tests: Fix crash when stderr is redirected

bash uses fileno(stderr) to keep track of $COLUMNS.  With stderr
redirected, $COLUMNS will be unset, leading to

    $ ./tests/tests.sh 2> >(cat)
    ./tests/tests.sh: line 635: COLUMNS: unbound variable

Fix it by using $(tput cols) if $COLUMNS is unset, which is almost
POSIX.

Link: https://www.austingroupbugs.net/view.php?id=1053

1 files changed, 7 insertions, 1 deletions

diff --git a/tests/tests.sh b/tests/tests.sh
index 639822a..3fdf49b 100755
--- a/tests/tests.sh
+++ b/tests/tests.sh
@@ -630,9 +630,15 @@ BOL='\n'
 EOL='\n'
 
 function update_eol() {
+    # Bash gets $COLUMNS from stderr, so if it's redirected use tput instead
+    local cols="${COLUMNS-}"
+    if [ -z "$cols" ]; then
+        cols=$(tput cols)
+    fi
+
     # Put the cursor at the last column, then write a space so the next
     # character will wrap
-    EOL="\\033[${COLUMNS}G "
+    EOL="\\033[${cols}G "
 }
 
 if [ "$VERBOSE_TESTS" ]; then