[t/spec] Add two tests for lazy triangle reduce.

git-svn-id: http://svn.pugscode.org/pugs@30291 c213334d-75ef-0310-aa23-eaa082d1ae64

S03-metaops/reduce.t

@@ -1,7 +1,7 @@
 use v6;
 use Test;
 
-plan 81;
+plan 83;
 
 =begin pod
 
@@ -186,6 +186,11 @@ is( ([<] 42), Bool::True, "[<] 42 returns true");
 is( ~([\<] 42), "1", "[\<] 42 returns '1'");
 ok( ([\<] 42) ~~ Iterable, "[\<] 42 returns something Iterable");
 
+is( ([\*] 1..*).batch(10).join(', '), '1, 2, 6, 24, 120, 720, 5040, 40320, 362880, 3628800', 
+    'triangle reduce is lazy');
+is( ([\R~] 'a'..*).batch(8).join(', '), 'a, ba, cba, dcba, edcba, fedcba, gfedcba, hgfedcba',
+    'triangle reduce is lazy');
+
 # RT #65164 (TODO: implement [^^])
 #?rakudo skip 'implement [^^]'
 {