resolves #71 do not force a default doctype

Author: ggrossetie

lib/options.js

@@ -93,7 +93,6 @@ class Options {
     this.args = {
       'standalone': typeof this.options.standalone !== 'undefined' ? this.options.standalone : true,
       'backend': typeof this.options.backend !== 'undefined' ? this.options.backend : 'html5',
-      'doctype': typeof this.options.doctype !== 'undefined' ? this.options.doctype : 'article',
       'safe-mode': typeof this.options.safe !== 'undefined' ? this.options.safe : 'unsafe'
     }
     if (Array.isArray(this.options.attributes)) {

test/fixtures/doctype.adoc

@@ -0,0 +1,4 @@
+= Title
+:doctype: book
+
+{doctype}

test/test.js

@@ -48,7 +48,7 @@ describe('Options converter', () => {
   it('should have default options', () => {
     const options = defaultOptions.parse('').options
     expect(options['backend']).to.equal('html5')
-    expect(options['doctype']).to.equal('article')
+    expect(options['doctype']).to.be.undefined()
     expect(options['safe']).to.equal('unsafe')
     expect(options['standalone']).to.be.true()
     expect(options['verbose']).to.equal(1)
@@ -317,3 +317,14 @@ describe('Extend', () => {
     expect(opts.options.attributes).to.include('foo=bar')
   })
 })
+
+describe('Convert', () => {
+  it('should convert', () => {
+    const options = new Options().parse(['node', 'asciidoctor', `${__dirname}/fixtures/doctype.adoc`, '-s'])
+    const asciidoctor = require('@asciidoctor/core')()
+    let asciidoctorOptions = options.options
+    Object.assign(asciidoctorOptions, { to_file: false })
+    const result = asciidoctor.convertFile(`${__dirname}/fixtures/doctype.adoc`, asciidoctorOptions)
+    expect(result).to.have.string('<p>book</p>')
+  })
+})