Improve non-Posix registration of FileTester

Co-authored-by: Copilot <copilot@github.com>

Author: thomas-bc

Svc/FileWorker/CMakeLists.txt

@@ -10,9 +10,6 @@
 #
 ####
 
-if (BUILD_TESTING AND NOT __FPRIME_NO_UT_GEN__)
-    add_fprime_subdirectory("${CMAKE_CURRENT_LIST_DIR}/test/FileTester")
-endif()
 
 register_fprime_module(
   AUTOCODER_INPUTS
@@ -39,18 +36,31 @@ register_fprime_ut(
     "${CMAKE_CURRENT_LIST_DIR}"
 )
 
-register_fprime_ut(
-    FileWorkerTestError
-  AUTOCODER_INPUTS
-    "${CMAKE_CURRENT_LIST_DIR}/FileWorker.fpp"
-  SOURCES
-    "${CMAKE_CURRENT_LIST_DIR}/test/ut/FileWorkerErrTestMain.cpp"
-    "${CMAKE_CURRENT_LIST_DIR}/test/ut/FileWorkerErrTester.cpp"
-  CHOOSES_IMPLEMENTATIONS
-    Svc_FileWorker_test_FileTester
-  DEPENDS
-    STest
-  UT_AUTO_HELPERS
-  WORKING_DIRECTORY
-    "${CMAKE_CURRENT_LIST_DIR}"
-)
+# FileTester is a test dependency and only supported on Posix platforms, therefore:
+# - only attempt to add the FileTester module in BUILD_TESTING
+# - only add the FileWorkerTestError test if the FileTester module was successfully added
+if (BUILD_TESTING AND NOT __FPRIME_NO_UT_GEN__)
+    add_fprime_subdirectory("${CMAKE_CURRENT_LIST_DIR}/test/FileTester")
+
+    # Target will not exist on non-Posix platforms, so guard against its existence
+    if (TARGET Svc_FileWorker_test_FileTester)
+      register_fprime_ut(
+          FileWorkerTestError
+        AUTOCODER_INPUTS
+          "${CMAKE_CURRENT_LIST_DIR}/FileWorker.fpp"
+        SOURCES
+          "${CMAKE_CURRENT_LIST_DIR}/test/ut/FileWorkerErrTestMain.cpp"
+          "${CMAKE_CURRENT_LIST_DIR}/test/ut/FileWorkerErrTester.cpp"
+        CHOOSES_IMPLEMENTATIONS
+          Svc_FileWorker_test_FileTester
+        DEPENDS
+          STest
+        UT_AUTO_HELPERS
+        WORKING_DIRECTORY
+          "${CMAKE_CURRENT_LIST_DIR}"
+      )
+    else()
+      # Only print message if we're in BUILD_TESTING *and* FileTester isn't available
+      message(INFO "Svc/FileWorker: FileTester test dependency is only supported on Posix, skipping FileWorkerTestError")
+    endif()
+endif()