kselftest: Add basic test for probing the rust sample modules

Add new basic kselftest that checks if the available rust sample modules
can be added and removed correctly.

Signed-off-by: Laura Nao <[e-mail]>
Reviewed-by: Sergio Gonzalez Collado <[e-mail]>
Reviewed-by: Muhammad Usama Anjum <[e-mail]>
Signed-off-by: Shuah Khan <[e-mail]>

MAINTAINERS

···
 F:	rust/
 F:	samples/rust/
 F:	scripts/*rust*
+F:	tools/testing/selftests/rust/
 K:	\b(?i:rust)\b
 
 RXRPC SOCKETS (AF_RXRPC)

tools/testing/selftests/Makefile

···
 TARGETS += rlimits
 TARGETS += rseq
 TARGETS += rtc
+TARGETS += rust
 TARGETS += seccomp
 TARGETS += sgx
 TARGETS += sigaltstack

tools/testing/selftests/rust/Makefile

···
+# SPDX-License-Identifier: GPL-2.0
+TEST_PROGS += test_probe_samples.sh
+
+include ../lib.mk

tools/testing/selftests/rust/config

···
+CONFIG_RUST=y
+CONFIG_SAMPLES=y
+CONFIG_SAMPLES_RUST=y
+CONFIG_SAMPLE_RUST_MINIMAL=m
+CONFIG_SAMPLE_RUST_PRINT=m

tools/testing/selftests/rust/test_probe_samples.sh

···
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# Copyright (c) 2023 Collabora Ltd
+#
+# This script tests whether the rust sample modules can
+# be added and removed correctly.
+#
+DIR="$(dirname "$(readlink -f "$0")")"
+
+KTAP_HELPERS="${DIR}/../kselftest/ktap_helpers.sh"
+if [ -e "$KTAP_HELPERS" ]; then
+    source "$KTAP_HELPERS"
+else
+    echo "$KTAP_HELPERS file not found [SKIP]"
+    exit 4
+fi
+
+rust_sample_modules=("rust_minimal" "rust_print")
+
+ktap_print_header
+
+for sample in "${rust_sample_modules[@]}"; do
+    if ! /sbin/modprobe -n -q "$sample"; then
+        ktap_skip_all "module $sample is not found in /lib/modules/$(uname -r)"
+        exit "$KSFT_SKIP"
+    fi
+done
+
+ktap_set_plan "${#rust_sample_modules[@]}"
+
+for sample in "${rust_sample_modules[@]}"; do
+    if /sbin/modprobe -q "$sample"; then
+        /sbin/modprobe -q -r "$sample"
+        ktap_test_pass "$sample"
+    else
+        ktap_test_fail "$sample"
+    fi
+done
+
+ktap_finished