diff --git a/libx52io/test_io_strings.c b/libx52io/test_io_strings.c
new file mode 100644
index 0000000..128b1af
--- /dev/null
+++ b/libx52io/test_io_strings.c
@@ -0,0 +1,191 @@
+/*
+ * Saitek X52 IO driver - io string parse tests
+ *
+ * Copyright (C) 2012-2020 Nirenjan Krishnan (nirenjan@nirenjan.org)
+ *
+ * SPDX-License-Identifier: GPL-2.0-only WITH Classpath-exception-2.0
+ */
+
+#include <stdarg.h>
+#include <stddef.h>
+#include <setjmp.h>
+#include <cmocka.h>
+
+#include "libx52io.h"
+
+static void lower_ascii_only(char *dst, const char *src)
+{
+    for (; *src; src++, dst++) {
+        unsigned char c = (unsigned char)*src;
+
+        if (c >= 'A' && c <= 'Z') {
+            c = (unsigned char)(c - 'A' + 'a');
+        }
+        *dst = (char)c;
+    }
+    *dst = '\0';
+}
+
+static void test_axis_round_trip(void **state)
+{
+    libx52io_axis a;
+    libx52io_axis out;
+
+    (void)state;
+
+    for (a = LIBX52IO_AXIS_X; a < LIBX52IO_AXIS_MAX; a++) {
+        const char *s = libx52io_axis_to_str(a);
+
+        assert_non_null(s);
+        assert_int_equal(LIBX52IO_SUCCESS, libx52io_axis_from_str(s, &out));
+        assert_int_equal(a, out);
+        assert_ptr_equal(s, libx52io_axis_to_str(out));
+    }
+}
+
+static void test_button_round_trip(void **state)
+{
+    libx52io_button b;
+    libx52io_button out;
+
+    (void)state;
+
+    for (b = LIBX52IO_BTN_TRIGGER; b < LIBX52IO_BUTTON_MAX; b++) {
+        const char *s = libx52io_button_to_str(b);
+
+        assert_non_null(s);
+        assert_int_equal(LIBX52IO_SUCCESS, libx52io_button_from_str(s, &out));
+        assert_int_equal(b, out);
+        assert_ptr_equal(s, libx52io_button_to_str(out));
+    }
+}
+
+static void test_axis_from_str_invalid(void **state)
+{
+    libx52io_axis out;
+
+    (void)state;
+
+    assert_int_equal(LIBX52IO_ERROR_INVALID, libx52io_axis_from_str("", &out));
+    assert_int_equal(LIBX52IO_ERROR_INVALID, libx52io_axis_from_str("ABS_", &out));
+    assert_int_equal(LIBX52IO_ERROR_INVALID, libx52io_axis_from_str("ABS_XX", &out));
+    assert_int_equal(LIBX52IO_ERROR_INVALID, libx52io_axis_from_str("abs_x", &out));
+    assert_int_equal(LIBX52IO_ERROR_INVALID, libx52io_axis_from_str("BTN_FIRE", &out));
+}
+
+static void test_button_from_str_invalid(void **state)
+{
+    libx52io_button out;
+
+    (void)state;
+
+    assert_int_equal(LIBX52IO_ERROR_INVALID, libx52io_button_from_str("", &out));
+    assert_int_equal(LIBX52IO_ERROR_INVALID, libx52io_button_from_str("BTN_", &out));
+    assert_int_equal(LIBX52IO_ERROR_INVALID,
+        libx52io_button_from_str("BTN_FIRE_EXTRA", &out));
+    assert_int_equal(LIBX52IO_ERROR_INVALID, libx52io_button_from_str("btn_fire", &out));
+    assert_int_equal(LIBX52IO_ERROR_INVALID, libx52io_button_from_str("ABS_X", &out));
+}
+
+static void test_from_str_null_args(void **state)
+{
+    libx52io_axis ax;
+    libx52io_button btn;
+
+    (void)state;
+
+    assert_int_equal(LIBX52IO_ERROR_INVALID, libx52io_axis_from_str(NULL, &ax));
+    assert_int_equal(LIBX52IO_ERROR_INVALID, libx52io_axis_from_str("ABS_X", NULL));
+    assert_int_equal(LIBX52IO_ERROR_INVALID, libx52io_button_from_str(NULL, &btn));
+    assert_int_equal(LIBX52IO_ERROR_INVALID, libx52io_button_from_str("BTN_A", NULL));
+}
+
+static void test_axis_from_str_nocase(void **state)
+{
+    libx52io_axis a;
+    libx52io_axis out;
+    char buf[64];
+
+    (void)state;
+
+    for (a = LIBX52IO_AXIS_X; a < LIBX52IO_AXIS_MAX; a++) {
+        const char *s = libx52io_axis_to_str(a);
+
+        assert_non_null(s);
+        lower_ascii_only(buf, s);
+        assert_int_equal(LIBX52IO_SUCCESS, libx52io_axis_from_str_nocase(buf, &out));
+        assert_int_equal(a, out);
+    }
+
+    assert_int_equal(LIBX52IO_SUCCESS,
+        libx52io_axis_from_str_nocase("aBs_hAtX", &out));
+    assert_int_equal(LIBX52IO_AXIS_HATX, out);
+}
+
+static void test_button_from_str_nocase(void **state)
+{
+    libx52io_button b;
+    libx52io_button out;
+    char buf[64];
+
+    (void)state;
+
+    for (b = LIBX52IO_BTN_TRIGGER; b < LIBX52IO_BUTTON_MAX; b++) {
+        const char *s = libx52io_button_to_str(b);
+
+        assert_non_null(s);
+        lower_ascii_only(buf, s);
+        assert_int_equal(LIBX52IO_SUCCESS, libx52io_button_from_str_nocase(buf, &out));
+        assert_int_equal(b, out);
+    }
+
+    assert_int_equal(LIBX52IO_SUCCESS,
+        libx52io_button_from_str_nocase("BtN_t1_dN", &out));
+    assert_int_equal(LIBX52IO_BTN_T1_DN, out);
+}
+
+static void test_from_str_nocase_invalid(void **state)
+{
+    libx52io_axis ax;
+    libx52io_button btn;
+
+    (void)state;
+
+    assert_int_equal(LIBX52IO_ERROR_INVALID, libx52io_axis_from_str_nocase("", &ax));
+    assert_int_equal(LIBX52IO_ERROR_INVALID, libx52io_axis_from_str_nocase("abs_xx", &ax));
+    assert_int_equal(LIBX52IO_ERROR_INVALID, libx52io_button_from_str_nocase("", &btn));
+    assert_int_equal(LIBX52IO_ERROR_INVALID,
+        libx52io_button_from_str_nocase("btn_fire_extra", &btn));
+}
+
+static void test_from_str_nocase_null_args(void **state)
+{
+    libx52io_axis ax;
+    libx52io_button btn;
+
+    (void)state;
+
+    assert_int_equal(LIBX52IO_ERROR_INVALID, libx52io_axis_from_str_nocase(NULL, &ax));
+    assert_int_equal(LIBX52IO_ERROR_INVALID, libx52io_axis_from_str_nocase("abs_x", NULL));
+    assert_int_equal(LIBX52IO_ERROR_INVALID, libx52io_button_from_str_nocase(NULL, &btn));
+    assert_int_equal(LIBX52IO_ERROR_INVALID, libx52io_button_from_str_nocase("btn_a", NULL));
+}
+
+int main(void)
+{
+    const struct CMUnitTest tests[] = {
+        cmocka_unit_test(test_axis_round_trip),
+        cmocka_unit_test(test_button_round_trip),
+        cmocka_unit_test(test_axis_from_str_invalid),
+        cmocka_unit_test(test_button_from_str_invalid),
+        cmocka_unit_test(test_from_str_null_args),
+        cmocka_unit_test(test_axis_from_str_nocase),
+        cmocka_unit_test(test_button_from_str_nocase),
+        cmocka_unit_test(test_from_str_nocase_invalid),
+        cmocka_unit_test(test_from_str_nocase_null_args),
+    };
+
+    cmocka_set_message_output(CM_OUTPUT_TAP);
+    cmocka_run_group_tests(tests, NULL, NULL);
+    return 0;
+}