Avoid error when no examples directory exists

Author: ianfixes

Diff for: CHANGELOG.md

@@ -15,6 +15,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 ### Removed
 
 ### Fixed
+- A missing `examples` directory no longer causes a crash in `cpp_library.rb`
 
 ### Security
 

Diff for: lib/arduino_ci/cpp_library.rb

@@ -132,7 +132,10 @@ def info
     # @param installed_library_path [String] The library to query
     # @return [Array<String>] Example sketch files
     def example_sketches
-      reported_dirs = info["library"]["examples"].map(&Pathname::method(:new))
+      examples = info["library"]["examples"]
+      return [] if examples.nil?
+
+      reported_dirs = examples.map(&Pathname::method(:new))
       reported_dirs.map { |e| e + e.basename.sub_ext(".ino") }.select(&:exist?).sort_by(&:to_s)
     end