Treat NO_COLOR="" the same as unset

The docs say

> Command-line software which adds ANSI color to its output by default
> should check for a NO_COLOR environment variable that, when present
> and not an empty string (regardless of its value), prevents the
> addition of ANSI color.

but we were not checking for the empty string.

Link: https://no-color.org/
Link: https://github.com/sharkdp/fd/pull/1421

2 files changed, 32 insertions, 0 deletions

diff --git a/tests/bfs/nocolor_env_empty.out b/tests/bfs/nocolor_env_empty.out
new file mode 100644
index 0000000..a439814
--- /dev/null
+++ b/tests/bfs/nocolor_env_empty.out
@@ -0,0 +1,27 @@
+$'rainbow/\e[1m'
+$'rainbow/\e[1m/'$'\e[0m'
+rainbow
+rainbow/exec.sh
+rainbow/socket
+rainbow/broken
+rainbow/chardev_link
+rainbow/link.txt
+rainbow/sticky_ow
+rainbow/sgid
+rainbow/pipe
+rainbow/ow
+rainbow/sugid
+rainbow/suid
+rainbow/sticky
+rainbow/file.dat
+rainbow/file.txt
+rainbow/lower.gz
+rainbow/lower.tar
+rainbow/lower.tar.gz
+rainbow/lu.tar.GZ
+rainbow/mh1
+rainbow/mh2
+rainbow/ul.TAR.gz
+rainbow/upper.GZ
+rainbow/upper.TAR
+rainbow/upper.TAR.GZ
diff --git a/tests/bfs/nocolor_env_empty.sh b/tests/bfs/nocolor_env_empty.sh
new file mode 100644
index 0000000..0ffc046
--- /dev/null
+++ b/tests/bfs/nocolor_env_empty.sh
@@ -0,0 +1,5 @@
+command -v unbuffer &>/dev/null || skip
+
+NO_COLOR= bfs_pty rainbow >"$OUT"
+sort_output
+diff_output