Refactor expr and add another test entry that works with TEST_HOST=1 but not with the one in pending.
diff --git a/tests/expr.test b/tests/expr.test
index 1c038a5..33900d7 100644
--- a/tests/expr.test
+++ b/tests/expr.test
@@ -17,3 +17,5 @@
testing "expr * % same priority" "expr 3 \* 2 % 4" "2\n" "" ""
testing "expr = > same priority" "expr 0 = 2 \> 3" "0\n" "" ""
testing "expr > = same priority" "expr 3 \> 2 = 1" "1\n" "" ""
+testing "expr string becomes integer" "expr ab21xx : '[^0-9]*\([0-9]*\)' + 3" \
+ "24\n" "" ""