diff --git a/tests/lib/Makefile.inc b/tests/lib/Makefile.inc
index 9a62476..3b8e93c 100644
--- a/tests/lib/Makefile.inc
+++ b/tests/lib/Makefile.inc
@@ -40,6 +40,7 @@
 tests-y += cbfs-lookup-no-mcache-test
 tests-y += cbfs-lookup-has-mcache-test
 tests-y += lzma-test
+tests-y += ux_locales-test
 
 lib-test-srcs += tests/lib/lib-test.c
 
@@ -241,3 +242,11 @@
 lzma-test-srcs += tests/stubs/console.c
 lzma-test-srcs += src/lib/lzma.c
 lzma-test-srcs += src/lib/lzmadecode.c
+
+ux_locales-test-srcs += tests/lib/ux_locales-test.c
+ux_locales-test-srcs += tests/stubs/console.c
+ux_locales-test-srcs += src/lib/ux_locales.c
+ux_locales-test-mocks += _cbfs_alloc \
+			cbfs_unmap \
+			vb2api_get_locale_id \
+			vboot_get_context
diff --git a/tests/lib/ux_locales-test.c b/tests/lib/ux_locales-test.c
new file mode 100644
index 0000000..d5eeef7
--- /dev/null
+++ b/tests/lib/ux_locales-test.c
@@ -0,0 +1,261 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <cbfs.h>
+#include <stdbool.h>
+#include <string.h>
+#include <tests/test.h>
+#include <ux_locales.h>
+#include <vb2_api.h>
+
+#define DATA_DEFAULT                                                                           \
+	(                                                                                      \
+		"\x01"  /* Version. */                                                         \
+		"name_1\x00"  /* name_1, langs = [0, 2, 30]. */                                \
+		"0\x00translation_1_0\x00"                                                     \
+		"2\x00translation_1_2\x00"                                                     \
+		"30\x00translation_1_30\x00"                                                   \
+		"\x01"                                                                         \
+		"name_15\x00"  /* name_15, langs = [4, 25, 60]. */                             \
+		"4\x00translation_15_4\x00"                                                    \
+		"25\x00translation_15_25\x00"                                                  \
+		"60\x00translation_15_60\x00"                                                  \
+		"\x01"                                                                         \
+		"name_20\x00"  /* name_20, langs = [8]. */                                     \
+		"8\x00translation_20_8\x00"                                                    \
+		"\x01"                                                                         \
+	)
+const unsigned char data_default[] = DATA_DEFAULT;
+
+/*
+ * The data must be set in the setup function and might be used in cbfs related functions.
+ * The size of the data must be recorded because the data contains the null character \x00.
+ *
+ * Note that sizeof(DATA_DEFAULT) will count the '\0' at the end, so DATA_DEFAULT_SIZE, i.e.
+ * the real data size must be minus one.
+ */
+#define DATA_DEFAULT_SIZE (sizeof(DATA_DEFAULT) - 1)
+
+#define MAX_DATA_SIZE (DATA_DEFAULT_SIZE + 1)
+struct {
+	unsigned char raw[MAX_DATA_SIZE];
+	size_t size;
+} data;
+
+/* Mock functions. */
+void cbfs_unmap(void *mapping)
+{
+	/* No-op. */
+}
+
+/* We can't mock cbfs_ro_map() directly as it's a static inline function. */
+void *_cbfs_alloc(const char *name, cbfs_allocator_t allocator, void *arg,
+		  size_t *size_out, bool force_ro, enum cbfs_type *type)
+{
+	/* Mock a successful CBFS mapping. */
+	if (mock_type(bool)) {
+		*size_out = data.size;
+		return data.raw;
+	}
+	*size_out = 0;
+	return NULL;
+}
+
+uint32_t vb2api_get_locale_id(struct vb2_context *ctx)
+{
+	return mock_type(uint32_t);
+}
+
+struct vb2_context *vboot_get_context(void)
+{
+	static struct vb2_context vboot2_ctx;
+	return &vboot2_ctx;
+}
+
+/* Test states for test_ux_locales_get_text with valid CBFS data. */
+struct ux_locales_test_state {
+	const char *name;
+	uint32_t lang_id;
+	const char *expect;
+};
+
+/* Setup and teardown functions. */
+static int setup_default(void **state)
+{
+	void *ret;
+	/* Setup the mocked cbfs region data. */
+	data.size = DATA_DEFAULT_SIZE;
+	ret = memset(data.raw, 0xff, MAX_DATA_SIZE);
+	if (!ret)
+		return 1;
+	ret = memcpy(data.raw, data_default, data.size);
+	if (!ret)
+		return 1;
+	return 0;
+}
+
+static int setup_bad_version(void **state)
+{
+	int ret = setup_default(state);
+	if (ret)
+		return ret;
+	/* Modify the version byte. */
+	data.raw[0] = ~data.raw[0];
+	return 0;
+}
+
+static int teardown_unmap(void **state)
+{
+	/* We need to reset the cached_state in src/lib/ux_locales.c. */
+	ux_locales_unmap();
+	return 0;
+}
+
+/* Test items. */
+static void test_ux_locales_get_text(void **state)
+{
+	struct ux_locales_test_state *s = *state;
+	const char *ret;
+
+	will_return(_cbfs_alloc, true);
+	will_return(vb2api_get_locale_id, s->lang_id);
+	ret = ux_locales_get_text(s->name);
+	if (s->expect) {
+		assert_non_null(ret);
+		assert_string_equal(ret, s->expect);
+	} else {
+		assert_null(ret);
+	}
+}
+
+static void test_ux_locales_bad_cbfs(void **state)
+{
+	will_return(_cbfs_alloc, false);
+	will_return_maybe(vb2api_get_locale_id, 0);
+	assert_null(ux_locales_get_text("name_1"));
+}
+
+static void test_ux_locales_bad_version(void **state)
+{
+	will_return(_cbfs_alloc, true);
+	will_return(vb2api_get_locale_id, 0);
+	assert_null(ux_locales_get_text("name_1"));
+}
+
+static void test_ux_locales_two_calls(void **state)
+{
+	const char *ret;
+
+	/* We do not need to ensure that we cached the cbfs region. */
+	will_return_always(_cbfs_alloc, true);
+
+	/* Call #1: read (15, 60). */
+	will_return(vb2api_get_locale_id, 60);
+	ret = ux_locales_get_text("name_15");
+	assert_non_null(ret);
+	assert_string_equal(ret, "translation_15_60");
+
+	/* Call #2: read (1, 0). */
+	will_return(vb2api_get_locale_id, 0);
+	ret = ux_locales_get_text("name_1");
+	assert_non_null(ret);
+	assert_string_equal(ret, "translation_1_0");
+}
+
+static void test_ux_locales_null_terminated(void **state)
+{
+	will_return_always(_cbfs_alloc, true);
+	will_return_always(vb2api_get_locale_id, 8);
+
+	/* Verify the access to the very last text. */
+	assert_non_null(ux_locales_get_text("name_20"));
+
+	/* Modify the last 2 bytes from "\x00\x01" to "XX" and unmap, */
+	data.raw[data.size - 1] = 'X';
+	data.raw[data.size - 2] = 'X';
+	ux_locales_unmap();
+
+	/* The last few characters are now changed so that the data is not NULL terminated.
+	   This will prevent us from accessing the last text. */
+	assert_null(ux_locales_get_text("name_20"));
+}
+
+/*
+ * This macro helps test ux_locales_get_text with `_name` and `_lang_id`.
+ * If `_expect` is NULL, then the function should not find anything.
+ * Otherwise, the function should find the corresponding expect value.
+ */
+#define _UX_LOCALES_GET_TEXT_TEST(_test_name, _name, _lang_id, _expect)                        \
+	((struct CMUnitTest) {                                                                 \
+		.name = _test_name,                                                            \
+		.test_func = test_ux_locales_get_text,                                         \
+		.setup_func = setup_default,                                                   \
+		.teardown_func = teardown_unmap,                                               \
+		.initial_state = &(struct ux_locales_test_state)                               \
+			{                                                                      \
+				.name = _name,                                                 \
+				.lang_id = _lang_id,                                           \
+				.expect = _expect,                                             \
+			},                                                                     \
+	})
+
+/*
+ * When exporting test results to xml files, cmocka doesn't escape double quotes for test names.
+ * Therefore, double quotes in CMUnitTest.name will lead to invalid xml files, causing build
+ * failure (with JUNIT_OUTPUT=y). As a result, we can only use _expect for CMUnitTest.name in
+ * the macro, but not #_expect.
+ */
+#define UX_LOCALES_GET_TEXT_FOUND_TEST(_name, _lang_id, _expect)                               \
+	(_UX_LOCALES_GET_TEXT_TEST                                                             \
+		(                                                                              \
+			(                                                                      \
+				"test_ux_locales_get_text_found(name=" _name                   \
+				", lang_id=" #_lang_id ", expect=" _expect ")"                 \
+			),                                                                     \
+			_name, _lang_id, _expect                                               \
+		))
+
+#define UX_LOCALES_GET_TEXT_NOT_FOUND_TEST(_name, _lang_id)                                    \
+	(_UX_LOCALES_GET_TEXT_TEST                                                             \
+		(                                                                              \
+			(                                                                      \
+				"test_ux_locales_get_text_not_found(name=" _name               \
+				", lang_id=" #_lang_id ")"                                     \
+			),                                                                     \
+			_name, _lang_id, NULL                                                  \
+		))
+
+int main(void)
+{
+	const struct CMUnitTest tests[] = {
+		/* Get text successfully. */
+		UX_LOCALES_GET_TEXT_FOUND_TEST("name_1", 0, "translation_1_0"),
+		/* Get text with name and id both in the middle. */
+		UX_LOCALES_GET_TEXT_FOUND_TEST("name_15", 25, "translation_15_25"),
+		/* Ensure we check the whole string of 'name'.
+		   ('name_2' is the prefix of 'name_20') */
+		UX_LOCALES_GET_TEXT_NOT_FOUND_TEST("name_2", 3),
+		/* Ensure we check the whole string of 'lang_id'.
+		   (id:'2' is the prefix of id:'25' in 'name_15') */
+		UX_LOCALES_GET_TEXT_NOT_FOUND_TEST("name_15", 2),
+		/* Ensure we will fallback to 0. */
+		UX_LOCALES_GET_TEXT_FOUND_TEST("name_1", 7, "translation_1_0"),
+		/* Do not search for locale id with unmatched name. */
+		UX_LOCALES_GET_TEXT_NOT_FOUND_TEST("name_15", 8),
+		/* Validity check of lang_id > 100. We will fallback to 0. */
+		UX_LOCALES_GET_TEXT_FOUND_TEST("name_1", 100, "translation_1_0"),
+		/* cbfs not found. */
+		cmocka_unit_test_setup_teardown(test_ux_locales_bad_cbfs, setup_default,
+						teardown_unmap),
+		/* Bad version. */
+		cmocka_unit_test_setup_teardown(test_ux_locales_bad_version, setup_bad_version,
+						teardown_unmap),
+		/* Read multiple times. */
+		cmocka_unit_test_setup_teardown(test_ux_locales_two_calls, setup_default,
+						teardown_unmap),
+		/* Validity check of NULL terminated. */
+		cmocka_unit_test_setup_teardown(test_ux_locales_null_terminated,
+						setup_default, teardown_unmap),
+	};
+
+	return cb_run_group_tests(tests, NULL, NULL);
+}