Raise proper FileNotFound errors (#128)

lib/expressir/express/parser.rb

@@ -31,11 +31,12 @@ class Parser
  # @param [Boolean] include_source attach original source code to model elements
  # @return [Model::Repository]
  def self.from_file(file, skip_references: nil, include_source: nil)
+ raise Errno::ENOENT, "File not found: #{file}" unless File.exist?(file)
 
  # An important note re memory management
  # parse, syntax, visitor methods return complex tree structures created in native (C++) extension
  # visit method references nodes and leaves of this structures but it is totally untransparent for Ruby GarbageCllector
- # so in this class we keep those C++ structure marked for GC so they are not freed 
+ # so in this class we keep those C++ structure marked for GC so they are not freed
  @parser = ::ExpressParser::ParserExt.new(file.to_s)
  @parse_tree = @parser.syntax()
 

spec/expressir/express/cache_spec.rb

@@ -33,6 +33,13 @@
  end
 
  describe ".from_file" do
+ it "throws an exception if the cache file does not exist" do |example|
+ print "\n[#{example.description}] "
+ expect do
+ Expressir::Express::Cache.from_file("non-existing-file", test_overwrite_version: TEST_VERSION)
+ end.to raise_error(Errno::ENOENT)
+ end
+
  it "parses a file" do |example|
  print "\n[#{example.description}] "
  temp_file = Tempfile.new

spec/expressir/express/parser_spec.rb

@@ -4,6 +4,13 @@
 
 RSpec.describe Expressir::Express::Parser do
  describe ".from_file" do
+ it "throws an exception if the file to parse does not exist" do |example|
+ print "\n[#{example.description}] "
+ expect do
+ Expressir::Express::Parser.from_file("non-existing-file")
+ end.to raise_error(Errno::ENOENT)
+ end
+
  it "parses a file (single.exp)" do |example|
  print "\n[#{example.description}] "
  exp_file = Expressir.root_path.join("spec", "syntax", "single.exp")