refactor start script and add option for custom coverage result path

bin/codeclimate-test-reporter

@@ -2,23 +2,20 @@
 
 require "codeclimate-test-reporter"
 
-COVERAGE_FILE = "coverage/.resultset.json".freeze
+repo_token = ENV["CODECLIMATE_REPO_TOKEN"]
+if repo_token.nil? || repo_token.empty?
+  STDERR.puts "Cannot post results: environment variable CODECLIMATE_REPO_TOKEN must be set."
+  exit
+end
+
+COVERAGE_FILE = ARGV.first || "coverage/.resultset.json"
 
-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
+abort "Coverage results not found" unless File.exist?(COVERAGE_FILE)
 
-    CodeClimate::TestReporter.run(results)
-  else
-    $stderr.puts "Coverage results not found"
-    exit(1)
-  end
-else
-  $stderr.puts "Cannot post results: environment variable CODECLIMATE_REPO_TOKEN must be set."
-  exit(0)
+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)