lib: sgp4: move tests from module to lib, expose public API

Move NTN tests from `tests/module/` to `tests/lib/` and update
testcase identifiers from `fw` to `lib` prefix.

Move `sat_data_sib32` struct to the header and expose
`parse_sibconfig32_at` and `jd_from_unix_time_ms` as public
functions with proper documentation.

Use `ASSET_TRACKER_TEMPLATE_DIR` variable in CMake files
instead of relative paths.

Signed-off-by: Simen S. Røstad <simen.rostad@nordicsemi.no>

Author: simensrostad

lib/sgp4/Kconfig

@@ -13,6 +13,5 @@ config SGP4_PASS_PREDICT
 	bool "SGP4 satellite pass prediction"
 	default n
 	select SGP4
-	select DATE_TIME
 	help
 	  Enable satellite pass prediction using SGP4 and TLE/SIB32 data.

lib/sgp4/sgp4_pass_predict.c

@@ -4,6 +4,12 @@
  * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
  */
 
+#ifdef _POSIX_C_SOURCE
+#undef _POSIX_C_SOURCE
+#endif
+/* Required for strtok_r() on native_sim / picolibc. */
+#define _POSIX_C_SOURCE 200809L
+
 #include <string.h>
 #include <stdint.h>
 #include <stdlib.h>
@@ -34,26 +40,6 @@ struct datetime {
 	double second;
 };
 
-/* 3GPP TS 36.331 ephemeris parameters format */
-struct sat_data_sib32 {
-	int64_t satelliteId;
-	int64_t epochStar;
-	int64_t meanMotion;
-	int64_t eccentricity;
-	int64_t inclination;
-	int64_t rightAscension;
-	int64_t argumentPerigee;
-	int64_t meanAnomaly;
-	int64_t bStarDecimal;
-	int64_t bStarExponent;
-	int64_t serviceStart;
-	int64_t elevationAngleLeft;
-	int64_t elevationAngleRight;
-	int64_t referencePointLongitude;
-	int64_t referencePointLatitude;
-	int64_t radius;
-};
-
 /* SIBCONFIG 32 AT ephemeris struct field order */
 enum sib_ephemeris_field {
 	FIELD_SATELLITE_ID = 0,
@@ -190,7 +176,7 @@ static uint64_t datetime_to_ts(struct datetime *dt)
 	return days*86400000 + dt->hour*3600000 + dt->minute*60000 + dt->second*1000;
 }
 
-static void jd_from_unix_time_ms(int64_t unix_time_ms, double *jd, double *jdfract)
+void jd_from_unix_time_ms(int64_t unix_time_ms, double *jd, double *jdfract)
 {
 	*jd = (unix_time_ms / 86400000) + 2440587.5;
 	*jdfract = (unix_time_ms % 86400000) / 86400000.0;
@@ -359,7 +345,7 @@ static int parse_ephemeris_struct(char **saveptr, struct sat_data_sib32 *sib32)
 	return 0;
 }
 
-static int parse_sibconfig32_at(const char *atsib32, char *cell_id, struct sat_data_sib32 *sib32)
+int parse_sibconfig32_at(const char *atsib32, char *cell_id, struct sat_data_sib32 *sib32)
 {
 	int err;
 	int sibnr;

lib/sgp4/sgp4_pass_predict.h

@@ -13,6 +13,26 @@
 
 #define MAX_SATELLITES 4
 
+/* 3GPP TS 36.331 ephemeris parameters format */
+struct sat_data_sib32 {
+	int64_t satelliteId;
+	int64_t epochStar;
+	int64_t meanMotion;
+	int64_t eccentricity;
+	int64_t inclination;
+	int64_t rightAscension;
+	int64_t argumentPerigee;
+	int64_t meanAnomaly;
+	int64_t bStarDecimal;
+	int64_t bStarExponent;
+	int64_t serviceStart;
+	int64_t elevationAngleLeft;
+	int64_t elevationAngleRight;
+	int64_t referencePointLongitude;
+	int64_t referencePointLatitude;
+	int64_t radius;
+};
+
 struct next_pass {
 	int64_t start_time_ms;
 	int64_t end_time_ms;
@@ -83,4 +103,24 @@ int sat_data_calculate_next_pass(struct sat_data *sat_data, int sat_index,
  */
 int sat_data_set_name(struct sat_data *sat_data, const char *name);
 
+/**
+ * @brief Parse SIBCONFIG 32 AT command ephemeris parameters
+ *
+ * @param atsib32 The AT SIB32 parameters from modem
+ * @param cell_id Output buffer for cell ID (at least 9 bytes)
+ * @param sib32 Output array for parsed SIB entries, or NULL to only count entries
+ *
+ * @return Number of SIB entries on success, negative error code otherwise
+ */
+int parse_sibconfig32_at(const char *atsib32, char *cell_id, struct sat_data_sib32 *sib32);
+
+/**
+ * @brief Convert Unix time in milliseconds to Julian date
+ *
+ * @param unix_time_ms Unix timestamp in milliseconds
+ * @param jd Whole Julian day
+ * @param jdfract Fractional part of Julian day
+ */
+void jd_from_unix_time_ms(int64_t unix_time_ms, double *jd, double *jdfract);
+
 #endif

tests/module/ntn-sib32/CMakeLists.txt tests/lib/ntn-sib32/CMakeLists.txttests/module/ntn-sib32/CMakeLists.txt renamed to tests/lib/ntn-sib32/CMakeLists.txt

@@ -7,18 +7,20 @@
 cmake_minimum_required(VERSION 3.20.0)
 
 find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
-project(sgp4_pass_test)
+project(ntn_sib32_test)
 
 test_runner_generate(src/test_sib32_tle.c)
 
+set(ASSET_TRACKER_TEMPLATE_DIR ../../..)
+
 target_sources(app
   PRIVATE
   src/test_sib32_tle.c
 )
 
 zephyr_include_directories(${ZEPHYR_BASE}/include/zephyr/)
 zephyr_include_directories(${ZEPHYR_BASE}/subsys/testsuite/include)
-zephyr_include_directories(../../../app/src/common)
-zephyr_include_directories(../../../lib/sgp4)
+zephyr_include_directories(${ASSET_TRACKER_TEMPLATE_DIR}/app/src/common)
+zephyr_include_directories(${ASSET_TRACKER_TEMPLATE_DIR}/lib/sgp4)
 
 target_link_options(app PRIVATE --whole-archive)

tests/module/ntn/prj.conf tests/lib/ntn-sib32/prj.conftests/module/ntn/prj.conf renamed to tests/lib/ntn-sib32/prj.conf

@@ -5,7 +5,6 @@
 #
 
 CONFIG_SGP4_PASS_PREDICT=y
-CONFIG_DATE_TIME_NTP=n
 CONFIG_UNITY=y
 CONFIG_LOG=y
 CONFIG_CBPRINTF_FP_SUPPORT=y

…ts/module/ntn-sib32/src/test_sib32_tle.c tests/lib/ntn-sib32/src/test_sib32_tle.ctests/module/ntn-sib32/src/test_sib32_tle.c renamed to tests/lib/ntn-sib32/src/test_sib32_tle.c tests/module/ntn-sib32/src/test_sib32_tle.c renamed to tests/lib/ntn-sib32/src/test_sib32_tle.c

@@ -17,19 +17,28 @@
 
 /* missing headers */
 struct tm *gmtime_r(const int64_t *timep, struct tm *result);
-char *strtok_r(char *str, const char *delim, char **saveptr);
-
 
 DEFINE_FFF_GLOBALS;
 
+FAKE_VALUE_FUNC(int, date_time_now, int64_t *);
+
+LOG_MODULE_REGISTER(ntn_sib32_test, LOG_LEVEL_DBG);
+
 /* Thu Feb 12 2026 09:38:29 GMT+0000 */
 #define FAKE_TIME_MS 1770889109000LL
-int date_time_now(int64_t *time)
+
+static int date_time_now_custom_fake(int64_t *time)
 {
 	*time = FAKE_TIME_MS;
 	return 0;
 }
 
+void setUp(void)
+{
+	RESET_FAKE(date_time_now);
+	date_time_now_fake.custom_fake = date_time_now_custom_fake;
+}
+
 #define LAT_TRD 63.43
 #define LON_TRD 10.39
 #define ALT_TRD 40.0

tests/module/ntn-sib32/testcase.yaml tests/lib/ntn-sib32/testcase.yamltests/module/ntn-sib32/testcase.yaml renamed to tests/lib/ntn-sib32/testcase.yaml

@@ -1,5 +1,5 @@
 tests:
-  asset_tracker_template.fw.ntn-sib32:
+  asset_tracker_template.lib.ntn-sib32:
     platform_allow:
       - native_sim
       - native_sim/native/64

tests/module/ntn/CMakeLists.txt tests/lib/ntn/CMakeLists.txttests/module/ntn/CMakeLists.txt renamed to tests/lib/ntn/CMakeLists.txt

@@ -7,18 +7,20 @@
 cmake_minimum_required(VERSION 3.20.0)
 
 find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
-project(sgp4_pass_test)
+project(ntn_sgp4_test)
 
 test_runner_generate(src/sgp4_pass_test.c)
 
+set(ASSET_TRACKER_TEMPLATE_DIR ../../..)
+
 target_sources(app
   PRIVATE
   src/sgp4_pass_test.c
 )
 
 zephyr_include_directories(${ZEPHYR_BASE}/include/zephyr/)
 zephyr_include_directories(${ZEPHYR_BASE}/subsys/testsuite/include)
-zephyr_include_directories(../../../app/src/common)
-zephyr_include_directories(../../../lib/sgp4)
+zephyr_include_directories(${ASSET_TRACKER_TEMPLATE_DIR}/app/src/common)
+zephyr_include_directories(${ASSET_TRACKER_TEMPLATE_DIR}/lib/sgp4)
 
 target_link_options(app PRIVATE --whole-archive)

tests/module/ntn-sib32/prj.conf tests/lib/ntn/prj.conftests/module/ntn-sib32/prj.conf renamed to tests/lib/ntn/prj.conf

@@ -5,7 +5,6 @@
 #
 
 CONFIG_SGP4_PASS_PREDICT=y
-CONFIG_DATE_TIME_NTP=n
 CONFIG_UNITY=y
 CONFIG_LOG=y
 CONFIG_CBPRINTF_FP_SUPPORT=y

tests/module/ntn/src/sgp4_pass_test.c tests/lib/ntn/src/sgp4_pass_test.ctests/module/ntn/src/sgp4_pass_test.c renamed to tests/lib/ntn/src/sgp4_pass_test.c

@@ -17,21 +17,30 @@
 
 /* missing headers */
 struct tm *gmtime_r(const int64_t *timep, struct tm *result);
-char *strtok_r(char *str, const char *delim, char **saveptr);
-
 
 DEFINE_FFF_GLOBALS;
 
+FAKE_VALUE_FUNC(int, date_time_now, int64_t *);
+
+LOG_MODULE_REGISTER(ntn_sgp4_test, LOG_LEVEL_DBG);
+
 static struct sat_data sat_data_tle;
 
 /* Mon Mar 02 2026 08:50:24 */
 #define FAKE_TIME_MS 1772441424123LL
-int date_time_now(int64_t *time)
+
+static int date_time_now_custom_fake(int64_t *time)
 {
 	*time = FAKE_TIME_MS;
 	return 0;
 }
 
+void setUp(void)
+{
+	RESET_FAKE(date_time_now);
+	date_time_now_fake.custom_fake = date_time_now_custom_fake;
+}
+
 static void debug_print_next_pass(struct sat_data *data)
 {
 	struct tm start_tm, end_tm, max_elevation_tm;