diff --git a/src/audio/mux/mux_generic.c b/src/audio/mux/mux_generic.c
index 85b73638c..34a0f3c4d 100644
--- a/src/audio/mux/mux_generic.c
+++ b/src/audio/mux/mux_generic.c
@@ -26,9 +26,9 @@
  * \param[in] offset Offset in source buffer.
  * \param[in] mask Routing bitmask for calculating output sample.
  */
-static inline int32_t calc_sample_s16le(struct comp_buffer *source,
-					uint8_t num_ch, uint32_t offset,
-					uint8_t mask)
+UT_STATIC inline int32_t calc_sample_s16le(struct comp_buffer *source,
+					   uint8_t num_ch, uint32_t offset,
+					   uint8_t mask)
 {
 	int32_t sample = 0;
 	int16_t *src;
diff --git a/src/include/sof/audio/mux.h b/src/include/sof/audio/mux.h
index a50d000ee..3c55fcae7 100644
--- a/src/include/sof/audio/mux.h
+++ b/src/include/sof/audio/mux.h
@@ -90,6 +90,9 @@ demux_func demux_get_processing_function(struct comp_dev *dev);
 #ifdef UNIT_TEST
 void sys_comp_mux_init(void);
 
+int32_t calc_sample_s16le(struct comp_buffer *source,
+			  uint8_t num_ch, uint32_t offset,
+			  uint8_t mask);
 int32_t calc_sample_s24le(struct comp_buffer *source,
 			  uint8_t num_ch, uint32_t offset,
 			  uint8_t mask);
diff --git a/test/cmocka/src/audio/mux/CMakeLists.txt b/test/cmocka/src/audio/mux/CMakeLists.txt
index d1eb820da..6fe5d59dc 100644
--- a/test/cmocka/src/audio/mux/CMakeLists.txt
+++ b/test/cmocka/src/audio/mux/CMakeLists.txt
@@ -36,6 +36,12 @@ cmocka_test(
 	mock.c
 )
 
+cmocka_test(
+	mux_generic_calc_sample_s16le
+	mux_generic_calc_sample_s16le.c
+	mock.c
+)
+
 cmocka_test(
 	mux_generic_calc_sample_s24le
 	mux_generic_calc_sample_s24le.c
diff --git a/test/cmocka/src/audio/mux/mux_generic_calc_sample_s16le.c b/test/cmocka/src/audio/mux/mux_generic_calc_sample_s16le.c
new file mode 100644
index 000000000..252947313
--- /dev/null
+++ b/test/cmocka/src/audio/mux/mux_generic_calc_sample_s16le.c
@@ -0,0 +1,128 @@
+// SPDX-License-Identifier: BSD-3-Clause
+//
+// Copyright(c) 2019 Intel Corporation. All rights reserved.
+//
+// Author: Daniel Bogdzia <danielx.bogdzia@linux.intel.com>
+//         Janusz Jankowski <janusz.jankowski@linux.intel.com>
+
+#include <sof/audio/component.h>
+#include <sof/audio/mux.h>
+
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <setjmp.h>
+#include <stdlib.h>
+#include <cmocka.h>
+
+struct test_data {
+	const char *name;
+	uint32_t channels;
+	uint8_t mask;
+	int16_t *input;
+	struct comp_buffer *buffer;
+	int32_t expected_result;
+};
+
+static int16_t input_samples[][PLATFORM_MAX_CHANNELS] = {
+	{ 0x1, 0x2, 0x4, 0x8,
+	  0x10, 0x20, 0x40, 0x80, },
+	{ 0x100, 0x200, 0x400, 0x800,
+	  0x1000, 0x2000, 0x4000, 0x8000, },
+	{ 0x8000, 0xf000, 0x8000, 0xf000,
+	  0xf000, 0x8000, 0xf000, 0x8000, },
+};
+
+#define TEST_CASE(channels, mask, input_index) \
+	{ ("test_calc_sample_s16le_ch_" #channels "_mask_" #mask \
+	   "_input_" #input_index), channels, mask, \
+	 input_samples[input_index], NULL, 0 }
+
+static struct test_data test_cases[] = {
+	TEST_CASE(1, 0x0, 0),
+	TEST_CASE(1, 0x0, 1),
+	TEST_CASE(1, 0x0, 2),
+	TEST_CASE(1, 0x1, 0),
+	TEST_CASE(1, 0x1, 1),
+	TEST_CASE(1, 0x1, 2),
+	TEST_CASE(2, 0x0, 0),
+	TEST_CASE(2, 0x0, 1),
+	TEST_CASE(2, 0x0, 2),
+	TEST_CASE(2, 0x1, 0),
+	TEST_CASE(2, 0x1, 2),
+	TEST_CASE(2, 0x2, 0),
+	TEST_CASE(2, 0x2, 2),
+	TEST_CASE(2, 0x3, 0),
+	TEST_CASE(2, 0x3, 2),
+	TEST_CASE(3, 0x1, 1),
+	TEST_CASE(3, 0x7, 1),
+	TEST_CASE(5, 0x4, 1),
+	TEST_CASE(5, 0x12, 1),
+	TEST_CASE(7, 0x10, 1),
+	TEST_CASE(7, 0x11, 1),
+	TEST_CASE(8, 0x0f, 1),
+	TEST_CASE(8, 0x0f, 2),
+	TEST_CASE(8, 0x10, 0),
+	TEST_CASE(8, 0x11, 0),
+	TEST_CASE(8, 0xf0, 1),
+	TEST_CASE(8, 0xf0, 2),
+	TEST_CASE(8, 0xff, 1),
+	TEST_CASE(8, 0xff, 2),
+};
+
+static void test_calc_sample(void **state)
+{
+	struct test_data *td = *((struct test_data **)state);
+
+	int32_t ret =  calc_sample_s16le(td->buffer,
+					 td->channels,
+					 0,
+					 td->mask);
+
+	assert_int_equal(ret, td->expected_result);
+}
+
+static int setup(void **state)
+{
+	struct test_data *td = *((struct test_data **)state);
+	int ch;
+
+	td->buffer = calloc(1, sizeof(struct comp_buffer));
+	td->buffer->r_ptr = td->input;
+
+	td->expected_result = 0;
+
+	for (ch = 0; ch < td->channels; ++ch) {
+		if (td->mask & BIT(ch))
+			td->expected_result += td->input[ch];
+	}
+
+	return 0;
+}
+
+static int teardown(void **state)
+{
+	struct test_data *td = *((struct test_data **)state);
+
+	free(td->buffer);
+
+	return 0;
+}
+
+int main(void)
+{
+	int i;
+	struct CMUnitTest tests[ARRAY_SIZE(test_cases)];
+
+	for (i = 0; i < ARRAY_SIZE(test_cases); ++i) {
+		tests[i].name = test_cases[i].name;
+		tests[i].test_func = test_calc_sample;
+		tests[i].initial_state = &test_cases[i];
+		tests[i].setup_func = setup;
+		tests[i].teardown_func = teardown;
+	}
+
+	cmocka_set_message_output(CM_OUTPUT_TAP);
+
+	return cmocka_run_group_tests(tests, NULL, NULL);
+}