CMake: Refactor platform unittest CMake

- Add CMake configuration file test suites

platform/tests/UNITTESTS/ATCmdParser/CMakeLists.txt

@@ -0,0 +1,24 @@
+# Copyright (c) 2021 ARM Limited. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+set(TEST_NAME atcmdparser-unittest)
+
+add_executable(${TEST_NAME})
+
+target_sources(${TEST_NAME}
+    PRIVATE
+        ${mbed-os_SOURCE_DIR}/platform/source/ATCmdParser.cpp
+        test_ATCmdParser.cpp
+)
+
+target_link_libraries(${TEST_NAME}
+    PRIVATE
+        mbed-headers
+        mbed-stubs-headers        
+        mbed-stubs-platform      
+        gmock_main
+)
+
+add_test(NAME "${TEST_NAME}" COMMAND ${TEST_NAME})
+
+set_tests_properties(${TEST_NAME} PROPERTIES LABELS "platform")

platform/tests/UNITTESTS/CMakeLists.txt

@@ -0,0 +1,5 @@
+# Copyright (c) 2021 ARM Limited. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+add_subdirectory(ATCmdParser)
+add_subdirectory(CircularBuffer)

platform/tests/UNITTESTS/CircularBuffer/CMakeLists.txt

@@ -0,0 +1,22 @@
+# Copyright (c) 2021 ARM Limited. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+set(TEST_NAME circularbuffer-unittest)
+
+add_executable(${TEST_NAME})
+
+target_sources(${TEST_NAME}
+    PRIVATE        
+        test_CircularBuffer.cpp
+)
+
+target_link_libraries(${TEST_NAME}
+    PRIVATE
+        mbed-headers        
+        mbed-stubs-platform      
+        gmock_main
+)
+
+add_test(NAME "${TEST_NAME}" COMMAND ${TEST_NAME})
+
+set_tests_properties(${TEST_NAME} PROPERTIES LABELS "platform")