Add tests on SSML parsing

A corpus of SSML input files will also be needed for fuzzing.
https://github.com/espeak-ng/espeak-ng/issues/407

.gitignore

 !tests/languages.test
 !tests/phoneme-output.test
 !tests/phoneme-audio.test
+!tests/ssml.test
 
 espeak-ng.pc
 

Makefile.am

 	tests/api.check \
 	tests/phoneme-output.check \
 	tests/phoneme-audio.check \
+	tests/ssml.check \
 	tests/languages.check
 
 ##### phoneme data:

tests/ssml.test

+#!/bin/sh
+
+test_ssml() {
+	INPUT=$1
+	echo "testing ${INPUT}"
+	cp $(dirname $INPUT)/$(basename ${INPUT%.*}).expected expected.txt
+	ESPEAK_DATA_PATH=`pwd` LD_LIBRARY_PATH=src:${LD_LIBRARY_PATH} \
+		src/espeak-ng -m -v en-US --ipa=2 -f ${INPUT} > actual.txt
+	diff expected.txt actual.txt || exit 1
+}
+
+for i in `ls tests/ssml/*.ssml` ; do test_ssml $i ; done
+

tests/ssml/billion-laughs.expected

+ lˈɑːl ænd lˈɑːl nˈa͡ɪn
+ lˈɑːl
+

tests/ssml/billion-laughs.ssml

+<?xml version="1.0"?>
+<!-- SSML version of the “Billion laughs” attack
+     https://en.wikipedia.org/wiki/Billion_laughs_attack
+-->
+<!DOCTYPE lolz [
+ <!ENTITY lol "lol">
+ <!ELEMENT lolz (#PCDATA)>
+ <!ENTITY lol1 "&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;">
+ <!ENTITY lol2 "&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;">
+ <!ENTITY lol3 "&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;">
+ <!ENTITY lol4 "&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;">
+ <!ENTITY lol5 "&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;">
+ <!ENTITY lol6 "&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;">
+ <!ENTITY lol7 "&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;">
+ <!ENTITY lol8 "&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;">
+ <!ENTITY lol9 "&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;">
+]>
+<speak version="1.1" xmlns="http://www.w3.org/2001/10/synthesis">
+  lol &lol9; lol
+</speak>

tests/ssml/external-entity.expected

+
+
+ hˈɪɹ ɑː͡ɹ ðə pˈæswɜːdz
+
+
+ ænd ˈɛkszˈiːɾæk
+
+
+

tests/ssml/external-entity.ssml

+<?xml version="1.0"?>
+<!-- SSML version of the “XML External Entity” attack
+     https://en.wikipedia.org/wiki/XML_external_entity_attack
+-->
+<!DOCTYPE test [ 
+    <!ENTITY xxeattack SYSTEM "file:///etc/passwd"> 
+]>
+<speak version="1.1" xmlns="http://www.w3.org/2001/10/synthesis"
+       xml:lang="en-US">
+  <p>Here are the passwords:</p>
+  <p>&xxeattack;</p>
+</speak>

tests/ssml/language-switch.expected

+
+ bˈuːhuː
+
+ bˈoːhuː
+
+ booˈɔo
+
+ bˌooˈoo
+
+

tests/ssml/language-switch.ssml

+<?xml version="1.0"?>
+<speak version="1.1" xmlns="http://www.w3.org/2001/10/synthesis">
+  <p xml:lang="en">Boohoo</p>
+  <p xml:lang="de">Boohoo</p>
+  <p xml:lang="it">Boohoo</p>
+  <p xml:lang="es">Boohoo</p>
+</speak>

tests/ssml/spec-example-1.expected

+
+
+
+ juː hæv fˈoː͡ɹ nˈuː mˈɛsɪd͡ʒᵻz
+
+ ðə fˈɜːst ɪz fɹʌm stˈɛfəni wˈɪljəmz ænd ɚɹˈa͡ɪvd æt
+ θɹˈiː fˈoː͡ɹɾi fˈa͡ɪv pˌiːˈɛm
+
+ ðə sˈʌbd͡ʒɛkt ɪz skˈiː tɹˈɪp
+
+
+

tests/ssml/spec-example-1.ssml

+<?xml version="1.0"?>
+<!-- Example from SSML 1.1 specification, Appendix E
+     https://www.w3.org/TR/speech-synthesis11/#AppE
+-->
+<speak version="1.1"
+       xmlns="http://www.w3.org/2001/10/synthesis"
+       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+       xsi:schemaLocation="http://www.w3.org/2001/10/synthesis
+                   http://www.w3.org/TR/speech-synthesis11/synthesis.xsd"
+       xml:lang="en-US">
+  <p>
+    <s>You have 4 new messages.</s>
+    <s>The first is from Stephanie Williams and arrived at <break/> 3:45pm.</s>
+    <s>
+      The subject is <prosody rate="-20%">ski trip</prosody>
+    </s>
+  </p>
+</speak>