New tests for chmod.

The chmod fixes in the previous several commits were
caught by this.

* Makefile (tst/tests/018/chmod.ok): Set up TXR_ARGS for this
test to give it the location of the temporary file to use
as the object for testing permissions.
(tst/tests/018): Disable TXR_DBG_OPTS for new directory.

* tests/018/chmod.tl: New file.

* tests/018/chmod.expected: Likewise.

* tests/perm.tl: Likewise.

4 files changed, 47 insertions, 0 deletions

diff --git a/Makefile b/Makefile
index eef7f722..7ff11c4d 100644
--- a/Makefile
+++ b/Makefile
@@ -397,6 +397,7 @@ tst/tests/010/align-columns.ok: TXR_ARGS := tests/010/align-columns.dat
 tst/tests/010/block.ok: TXR_OPTS := -B
 tst/tests/010/reghash.ok: TXR_OPTS := -B
 tst/tests/013/maze.ok: TXR_ARGS := 20 20
+tst/tests/018/chmod.ok: TXR_ARGS := tst/tests/018/tempfile
 
 tst/tests/002/%: TXR_SCRIPT_ON_CMDLINE := y
 
@@ -407,6 +408,7 @@ tst/tests/014/%: TXR_DBG_OPTS :=
 tst/tests/015/%: TXR_DBG_OPTS :=
 tst/tests/016/%: TXR_DBG_OPTS :=
 tst/tests/017/%: TXR_DBG_OPTS :=
+tst/tests/018/%: TXR_DBG_OPTS :=
 
 TST_EXPECTED  = $(word 2,$^)
 TST_OUT = $(patsubst %.expected,tst/%.out,$(TST_EXPECTED))
diff --git a/tests/018/chmod.expected b/tests/018/chmod.expected
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/tests/018/chmod.expected
diff --git a/tests/018/chmod.tl b/tests/018/chmod.tl
new file mode 100644
index 00000000..7ae0f9b2
--- /dev/null
+++ b/tests/018/chmod.tl
@@ -0,0 +1,34 @@
+(load "../common")
+(load "../perm")
+
+(defvarl tgt [*args* 0])
+
+(defmacro mode-bits (st-mode)
+  (logand st-mode #xFFF))
+
+(defun cht (init mode expected)
+  (let ((ini (dec-perm init))
+        (exp (dec-perm expected)))
+    (chmod tgt ini)
+    (let* ((st (stat tgt))
+           (m (logand st.mode #xFFF)))
+      (unless (eql m ini)
+        (error "failed to set initial mode: expected: ~s, actual: ~s "
+               init (enc-perm m))))
+    (chmod tgt mode)
+    (let* ((st (stat tgt))
+           (m (logand st.mode #xFFF)))
+      (unless (eql m exp)
+        (error "failed to set mode: expected ~s, actual ~s"
+               expected (enc-perm m))))))
+
+(remove-path tgt)
+(with-stream (s (open-file tgt "w")))
+(umask #o022)
+
+(cht "------------" "a+strwx"           "sgtrwxrwxrwx")
+(cht "------------" "+strwx"            "sgtrwxr-xr-x")
+(cht "------------" "u+s"               "s-----------")
+(cht "------------" "g+s"               "-g----------")
+(cht "------------" "+t"                "--t---------")
+(cht "sgtrwxrwxrwx" "="                 "------------")
diff --git a/tests/perm.tl b/tests/perm.tl
new file mode 100644
index 00000000..d9df0b85
--- /dev/null
+++ b/tests/perm.tl
@@ -0,0 +1,11 @@
+(defun enc-perm (p)
+  (let ((d (digits (logior 4096 p) 2)))
+    (mapcar (do if (zerop @2) #\- @1) "sgtrwxrwxrwx" (rest d))))
+
+(defun dec-perm (s)
+  (let ((d (mapcar (do cond
+                     ((eql @1 @2) 1)
+                     ((eql #\- @2) 0)
+                     (t (error `decode-perm: invalid input @s`)))
+                   "sgtrwxrwxrwx" s)))
+    (poly 2 d)))