Fix possible IO deadlocks with KorAP tokenizer

Text separators should always have a newline in front of artificial EOTs
to make sure they are recognized and to avoid them being consumed
by regular expressions for tokens.

Change-Id: I528c903904da50312a7472c7a34775476b0955be
diff --git a/t/data/korap_tokenizer_challenge.xml b/t/data/korap_tokenizer_challenge.xml
new file mode 100644
index 0000000..a37c3dc
--- /dev/null
+++ b/t/data/korap_tokenizer_challenge.xml
@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE idsCorpus>
+<idsCorpus version="1.0" TEIform="teiCorpus.2">
+  <idsDoc id="A00" type="text" version="1.0" TEIform="TEI.2">
+    <idsText id="WDD19.H0039.87242" n="de.Diskussion:Hilfswerk_der_Evangelischen_Kirchen_der_Schweiz" version="1">
+      <idsHeader type="text" pattern="text" version="1.0">
+        <fileDesc>
+          <titleStmt>
+            <textSigle>WDD19/H0039.87242</textSigle>
+          </titleStmt>
+        </fileDesc>
+      </idsHeader>
+      <text>
+        <body>
+          <div>
+            <p>?____</p>
+          </div>
+        </body>
+      </text>
+    </idsText>
+  </idsDoc>
+</idsCorpus>
diff --git a/t/script.t b/t/script.t
index fbe28bf..773bb60 100644
--- a/t/script.t
+++ b/t/script.t
@@ -175,6 +175,26 @@
     ->element_count_is('spanList span', 227);
 };
 
+subtest 'Check KorAP tokenizer for infinite loop bug' => sub {
+
+  my $file = catfile($f, 'data', 'korap_tokenizer_challenge.xml');
+
+  eval {
+    require KorAP::XML::TEI::Tokenizer::KorAP;
+    1;
+  } or do {
+    plan skip_all => "KorAP::XML::TEI::Tokenizer::KorAP cannot be used";
+  };
+
+  test_tei2korapxml(
+    file => $file,
+    param => "-tk -s",
+    tmp => 'script_bug_check'
+  )
+    ->stderr_like(qr!tei2korapxml: .*? text_id=WDD19_H0039\.87242!)
+    ->file_readable('WDD19/H0039/87242/struct/structure.xml');
+};
+
 subtest 'Sentence split with KorAP tokenizer' => sub {
 
   eval {