Add tests for free monoids

tst/testinstall/monofree.tst

@@ -0,0 +1,52 @@
+#############################################################################
+##
+#W monofree.tst
+##
+gap> START_TEST("monofree.tst");
+gap> M := FreeMonoid(0);
+<free monoid on the generators [ ]>
+gap> IsFreeMonoid(M); IsTrivial(M); IsWholeFamily(M);
+true
+true
+true
+gap> M2 := M / []; 
+<fp monoid on the generators [ ]>
+gap> F := FreeMonoid(2);
+<free monoid on the generators [ m1, m2 ]>
+gap> IsWholeFamily( F );
+true
+gap> IsFinite( F );
+false
+gap> Size( F );
+infinity
+gap> One(F);
+<identity ...>
+gap> gens := GeneratorsOfMonoid(F);
+[ m1, m2 ]
+gap> a := gens[1];; b := gens[2];;
+gap> firstfifty:=[];;
+gap> iter:= Iterator(F);;
+gap> for i in [ 1 .. 50 ] do
+> Add( firstfifty, NextIterator( iter ) );
+> od;
+gap> Collected(List(firstfifty,Length));
+[ [ 0, 1 ], [ 1, 2 ], [ 2, 4 ], [ 3, 8 ], [ 4, 16 ], [ 5, 19 ] ]
+gap> IsDoneIterator( iter );
+false
+gap> enum:= Enumerator(F);;
+gap> first50:=List( [ 1 .. 50 ], x -> enum[x] );;
+gap> List( first50, x -> Position( enum, x ) ) = [ 1 .. 50 ];
+true
+
+#
+gap> ForAll([0,1,2,3,infinity], n -> (n < infinity) = IsFinitelyGeneratedMonoid(FreeMonoid(n)));
+true
+gap> ForAll([0,1,2,3,infinity], n -> (n < 2) = IsCommutative(FreeMonoid(n)));
+true
+
+#
+gap> STOP_TEST( "grpfree.tst", 330000);
+
+#############################################################################
+##
+#E