refactor start script and add option for custom coverage directory

bin/codeclimate-test-reporter

@@ -1,24 +1,35 @@
 #!/usr/bin/env ruby
 
 require "codeclimate-test-reporter"
+require "optparse"
 
-COVERAGE_FILE = "coverage/.resultset.json".freeze
-
-if (repo_token = ENV["CODECLIMATE_REPO_TOKEN"]) && !repo_token.empty?
-  if File.exist?(COVERAGE_FILE)
-    begin
-      results = JSON.parse(File.read(COVERAGE_FILE))
-    rescue JSON::ParserError => e
-      $stderr.puts "Error encountered while parsing #{COVERAGE_FILE}: #{e}"
-      exit(1)
-    end
-
-    CodeClimate::TestReporter.run(results)
-  else
-    $stderr.puts "Coverage results not found"
-    exit(1)
+repo_token = ENV["CODECLIMATE_REPO_TOKEN"]
+if repo_token.nil? || repo_token.empty?
+  abort "Cannot post results: environment variable CODECLIMATE_REPO_TOKEN must be set."
+end
+
+coverage_dir = "coverage"
+parser = OptionParser.new do |p|
+  p.banner = "Usage: #{$0} [options]"
+  on("-d PATH", "--directory PATH", "Path to coverage results directory (default: coverage)") do |path|
+    coverage_dir = path
+  end
+
+  p.on("-h", "--help", "Show this message") do
+    puts p
+    exit
   end
-else
-  $stderr.puts "Cannot post results: environment variable CODECLIMATE_REPO_TOKEN must be set."
-  exit(0)
 end
+
+parser.parse!
+
+coverage_file = File.join(coverage_dir, ".resultset.json")
+abort "Coverage results not found" unless File.exist?(coverage_file)
+
+begin
+  results = JSON.parse(File.read(coverage_file))
+rescue JSON::ParserError => e
+  abort("Error encountered while parsing #{coverage_file}: #{e}")
+end
+
+CodeClimate::TestReporter.run(results)