Add a test.

tests/02-core/03-arg-processor/90-init-required/expect.md

@@ -0,0 +1,14 @@
+## test
+
+### stderr
+```
+the-cmd: 
+the-cmd:18: Cannot use both --required and --init.
+the-cmd:19: Cannot use both --required and --init.
+the-cmd:20: Cannot use both --required and --init.
+Cannot process arguments, due to declaration errors.
+
+the-cmd -- test command
+```
+
+### exit: 1

tests/02-core/03-arg-processor/90-init-required/info.txt

@@ -0,0 +1 @@
+Test for error detection on `--init=... --required`.

tests/02-core/03-arg-processor/90-init-required/run

@@ -0,0 +1,10 @@
+#!/bin/bash
+# Copyright 2022-2023 the Bashy-lib Authors (Dan Bornstein et alia).
+# SPDX-License-Identifier: Apache-2.0
+
+[[ "$(readlink -f "$0")" =~ ^(.*/tests/) ]] && . "${BASH_REMATCH[1]}_test-init.sh" || exit 1
+
+cmd="$(this-cmd-dir)/the-cmd"
+
+call-and-log-as-test 'test' \
+    "${cmd}"

tests/02-core/03-arg-processor/90-init-required/the-cmd

@@ -0,0 +1,24 @@
+#!/bin/bash
+# Copyright 2022-2023 the Bashy-lib Authors (Dan Bornstein et alia).
+# SPDX-License-Identifier: Apache-2.0
+
+[[ "$(readlink -f "$0")" =~ ^(.*/tests/) ]] && . "${BASH_REMATCH[1]}_init.sh" || exit 1
+
+
+#
+# Argument parsing
+#
+
+define-usage $'
+    ${name} -- test command
+
+    This is a test command.
+'
+
+opt-value --required --var=var1 --init=florp some-value
+opt-choice --init=maybe --required --var=var3 yes no
+positional-arg --init=x --var=var4 --required some-position
+
+process-args "$@" || usage --short
+
+echo 'Nopers.'