test: ztest: Add base-2 logarithm unit test converted from CMock

This patch converts 1 existing math advanced function unit test from
CMock/Unity to Zephyr's Ztest framework, maintaining the same test
coverage and functionality:

- test_math_arithmetic_base2log_fixed: Fixed-point base-2 logarithm

Original test converted from
sof/test/cmocka/src/math/arithmetic/base2_logarithm.c authored by:
- Shriram Shastry <malladi.sastry@linux.intel.com>

The converted test validates the same base2_logarithm() function from
src/math/base2log.c as the original CMock test, ensuring no regression
in test coverage during the migration to Ztest framework. Reference
tables and tolerance values are preserved to maintain identical test
accuracy and validation criteria.

Test validates 100 uniformly distributed input values across the full
uint32_t range using MATLAB-generated reference data with fixed-point
arithmetic:
- Input values: Q32.0 format (unsigned 32-bit integers)
- Results: Q16.16 format
- Reference: MATLAB log2() function results
- Tolerance: max error 0.0000236785999981, THD -92.5128795787487235

This continues the SOF unit test migration from CMock to Zephyr Ztest
framework as part of the math/advanced/functions test suite.

Signed-off-by: Tomasz Leman <tomasz.m.leman@intel.com>

Author: tmleman

test/ztest/unit/math/advanced/functions/CMakeLists.txt

@@ -29,7 +29,9 @@ target_compile_definitions(app PRIVATE
 
 target_sources(app PRIVATE
 	test_scalar_power_ztest.c
+	test_base2_logarithm_ztest.c
 	${SOF_ROOT}/src/math/power.c
+	${SOF_ROOT}/src/math/base2log.c
 )
 
 # Apply SOF relative path definitions for proper compilation

test/ztest/unit/math/advanced/functions/test_base2_logarithm_ztest.c

@@ -0,0 +1,76 @@
+// SPDX-License-Identifier: BSD-3-Clause
+//
+// Copyright(c) 2026 Intel Corporation. All rights reserved.
+//
+// These contents may have been developed with support from one or more Intel-operated
+// generative artificial intelligence solutions.
+//
+// Converted from CMock to Ztest
+//
+// Original test from sof/test/cmocka/src/math/arithmetic/base2_logarithm.c
+// Author: Shriram Shastry <malladi.sastry@linux.intel.com>
+
+#include <zephyr/ztest.h>
+#include <sof/audio/format.h>
+#include <sof/math/log.h>
+#include <math.h>
+#include <rtos/string.h>
+
+/* Test data tables from MATLAB-generated reference */
+#include "log2_tables.h"
+
+/* 'Error[max] = 0.0000236785999981,THD(-dBc) = -92.5128795787487235' */
+#define CMP_TOLERANCE 0.0000236785691029f
+
+/* testvector in Q32.0 */
+static const uint32_t uv[100] = {
+	1ULL,	 43383509ULL,   86767017ULL,   130150525ULL, 173534033ULL, 216917541ULL,
+	260301049ULL, 303684557ULL,  347068065ULL,  390451573ULL, 433835081ULL, 477218589ULL,
+	520602097ULL, 563985605ULL,  607369113ULL,  650752621ULL, 694136129ULL, 737519638ULL,
+	780903146ULL, 824286654ULL,  867670162ULL,  911053670ULL, 954437178ULL, 997820686ULL,
+	1041204194ULL, 1084587702ULL, 1127971210ULL, 1171354718ULL, 1214738226ULL, 1258121734ULL,
+	1301505242ULL, 1344888750ULL, 1388272258ULL, 1431655766ULL, 1475039274ULL, 1518422782ULL,
+	1561806290ULL, 1605189798ULL, 1648573306ULL, 1691956814ULL, 1735340322ULL, 1778723830ULL,
+	1822107338ULL, 1865490846ULL, 1908874354ULL, 1952257862ULL, 1995641370ULL, 2039024878ULL,
+	2082408386ULL, 2125791894ULL, 2169175403ULL, 2212558911ULL, 2255942419ULL, 2299325927ULL,
+	2342709435ULL, 2386092943ULL, 2429476451ULL, 2472859959ULL, 2516243467ULL, 2559626975ULL,
+	2603010483ULL, 2646393991ULL, 2689777499ULL, 2733161007ULL, 2776544515ULL, 2819928023ULL,
+	2863311531ULL, 2906695039ULL, 2950078547ULL, 2993462055ULL, 3036845563ULL, 3080229071ULL,
+	3123612579ULL, 3166996087ULL, 3210379595ULL, 3253763103ULL, 3297146611ULL, 3340530119ULL,
+	3383913627ULL, 3427297135ULL, 3470680643ULL, 3514064151ULL, 3557447659ULL, 3600831168ULL,
+	3644214676ULL, 3687598184ULL, 3730981692ULL, 3774365200ULL, 3817748708ULL, 3861132216ULL,
+	3904515724ULL, 3947899232ULL, 3991282740ULL, 4034666248ULL, 4078049756ULL, 4121433264ULL,
+	4164816772ULL, 4208200280ULL, 4251583788ULL, 4294967295ULL};
+
+/**
+ * @brief Test base-2 logarithm function with fixed-point arithmetic
+ *
+ * This test validates the base2_logarithm() function against MATLAB-generated
+ * reference values. It tests 100 uniformly distributed input values across
+ * the full uint32_t range, checking that the fixed-point logarithm calculation
+ * stays within acceptable tolerance.
+ *
+ * Input values: Q32.0 format (unsigned 32-bit integers)
+ * Result: Q16.16 fixed-point format
+ * Reference: MATLAB log2() function results
+ */
+ZTEST(math_advanced_functions_suite, test_math_arithmetic_base2log_fixed)
+{
+	uint32_t u[100];
+	int i, ret;
+
+	BUILD_ASSERT(ARRAY_SIZE(uv) == ARRAY_SIZE(log2_lookup_table),
+		     "Test vector size must match reference table size");
+
+	ret = memcpy_s((void *)&u[0], sizeof(u), (void *)&uv[0], 100U * sizeof(uint32_t));
+	zassert_equal(ret, 0, "memcpy_s failed with error code %d", ret);
+
+	for (i = 0; i < ARRAY_SIZE(u); i++) {
+		float y = Q_CONVERT_QTOF(base2_logarithm(u[i]), 0);
+		float delta = fabsf((float)(log2_lookup_table[i] - (double)y / (1 << 16)));
+
+		zassert_true(delta <= CMP_TOLERANCE,
+			     "base2_logarithm(%u): delta %.16f > tolerance (expected %.16f, got %.16f)",
+			     u[i], (double)delta, log2_lookup_table[i], (double)y / (1 << 16));
+	}
+}

test/ztest/unit/math/advanced/functions/testcase.yaml

@@ -10,7 +10,7 @@
 
 tests:
   sof.unit.math.advanced.functions:
-    tags: math advanced functions power
+    tags: math advanced functions power logarithm base2
     platform_allow: native_sim
     integration_platforms:
       - native_sim