Add a simple FIFO unit test that test wrap around and push, pop and
peek for both fifo8 and fifo32.

Signed-off-by: Octavian Purdila <tavip@google.com>
---
 tests/unit/test-fifo.c | 97 ++++++++++++++++++++++++++++++++++++++++++
 tests/unit/meson.build |  1 +
 2 files changed, 98 insertions(+)
 create mode 100644 tests/unit/test-fifo.c

diff --git a/tests/unit/test-fifo.c b/tests/unit/test-fifo.c
new file mode 100644
index 0000000000..3e6f007229
--- /dev/null
+++ b/tests/unit/test-fifo.c
@@ -0,0 +1,97 @@
+/*
+ * QEMU FIFO testing
+ *
+ * Copyright (C) 2024 Google LLC
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+
+#include "qemu/fifo8.h"
+#include "qemu/fifo32.h"
+
+typedef struct {
+    Fifo8 fifo8;
+    Fifo32 fifo32;
+} TestFixture;
+
+#define FIFO_SIZE 13
+
+/*
+ * Test fixture initialization.
+ */
+static void set_up(TestFixture *f, gconstpointer data)
+{
+    int n = (uintptr_t) data;
+
+    fifo8_create(&f->fifo8, n);
+    fifo32_create(&f->fifo32, n);
+}
+
+static void tear_down(TestFixture *f, gconstpointer user_data)
+{
+    fifo8_destroy(&f->fifo8);
+    fifo32_destroy(&f->fifo32);
+}
+
+static void test_push_pop_batch(TestFixture *f, int n)
+{
+    uint8_t i;
+
+    /* push and check peek */
+    for (i = 0; i < n; i++) {
+        uint8_t val8 = i;
+        uint32_t val32 = i | ((i + 1) << 8) | ((i + 2) << 16) | ((i + 3) << 24);
+
+        fifo8_push(&f->fifo8, val8);
+        if (i == 0) {
+            g_assert(*fifo8_peek_buf(&f->fifo8, 1, NULL) == val8);
+        }
+
+        fifo32_push(&f->fifo32, val32);
+        if (i == 0) {
+            g_assert(fifo32_peek(&f->fifo32) == val32);
+        }
+    }
+
+    /* check peek and pop */
+    for (i = 0; i < n; i++) {
+        uint8_t val8 = i;
+        uint32_t val32 = i | ((i + 1) << 8) | ((i + 2) << 16) | ((i + 3) << 24);
+
+        g_assert(*fifo8_peek_buf(&f->fifo8, 1, NULL) == val8);
+        g_assert(fifo8_pop(&f->fifo8) == val8);
+
+        g_assert(fifo32_peek(&f->fifo32) == val32);
+        g_assert(fifo32_pop(&f->fifo32) == val32);
+    }
+}
+
+/* max n should be less then 256 - 3 */
+static void wrap_around_test(TestFixture *f, gconstpointer user_data)
+{
+    int n = (uintptr_t) user_data;
+    const int cycles = 3;
+
+    for (int i = 0; i < cycles; i++) {
+        test_push_pop_batch(f, n / 2 + 1);
+    }
+}
+
+/* mock-ups */
+void *vmstate_info_buffer;
+uint32_t vmstate_info_uint32;
+
+int main(int argc, char **argv)
+{
+    g_test_init(&argc, &argv, NULL);
+
+    g_test_add("/fifo/wrap-around", TestFixture, (gconstpointer)FIFO_SIZE,
+               set_up, wrap_around_test, tear_down);
+
+    return g_test_run();
+}
diff --git a/tests/unit/meson.build b/tests/unit/meson.build
index 26c109c968..397f2503f8 100644
--- a/tests/unit/meson.build
+++ b/tests/unit/meson.build
@@ -47,6 +47,7 @@ tests = {
   'test-logging': [],
   'test-qapi-util': [],
   'test-interval-tree': [],
+  'test-fifo': [],
 }
 
 if have_system or have_tools
-- 
2.46.0.295.g3b9ea8a38a-goog