gentest for Java and C#

Summary:
- Revise scripts to generate Java and C# unittests using the same HTML fixtures as well as C for code coverage.
- Add wrap_column test workaround in gentest.js.
- Add checkDefaultValues for sanity check of the CSSLayout default values by test-template.html
- Add `align-content: flex-start;` in default div to align with CSSLayout default

    $ cd csharp/gentest
    $ ruby gentest.rb

- macOS example for C#

    $ cd csharp/tests/Facebook.CSSLayout
    $ clang -DCSS_ASSERT_FAIL_ENABLED -Wall -Wextra -dynamiclib -o libCSSLayout.dylib -g -I../../.. ../../../CSSLayout/*.c ../../CSSLayout/CSSInterop.cpp
    $ mcs -debug -t:library -r:nunit.framework.dll -out:CSSLayoutTest.dll *.cs ../../../csharp/Facebook.CSSLayout/*cs
    $ mono64 --debug nunit-console.exe CSSLayoutTest.dll

Reviewed By: emilsjolander

Differential Revision: D4053777

fbshipit-source-id: 84450208015e65baf604987bd56c6a268598b545

gentest/gentest.rb

@@ -0,0 +1,44 @@
+#!/usr/bin/env ruby
+require 'watir-webdriver'
+require 'fileutils'
+caps = Selenium::WebDriver::Remote::Capabilities.chrome(
+  "loggingPrefs"=>{"browser"=>"ALL", "performance"=>"ALL"})
+browser = Watir::Browser.new(:chrome, :desired_capabilities => caps)
+Dir['fixtures/*.html'].each do |file|
+  fixture = File.read(file)
+  name = File.basename(file, '.*')
+  puts "Generate #{name}"
+
+  ltr_fixture = fixture.gsub('start', 'left')
+                       .gsub('end', 'right')
+                       .gsub('flex-left', 'flex-start')
+                       .gsub('flex-right', 'flex-end')
+
+  rtl_fixture = fixture.gsub('start', 'right')
+                       .gsub('end', 'left')
+                       .gsub('flex-right', 'flex-start')
+                       .gsub('flex-left', 'flex-end')
+
+  template = File.open('test-template.html').read
+  f = File.open('test.html', 'w')
+  f.write sprintf(template, ltr_fixture, rtl_fixture, fixture)
+  f.close
+  FileUtils.copy('test.html', "#{name}.html") if $DEBUG
+
+  browser.goto('file://' + Dir.pwd + '/test.html')
+  logs = browser.driver.manage.logs.get(:browser)
+
+  f = File.open("../tests/#{name}.cpp", 'w')
+  f.write eval(logs[0].message.sub(/^[^"]*/, ''))
+  f.close
+
+  f = File.open("../java/tests/com/facebook/csslayout/#{name}.java", 'w')
+  f.write eval(logs[1].message.sub(/^[^"]*/, '')).sub('CSSNodeLayoutTest', name)
+  f.close
+
+  f = File.open("../csharp/tests/Facebook.CSSLayout/#{name}.cs", 'w')
+  f.write eval(logs[2].message.sub(/^[^"]*/, '')).sub('CSSNodeLayoutTest', name)
+  f.close
+end
+File.delete('test.html')
+browser.close