ash: add a few tests from hush-vars/*

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 10 insertions, 4 deletions

diff --git a/shell/hush_test/hush-vars/param_expand_alt.tests b/shell/hush_test/hush-vars/param_expand_alt.tests
index 3b646b142..c9c4249af 100755
--- a/shell/hush_test/hush-vars/param_expand_alt.tests
+++ b/shell/hush_test/hush-vars/param_expand_alt.tests
@@ -1,9 +1,15 @@
-# first try some invalid patterns (do in subshell due to parsing error)
-"$THIS_SH" -c 'echo ${+}  ; echo moo'
-"$THIS_SH" -c 'echo ${:+} ; echo moo'
+# First try some invalid patterns. Do in subshell due to parsing error.
+# (set argv0 to "SHELL" to avoid "/path/to/shell: blah" in error messages)
+"$THIS_SH" -c 'echo ${+}  ; echo moo' SHELL
+"$THIS_SH" -c 'echo ${:+} ; echo moo' SHELL
 
-# now some funky ones. (bash doesn't accept ${#+})
+# now some funky ones.
+# ${V+word} "if V unset, then substitute nothing, else substitute word"
+# ${V:+word} "if V unset or '', then substitute nothing, else substitute word"
+# bash doesn't accept ${#+}. ash prints 0 (not $#).
 echo _${#+}_ _${#:+}_
+# Forms with non-empty word work as expected in both ash and bash.
+echo _${#+z}_ _${#:+z}_
 
 # now some valid ones
 set --