From 3f650b6851ca358e7c9e95f95d71382731d23627 Mon Sep 17 00:00:00 2001
From: Dennis Bonke <admin@dennisbonke.com>
Date: Wed, 9 Oct 2024 01:49:24 +0200
Subject: [PATCH] tests/posix: Add tests for swab

---
 tests/meson.build  |  1 +
 tests/posix/swab.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 63 insertions(+)
 create mode 100644 tests/posix/swab.c

diff --git a/tests/meson.build b/tests/meson.build
index bbc0cd6491..ec1b860fce 100644
--- a/tests/meson.build
+++ b/tests/meson.build
@@ -98,6 +98,7 @@ all_test_cases = [
 	'posix/mkstemp',
 	'posix/waitid',
 	'posix/usershell',
+	'posix/swab',
 	'glibc/getopt',
 	'glibc/ffsl-ffsll',
 	'glibc/error_message_count',
diff --git a/tests/posix/swab.c b/tests/posix/swab.c
new file mode 100644
index 0000000000..12515c0d9e
--- /dev/null
+++ b/tests/posix/swab.c
@@ -0,0 +1,62 @@
+#include <assert.h>
+#include <unistd.h>
+
+void test_swab_even_bytes() {
+	uint8_t input[] = {0x01, 0x02, 0x03, 0x04};
+    uint8_t output[4];
+    
+    swab(input, output, sizeof(input));
+
+    assert(output[0] == 0x02);
+    assert(output[1] == 0x01);
+    assert(output[2] == 0x04);
+    assert(output[3] == 0x03);
+}
+
+void test_swab_odd_bytes() {
+	uint8_t input[] = {0x01, 0x02, 0x03, 0x04, 0x05};
+    uint8_t output[5];
+    
+    swab(input, output, sizeof(input));
+
+    assert(output[0] == 0x02);
+    assert(output[1] == 0x01);
+    assert(output[2] == 0x04);
+    assert(output[3] == 0x03);
+
+    // Last byte is UB, assume unchanged?
+    assert(output[4] == 0x05);
+}
+
+void test_swab_negative_bytes() {
+	uint8_t input[] = {0x01, 0x02, 0x03, 0x04};
+    uint8_t output[4];
+    
+    swab(input, output, -1); // Should change nothing
+
+    assert(output[0] == 0x01);
+    assert(output[1] == 0x02);
+    assert(output[2] == 0x03);
+    assert(output[3] == 0x04);
+}
+
+void test_swab_zero_bytes() {
+	uint8_t input[] = {0x01, 0x02, 0x03, 0x04};
+    uint8_t output[4];
+    
+    swab(input, output, 0); // Should change nothing
+
+    assert(output[0] == 0x01);
+    assert(output[1] == 0x02);
+    assert(output[2] == 0x03);
+    assert(output[3] == 0x04);
+}
+
+int main() {
+	test_swab_even_bytes();
+	test_swab_odd_bytes();
+	test_swab_negative_bytes();
+	test_swab_zero_bytes();
+
+	return 0;
+}