Octave: error() must be called with an argument

Examples/test-suite/octave/template_ns_runme.m

@@ -3,19 +3,19 @@ p1 = pairii(2,3);
 p2 = pairii(p1);
 
 if (p2.first != 2)
-    error
+    error("failed");
 endif
 if (p2.second != 3)
-    error
+    error("failed");
 endif
 
 p3 = pairdd(3.5,2.5);
 p4 = pairdd(p3);
 
 if (p4.first != 3.5)
-    error
+    error("failed");
 endif
 
 if (p4.second != 2.5)
-    error
+    error("failed");
 endif