Merge pull request #963 from yancouto/cycle_test

Test for dependency cycle

tests/README.md

+## Creating tests
+
+To create a test, just create a `.rb` file. It should finish normally if the test passed, and end with `exit 1` otherwise, preferably explaining why the test failed.
+
+## Running tests
+
+Just run the `test_all` file. Running tests manually may not work!

tests/no_cycles.rb

+require 'find'
+require_relative '../lib/color'
+
+@all_pkgs = {}
+
+# Loads all packages
+Find.find("#{CUR_DIR}/../packages") do |filename|
+  if File.extname(filename) == '.rb'
+    name = File.basename(filename, '.rb')
+    require_relative("../packages/#{name}")
+    pkg = Object.const_get(name.capitalize)
+    pkg.name = name
+    @all_pkgs[name] = pkg
+  end
+end
+
+# Looking for cycles. @path will keep the current dependency path.
+# @state will store :on_path for vertices on the current dependency path
+# and :visited for vertices that have already been checked not to lead to
+# cycles.
+@state = {}
+@path = []
+def dfs(pkg)
+  @path.push(pkg.name)
+  if @state[pkg] == :on_path
+    puts "Found dependency cycle!".lightred
+    while @path.first != @path.last
+      @path.shift
+    end
+    puts @path.to_s
+    exit 1
+  elsif @state[pkg] == nil
+    @state[pkg] = :on_path
+    if pkg.dependencies
+      pkg.dependencies.each do |name, v|
+        if name != pkg.name
+          dfs(@all_pkgs[name])
+        end
+      end
+    end
+    @state[pkg] = :visited
+  end
+  @path.pop
+end
+
+# Calls dfs for every path
+@all_pkgs.each do |name, pkg|
+  dfs(pkg)
+end
+
+puts "No dependency cycles found.".lightgreen

tests/test_all

+#!/usr/bin/env ruby
+
+require 'find'
+require_relative '../lib/const'
+require_relative '../lib/color'
+
+CUR_DIR = File.dirname(__FILE__)
+
+# Add >LOCAL< lib to LOAD_PATH
+$LOAD_PATH.unshift "#{CUR_DIR}/../lib"
+
+puts "Running tests..."
+
+Find.find(CUR_DIR) do |filename|
+  if File.extname(filename) == '.rb'
+    puts "\nTest Name: #{File.basename(filename, ".rb")}"
+    load filename
+  end
+end
+
+puts "\nAll tests successful.".lightgreen