cmd/tests: Add tests for variables substrings

[Frédéric Delanoy]

---
 programs/cmd/tests/test_builtins.cmd     |   13 +++++++++++++
 programs/cmd/tests/test_builtins.cmd.exp |   10 ++++++++++
 2 files changed, 23 insertions(+), 0 deletions(-)

diff --git a/programs/cmd/tests/test_builtins.cmd b/programs/cmd/tests/test_builtins.cmd
index 0d2f983..dfdc2d2 100644
--- a/programs/cmd/tests/test_builtins.cmd
+++ b/programs/cmd/tests/test_builtins.cmd
@@ -192,6 +192,19 @@ echo P%ERRORLEVEL%
 echo %ERRORLEVEL%S
 echo P%ERRORLEVEL%S
 
+echo ------------ Testing variable substrings --------------
+set VAR=qwerty
+echo %VAR:~0,1%
+echo %VAR:~0,3%
+echo %VAR:~2,2%
+echo '%VAR:~-2,3%'
+echo '%VAR:~-2,1%'
+echo %VAR:~2,-1%
+echo %VAR:~2,-3%
+echo '%VAR:~-2,-4%'
+echo %VAR:~-3,-2%
+set VAR=
+
 echo ------------ Testing variable delayed expansion --------------
 rem NT4 doesn't support this
 echo ...default mode (load-time expansion)
diff --git a/programs/cmd/tests/test_builtins.cmd.exp b/programs/cmd/tests/test_builtins.cmd.exp
index 1138485..a3714f2 100644
--- a/programs/cmd/tests/test_builtins.cmd.exp
+++ b/programs/cmd/tests/test_builtins.cmd.exp
@@ -182,6 +182,16 @@ ERRORLEVEL
 P0
 0S
 P0S
+------------ Testing variable substrings --------------
+q
+qwe
+er
+ at todo_wine@'ty'@or_broken@''
+'t'@or_broken@''
+ert at or_broken@qwerty
+e at or_broken@qwerty
+''@or_broken@'qwerty'
+r at or_broken@qwerty
 ------------ Testing variable delayed expansion --------------
 ...default mode (load-time expansion)
 foo
-- 
1.7.6