oper.gi: add detail to DigraphDisjointUnion error message

digraphs · Nov 29, 2019 · 49a9331 · 49a9331
1 parent 08e6a29
commit 49a9331
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Showing 2 changed files with 7 additions and 7 deletions.
diff --git a/gap/oper.gi b/gap/oper.gi
@@ -410,7 +410,7 @@ function(arg)
   if not IsList(arg) or IsEmpty(arg)
       or not ForAll(arg, IsDigraphByOutNeighboursRep) then
     ErrorNoReturn("the arguments must be digraphs by out-neighbours, or a ",
-                  "single list of digraphs by out-neighbours,");
+                  "single non-empty list of digraphs by out-neighbours,");
   fi;
 
   D := arg[1];

diff --git a/tst/standard/oper.tst b/tst/standard/oper.tst
@@ -876,14 +876,14 @@ gap> gr2 := CompleteDigraph(100);
 gap> DigraphDisjointUnion(gr) = gr;
 true
 gap> DigraphDisjointUnion([[]]);
-Error, the arguments must be digraphs by out-neighbours, or a single list of d\
-igraphs by out-neighbours,
+Error, the arguments must be digraphs by out-neighbours, or a single non-empty\
+ list of digraphs by out-neighbours,
 gap> DigraphDisjointUnion([gr], [gr]);
-Error, the arguments must be digraphs by out-neighbours, or a single list of d\
-igraphs by out-neighbours,
+Error, the arguments must be digraphs by out-neighbours, or a single non-empty\
+ list of digraphs by out-neighbours,
 gap> DigraphDisjointUnion(gr, Group(()));
-Error, the arguments must be digraphs by out-neighbours, or a single list of d\
-igraphs by out-neighbours,
+Error, the arguments must be digraphs by out-neighbours, or a single non-empty\
+ list of digraphs by out-neighbours,
 gap> DigraphDisjointUnion(gr, gr);
 <immutable digraph with 2000 vertices, 2000 edges>
 gap> DigraphDisjointUnion([gr2, gr2]);