diff --git a/features/cellular/UNITTESTS/at/at_cellulardevice/at_cellulardevicetest.cpp b/features/cellular/UNITTESTS/at/at_cellulardevice/at_cellulardevicetest.cpp
index 1c5165203c..5902ee5524 100644
--- a/features/cellular/UNITTESTS/at/at_cellulardevice/at_cellulardevicetest.cpp
+++ b/features/cellular/UNITTESTS/at/at_cellulardevice/at_cellulardevicetest.cpp
@@ -97,3 +97,17 @@ TEST(AT_CellularDevice, test_AT_CellularDevice_close_information)
     unit->test_AT_CellularDevice_close_information();
 }
 
+TEST(AT_CellularDevice, test_AT_CellularDevice_set_timeout)
+{
+    unit->test_AT_CellularDevice_set_timeout();
+}
+
+TEST(AT_CellularDevice, test_AT_CellularDevice_modem_debug_on)
+{
+    unit->test_AT_CellularDevice_modem_debug_on();
+}
+
+TEST(AT_CellularDevice, test_AT_CellularDevice_get_stack)
+{
+    unit->test_AT_CellularDevice_get_stack();
+}
diff --git a/features/cellular/UNITTESTS/at/at_cellulardevice/test_at_cellulardevice.cpp b/features/cellular/UNITTESTS/at/at_cellulardevice/test_at_cellulardevice.cpp
index 21ccedc61b..8d230164f9 100644
--- a/features/cellular/UNITTESTS/at/at_cellulardevice/test_at_cellulardevice.cpp
+++ b/features/cellular/UNITTESTS/at/at_cellulardevice/test_at_cellulardevice.cpp
@@ -112,22 +112,56 @@ void Test_AT_CellularDevice::test_AT_CellularDevice_open_information()
 
 void Test_AT_CellularDevice::test_AT_CellularDevice_close_network()
 {
+    EventQueue que;
+    AT_CellularDevice dev(que);
+    FileHandle_stub fh1;
+    ATHandler_stub::ref_count = 0;
 
+    CHECK(dev.open_network(&fh1));
+    CHECK(ATHandler_stub::ref_count == 1);
+
+    dev.close_network();
 }
 
 void Test_AT_CellularDevice::test_AT_CellularDevice_close_sms()
 {
+    EventQueue que;
+    AT_CellularDevice dev(que);
+    FileHandle_stub fh1;
+    ATHandler_stub::ref_count = 0;
 
+    CHECK(dev.open_sms(&fh1));
+    CHECK(ATHandler_stub::ref_count == 1);
+
+    dev.close_sms();
 }
 
 void Test_AT_CellularDevice::test_AT_CellularDevice_close_power()
 {
+    EventQueue que;
+    AT_CellularDevice dev(que);
+    FileHandle_stub fh1;
+    ATHandler_stub::ref_count = 0;
 
+    CHECK(dev.open_power(&fh1));
+    CHECK(ATHandler_stub::ref_count == 1);
+
+    dev.close_power();
 }
 
 void Test_AT_CellularDevice::test_AT_CellularDevice_close_sim()
 {
+    EventQueue que;
+    AT_CellularDevice dev(que);
+    FileHandle_stub fh1;
+    ATHandler_stub::ref_count = 0;
 
+
+    CHECK(dev.open_sim(&fh1));
+    dev.close_sms(); // this should not affect to refcount as it's not opened
+    CHECK(ATHandler_stub::ref_count == 1);
+
+    dev.close_sim();
 }
 
 void Test_AT_CellularDevice::test_AT_CellularDevice_close_information()
@@ -155,3 +189,61 @@ void Test_AT_CellularDevice::test_AT_CellularDevice_close_information()
     ATHandler_stub::fh_value = NULL;
 }
 
+void Test_AT_CellularDevice::test_AT_CellularDevice_set_timeout()
+{
+    EventQueue que;
+    AT_CellularDevice dev(que);
+    FileHandle_stub fh1;
+    ATHandler_stub::timeout = 0;
+    ATHandler_stub::default_timeout = false;
+
+    // no interfaces open so settings timeout should not change anything
+    dev.set_timeout(5000);
+    CHECK(ATHandler_stub::timeout == 0);
+    CHECK(ATHandler_stub::default_timeout == false);
+
+    CHECK(dev.open_sim(&fh1));
+    CHECK(ATHandler_stub::ref_count == 1);
+
+    dev.set_timeout(5000);
+    CHECK(ATHandler_stub::timeout == 5000);
+    CHECK(ATHandler_stub::default_timeout == true);
+
+    dev.close_sim();
+}
+
+void Test_AT_CellularDevice::test_AT_CellularDevice_modem_debug_on()
+{
+    EventQueue que;
+    AT_CellularDevice dev(que);
+    FileHandle_stub fh1;
+    ATHandler_stub::debug_on = false;
+
+    // no interfaces open so debug toggling should not affect
+    dev.modem_debug_on(true);
+    CHECK(ATHandler_stub::debug_on == false);
+
+    CHECK(dev.open_sim(&fh1));
+    CHECK(ATHandler_stub::ref_count == 1);
+
+    dev.modem_debug_on(true);
+    CHECK(ATHandler_stub::debug_on == true);
+
+    dev.close_sim();
+}
+
+void Test_AT_CellularDevice::test_AT_CellularDevice_get_stack()
+{
+    EventQueue que;
+    AT_CellularDevice dev(que);
+    FileHandle_stub fh1;
+
+    NetworkStack *stack = dev.get_stack();
+    CHECK(stack == NULL);
+
+    CHECK(dev.open_network(&fh1));
+
+    stack = dev.get_stack();
+    CHECK(stack == NULL); // Not in PPP so also null but this is got from the network class
+}
+
diff --git a/features/cellular/UNITTESTS/at/at_cellulardevice/test_at_cellulardevice.h b/features/cellular/UNITTESTS/at/at_cellulardevice/test_at_cellulardevice.h
index 83873ec4a5..3cf8a8517d 100644
--- a/features/cellular/UNITTESTS/at/at_cellulardevice/test_at_cellulardevice.h
+++ b/features/cellular/UNITTESTS/at/at_cellulardevice/test_at_cellulardevice.h
@@ -47,6 +47,12 @@ public:
     void test_AT_CellularDevice_close_sim();
 
     void test_AT_CellularDevice_close_information();
+
+    void test_AT_CellularDevice_set_timeout();
+
+    void test_AT_CellularDevice_modem_debug_on();
+
+    void test_AT_CellularDevice_get_stack();
 };
 
 #endif // TEST_AT_CELLULARDEVICE_H
diff --git a/features/cellular/UNITTESTS/stubs/ATHandler_stub.cpp b/features/cellular/UNITTESTS/stubs/ATHandler_stub.cpp
index d587395d08..40da5efa2c 100644
--- a/features/cellular/UNITTESTS/stubs/ATHandler_stub.cpp
+++ b/features/cellular/UNITTESTS/stubs/ATHandler_stub.cpp
@@ -31,6 +31,10 @@ const int DEFAULT_AT_TIMEOUT = 1000; // at default timeout in milliseconds
 nsapi_error_t ATHandler_stub::nsapi_error_value = 0;
 uint8_t ATHandler_stub::nsapi_error_ok_counter = 0;
 int ATHandler_stub::int_value = -1;
+int ATHandler_stub::ref_count = 0;
+int ATHandler_stub::timeout = 0;
+bool ATHandler_stub::default_timeout = 0;
+bool ATHandler_stub::debug_on = 0;
 ssize_t ATHandler_stub::ssize_value = 0;
 char* ATHandler_stub::read_string_value = NULL;
 size_t ATHandler_stub::size_value = 0;
@@ -47,27 +51,32 @@ ATHandler::ATHandler(FileHandle *fh, EventQueue &queue, int timeout, const char
     _fileHandle(fh),
     _queue(queue)
 {
+    ATHandler_stub::ref_count = 1;
 }
 
 void ATHandler::enable_debug(bool enable)
 {
+    ATHandler_stub::debug_on = enable;
 }
 
 ATHandler::~ATHandler()
 {
+    ATHandler_stub::ref_count = -909;
 }
 
 void ATHandler::inc_ref_count()
 {
+    ATHandler_stub::ref_count++;
 }
 
 void ATHandler::dec_ref_count()
 {
+    ATHandler_stub::ref_count--;
 }
 
 int ATHandler::get_ref_count()
 {
-    return ATHandler_stub::int_value;
+    return ATHandler_stub::ref_count;
 }
 
 FileHandle *ATHandler::get_file_handle()
@@ -113,6 +122,8 @@ nsapi_error_t ATHandler::unlock_return_error()
 
 void ATHandler::set_at_timeout(uint32_t timeout_milliseconds, bool default_timeout)
 {
+    ATHandler_stub::timeout = timeout_milliseconds;
+    ATHandler_stub::default_timeout = default_timeout;
 }
 
 void ATHandler::restore_at_timeout()
diff --git a/features/cellular/UNITTESTS/stubs/ATHandler_stub.h b/features/cellular/UNITTESTS/stubs/ATHandler_stub.h
index 72fd269583..0aa4be1498 100644
--- a/features/cellular/UNITTESTS/stubs/ATHandler_stub.h
+++ b/features/cellular/UNITTESTS/stubs/ATHandler_stub.h
@@ -28,6 +28,10 @@ namespace ATHandler_stub {
     extern nsapi_error_t nsapi_error_value;
     extern uint8_t nsapi_error_ok_counter;
     extern int int_value;
+    extern int ref_count;
+    extern int timeout;
+    extern bool default_timeout;
+    extern bool debug_on;
     extern ssize_t ssize_value;
     extern char* read_string_value;
     extern size_t size_value;