // LibItsCommon
+  import from LibItsCommon_Functions all;
+  
+  // TestCodec
+  import from TestCodec_TestAndSystem all;
+
+  testcase tc_f_computePositionUsingDistance() runs on TCType system TCType {
+    var Int32 v_latitude;
+    var Int32 v_longitude;
+    
+    fx_computePositionUsingDistance(
+            300000000, 
+            400000000, 
+            8.0, 
+            300,
+            v_latitude,
+            v_longitude
+        );
+    log("v_latitude= ", v_latitude);
+    log("v_longitude= ", v_longitude);
+    if (v_latitude != 300000359) {
+      setverdict(fail, "Wrong expected latitude");
+    } else if (v_longitude != 399999281) {
+      setverdict(fail, "Wrong expected longitude");
+    } else {
+      setverdict(pass);
+    }
+  }
+
+  control {
+    execute(tc_f_computePositionUsingDistance());
+  }
+  
+} // End of module TestCodec_ExternalFunctions