avoid problems related to finding a symbolic link

Author: ianfixes

lib/arduino_ci/cpp_library.rb

@@ -27,12 +27,13 @@ def initialize(base_dir)
     end
 
     def cpp_files_in(some_dir)
-      Find.find(some_dir).select { |path| CPP_EXTENSIONS.include?(File.extname(path)) }
+      real = File.realpath(some_dir)
+      Find.find(real).select { |path| CPP_EXTENSIONS.include?(File.extname(path)) }
     end
 
     # CPP files that are part of the project library under test
     def cpp_files
-      cpp_files_in(@base_dir).reject { |p| p.start_with?(tests_dir + File::SEPARATOR) }
+      cpp_files_in(@base_dir).reject { |p| File.dirname(p).include?(tests_dir) }
     end
 
     # CPP files that are part of the arduino mock library we're providing