Fixes crash when html has an xml version tag by stripping it out

lib/readability.ex

@@ -55,6 +55,7 @@ defmodule Readability do
             div_to_p_elements: ~r/<(a|blockquote|dl|div|img|ol|p|pre|table|ul)/i,
             replace_brs: ~r/(<br[^>]*>[ \n\r\t]*){2,}/i,
             replace_fonts: ~r/<(\/?)font[^>]*>/i,
+            replace_xml_version: ~r/<\?xml.*\?>/i,
             normalize: ~r/\s{2,}/,
             video: ~r/\/\/(www\.)?(dailymotion|youtube|youtube-nocookie|player\.vimeo)\.com/i,
             protect_attrs: ~r/^(?!id|rel|for|summary|title|href|src|alt|srcdoc)/i

lib/readability/helper.ex

@@ -92,6 +92,7 @@ defmodule Readability.Helper do
   @spec normalize(binary) :: html_tree
   def normalize(raw_html) do
     raw_html
+    |> String.replace(Readability.regexes[:replace_xml_version], "")
     |> String.replace(Readability.regexes[:replace_brs], "</p><p>")
     |> String.replace(Readability.regexes[:replace_fonts], "<\1span>")
     |> String.replace(Readability.regexes[:normalize], " ")

test/readability_test.exs

@@ -59,4 +59,19 @@ defmodule ReadabilityTest do
     assert buzzfeed_text =~ ~r/^The FBI no longer needs Apple’s help/
     assert buzzfeed_text =~ ~r/issue of court orders and encrypted devices.$/
   end
+
+  test "readability for pubmed" do
+    html = TestHelper.read_fixture("pubmed.html")
+    pubmed = Readability.article(html)
+
+    pubmed_html = Readability.readable_html(pubmed)
+
+    assert pubmed_html =~ ~r/^<div><div><h4>BACKGROUND AND OBJECTIVES: <\/h4><p><abstracttext>Although strict blood pressure/
+    assert pubmed_html =~ ~r/different mechanisms yielded potent antihypertensive efficacy with safety and decreased plasma BNP levels.<\/abstracttext><\/p><\/div><\/div>$/
+
+    pubmed_text = Readability.readable_text(pubmed)
+
+    assert pubmed_text =~ ~r/^BACKGROUND AND OBJECTIVES: \nAlthough strict blood pressure/
+    assert pubmed_text =~ ~r/with different mechanisms yielded potent antihypertensive efficacy with safety and decreased plasma BNP levels.$/
+  end
 end