Testfile: make non-executable

CONTRIBUTING

@@ -90,26 +90,44 @@ notice:
  *     USE OR OTHER DEALINGS IN THE SOFTWARE.
  */
 
-When writing code, make sure lines never exceed 80 characters in width when
-using four-character-wide indentation steps.
+Make sure lines never exceed 80 columns in width when using four-character
+indentation steps. This helps contributors with smaller screens, those using
+side-by-side editor windows or panes, and those who have no text wrapping in
+their editor or terminal.
 
-For usage text and help messages, please do not implement a -h option. Just
-print usage information when any erroneous option is specified. Follow the
-NetBSD style guide for usage text output format [1].
+For usage text and help messages, do not implement a -h option. Instead, print
+usage information when any erroneous option is specified. Follow the NetBSD
+style guide for the usage text’s output format [1].
 
-If committing a new source file for a utility, format the commit message like
-this:
+[1] <http://cvsweb.netbsd.org/bsdweb.cgi/~checkout~/src/share/misc/style>
 
-$ git commit -m 'tool(1): <information>'
+If committing a new source file, format the commit message following these
+guidelines:
+
+$ git commit -m 'tool(1): add feature x'
 
 If committing a new library or header file:
 
-$ git commit -m 'library(1): <information>'
+$ git commit -m 'library(3): fix overflow'
+$ git commit -m 'header.h(3): add header.h(3)'
+
+If committing a new manual page:
+
+$ git commit -m 'tool.1: add author details'
 
 If modifying some other file or directory:
 
-$ git commit -m 'README: clarification'
-$ git commit -m 'tests: posix: fixed bug #47'
-$ git commit -m 'docs: tool(1): added author information'
+$ git commit -m 'README: clarify'
+$ git commit -m 'tests/posix: fix bug #47'
 
-etc.
+For multiple of these:
+
+$ git commit -m 'Makefile, tool(1): add tool(1)'
+$ git commit -m 'tool(1): add tool(1); library(3), library.3: add library(3)'
+$ git commit -m 'tool(1): fix #42 & add feature x'
+
+Commit messages should be written in the present tense.
+
+--
+This work © 2023–2024 by Emma Tebibyte is licensed under CC BY-SA 4.0. To view a
+copy of this license, visit <http://creativecommons.org/licenses/by-sa/4.0/>

Makefile

@@ -14,6 +14,7 @@
 PREFIX=/usr/local
 
 CC=cc
+MAKE=make
 RUSTC=rustc
 
 .PHONY: all
@@ -42,6 +43,7 @@ install: dist
 test: build
 	tests/posix-compat.sh
 	$(RUSTC) --test src/getopt-rs/lib.rs -o build/test/getopt
+	$(MAKE) -f Testfile
 
 build/o/libsysexits.rlib: build
 	# bandage solution until bindgen(1) gets stdin support

Testfile

@@ -0,0 +1,78 @@
+#!/usr/bin/env make
+# Copyright (c) 2024 DTB <trinity@trinity.moe>
+# SPDX-License-Identifier: FSFAP
+#
+# Copying and distribution of this file, with or without modification, are
+# permitted in any medium without royalty provided the copyright notice and this
+# notice are preserved.  This file is offered as-is, without any warranty.
+
+BIN = build/bin
+MAKE = make -B
+
+DEFENDANTS = dj false intcmp strcmp true
+.PHONY: all $(DEFENDANTS)
+all: $(DEFENDANTS)
+
+$(BIN)/dj:
+	$(MAKE) dj
+
+$(BIN)/false:
+	$(MAKE) false
+
+$(BIN)/intcmp:
+	$(MAKE) intcmp
+
+$(BIN)/strcmp:
+	$(MAKE) strcmp
+
+$(BIN)/true:
+	$(MAKE) true
+
+dj: $(BIN)/dj $(BIN)/strcmp
+	sh -c "! $(BIN)/dj -h"
+	# This test is theoretically Linux-dependent; write(2) should return -1 on
+	# error.
+	# Right now dj(1) interprets the return value of write(2) as the amount of
+	# bytes written. This can decrement the stored quantity of bytes written,
+	# which is an int, so doesn't underflow but goes negative. dj(1) tries to
+	# again to write(2) if an error occurs in which no bytes are written, so in
+	# total two write(2)s are attempted and so the written byte quantity is -2.
+	# This is a bug and will change, but for now is at least documented.
+	sh -ec "\
+		$(BIN)/dj -Hi /dev/zero -o /dev/full \
+		| xargs -I out $(BIN)/strcmp '1+0 > 0+0; 1024 > -2' out"
+	# Read nothing from /dev/null, write nothing to /dev/null.
+	sh -ec "\
+		$(BIN)/dj -Hi /dev/null -o /dev/null \
+		| xargs -I out $(BIN)/strcmp '0+0 > 0+0; 0 > 0' out"
+
+false: $(BIN)/false
+	sh -c "! $(BIN)/false"
+	sh -c "! $(BIN)/false -h"
+
+intcmp: $(BIN)/intcmp
+	$(BIN)/intcmp -e   3 3 3
+	$(BIN)/intcmp -g   3 2 1
+	$(BIN)/intcmp -l   1 2 3
+	$(BIN)/intcmp -ge  3 3 1
+	$(BIN)/intcmp -le  1 3 3
+	$(BIN)/intcmp -gl  1 2 3
+	$(BIN)/intcmp -egl 3 1 1 2
+	sh -c "! $(BIN)/intcmp -e   1 2 3"
+	sh -c "! $(BIN)/intcmp -g   1 3 3"
+	sh -c "! $(BIN)/intcmp -l   3 3 1"
+	sh -c "! $(BIN)/intcmp -ge  1 2 3"
+	sh -c "! $(BIN)/intcmp -le  3 2 1"
+	sh -c "! $(BIN)/intcmp -gl  3 3 3"
+	sh -c "! $(BIN)/intcmp -egl foo"
+
+strcmp: $(BIN)/strcmp
+	$(BIN)/strcmp equals equals
+	sh -c "! $(BIN)/strcmp inequals equals"
+	$(BIN)/strcmp - -
+	sh -c "! $(BIN)/strcmp -h"
+	sh -c "! $(BIN)/strcmp nocmp"
+
+true:
+	$(BIN)/true
+	$(BIN)/true -h