incdec: Get backward incrementing working in all cases

Set up the proper condition to get the start index of the number just
before point.

1 files changed, 6 insertions, 0 deletions

diff --git a/t/100-increment-decrement.t b/t/100-increment-decrement.t
index 1345dfe..dd0df5c 100644
--- a/t/100-increment-decrement.t
+++ b/t/100-increment-decrement.t
@@ -67,4 +67,10 @@ is(
 	'increments the third triple-digit integer with point at position 13 backward'
 );
 
+is(
+	incdec::incdec('test 12 19 555 64', 14, 1),
+	'test 12 19 556 64',
+	'increments the third triple-digit integer with point at position 14 backward'
+);
+
 done_testing;