Hide build artifacts.

Author: jgfoster

lib/arduino_ci/cpp_library.rb

@@ -491,7 +491,10 @@ def test_args(aux_libraries, ci_gcc_config)
     # @return [Pathname] path to the compiled test executable
     def build_for_test_with_configuration(test_file, aux_libraries, gcc_binary, ci_gcc_config)
       base = test_file.basename
-      executable = Pathname.new("unittest_#{base}.bin").expand_path
+      # hide build artifacts
+      build_dir = '.arduino_ci'
+      Dir.mkdir build_dir unless File.exists?(build_dir)
+      executable = Pathname.new("#{build_dir}/unittest_#{base}.bin").expand_path
       File.delete(executable) if File.exist?(executable)
       arg_sets = []
       arg_sets << ["-std=c++0x", "-o", executable.to_s, "-DARDUINO=100"]