diff --git a/scripts/determine-reboot-cause b/scripts/determine-reboot-cause
index 1e28356491a3..4320b41a7a02 100755
--- a/scripts/determine-reboot-cause
+++ b/scripts/determine-reboot-cause
@@ -158,25 +158,7 @@ def get_reboot_cause_dict(previous_reboot_cause, comment, gen_time):
  
     return reboot_cause_dict
 
-
-def main():
-    # Configure logger to log all messages INFO level and higher
-    sonic_logger.set_min_log_priority_info()
-
-    sonic_logger.log_info("Starting up...")
-
-    if not os.geteuid() == 0:
-        sonic_logger.log_error("User {} does not have permission to execute".format(pwd.getpwuid(os.getuid()).pw_name))
-        sys.exit("This utility must be run as root")
-
-    # Create REBOOT_CAUSE_DIR if it doesn't exist
-    if not os.path.exists(REBOOT_CAUSE_DIR):
-        os.makedirs(REBOOT_CAUSE_DIR)
-
-    # Remove stale PREVIOUS_REBOOT_CAUSE_FILE if it exists
-    if os.path.exists(PREVIOUS_REBOOT_CAUSE_FILE):
-        os.remove(PREVIOUS_REBOOT_CAUSE_FILE)
-
+def determin_reboot_cause():
     # This variable is kept for future-use purpose. When proc_cmd_line/vendor/software provides
     # any additional_reboot_info it will be stored as a "comment" in REBOOT_CAUSE_HISTORY_FILE
     additional_reboot_info = "N/A"
@@ -217,6 +199,29 @@ def main():
         # Get the reboot cause from REBOOT_CAUSE_FILE
         previous_reboot_cause = software_reboot_cause
 
+    return previous_reboot_cause, additional_reboot_info
+
+
+def main():
+    # Configure logger to log all messages INFO level and higher
+    sonic_logger.set_min_log_priority_info()
+
+    sonic_logger.log_info("Starting up...")
+
+    if not os.geteuid() == 0:
+        sonic_logger.log_error("User {} does not have permission to execute".format(pwd.getpwuid(os.getuid()).pw_name))
+        sys.exit("This utility must be run as root")
+
+    # Create REBOOT_CAUSE_DIR if it doesn't exist
+    if not os.path.exists(REBOOT_CAUSE_DIR):
+        os.makedirs(REBOOT_CAUSE_DIR)
+
+    # Remove stale PREVIOUS_REBOOT_CAUSE_FILE if it exists
+    if os.path.exists(PREVIOUS_REBOOT_CAUSE_FILE):
+        os.remove(PREVIOUS_REBOOT_CAUSE_FILE)
+
+    previous_reboot_cause, additional_reboot_info = determin_reboot_cause()
+
     # Current time
     reboot_cause_gen_time = str(datetime.datetime.now().strftime('%Y_%m_%d_%H_%M_%S'))
 
diff --git a/tests/determine-reboot-cause_test.py b/tests/determine-reboot-cause_test.py
index 7d22a512f8ee..743823dc5e26 100644
--- a/tests/determine-reboot-cause_test.py
+++ b/tests/determine-reboot-cause_test.py
@@ -117,3 +117,36 @@ def test_get_reboot_cause_dict_user(self):
     def test_get_reboot_cause_dict_kernel_panic(self):
         reboot_cause_dict = determine_reboot_cause.get_reboot_cause_dict(REBOOT_CAUSE_KERNEL_PANIC, "", GEN_TIME_KERNEL_PANIC)
         assert reboot_cause_dict == EXPECTED_KERNEL_PANIC_REBOOT_CAUSE_DICT
+
+    def test_determine_reboot_cause_hardware(self):
+        with mock.patch("determine_reboot_cause.find_proc_cmdline_reboot_cause", return_value="Unknown"):
+            with mock.patch("determine_reboot_cause.find_software_reboot_cause", return_value="Power Cycle"):
+                with mock.patch("determine_reboot_cause.find_hardware_reboot_cause", return_value="Unknown"):
+                    previous_reboot_cause, additional_info = determine_reboot_cause.determine_reboot_cause()
+                    assert previous_reboot_cause == "Power Cycle"
+                    assert additional_info == "N/A"
+
+    def test_determine_reboot_cause_software(self):
+        with mock.patch("determine_reboot_cause.find_proc_cmdline_reboot_cause", return_value="Unknown"):
+            with mock.patch("determine_reboot_cause.find_software_reboot_cause", return_value="Unknown"):
+                with mock.patch("determine_reboot_cause.find_hardware_reboot_cause", return_value=EXPECTED_FIND_SOFTWARE_REBOOT_CAUSE_USER):
+                    previous_reboot_cause, additional_info = determine_reboot_cause.determine_reboot_cause()
+                    assert previous_reboot_cause == EXPECTED_FIND_SOFTWARE_REBOOT_CAUSE_USER
+                    assert additional_info == "N/A"
+
+    def test_determine_reboot_cause_cmdline(self):
+        with mock.patch("determine_reboot_cause.find_proc_cmdline_reboot_cause", return_value=EXPECTED_PARSE_WARMFAST_REBOOT_FROM_PROC_CMDLINE):
+            with mock.patch("determine_reboot_cause.find_software_reboot_cause", return_value="Unknown"):
+                with mock.patch("determine_reboot_cause.find_hardware_reboot_cause", return_value=EXPECTED_FIND_SOFTWARE_REBOOT_CAUSE_USER):
+                    previous_reboot_cause, additional_info = determine_reboot_cause.determine_reboot_cause()
+                    assert previous_reboot_cause == EXPECTED_FIND_SOFTWARE_REBOOT_CAUSE_USER
+                    assert additional_info == "N/A"
+
+    def test_determine_reboot_cause_cmdline_hardware(self):
+        with mock.patch("determine_reboot_cause.find_proc_cmdline_reboot_cause", return_value=EXPECTED_PARSE_WARMFAST_REBOOT_FROM_PROC_CMDLINE):
+            with mock.patch("determine_reboot_cause.find_software_reboot_cause", return_value=REBOOT_CAUSE_WATCHDOG):
+                with mock.patch("determine_reboot_cause.find_hardware_reboot_cause", return_value=EXPECTED_FIND_SOFTWARE_REBOOT_CAUSE_USER):
+                    previous_reboot_cause, additional_info = determine_reboot_cause.determine_reboot_cause()
+                    assert previous_reboot_cause == REBOOT_CAUSE_WATCHDOG
+                    assert additional_info == EXPECTED_FIND_SOFTWARE_REBOOT_CAUSE_USER
+