Add unit tests for parsing consensuses.

The parser doesn't detect many problems yet.  Most of the unit tests check
for the absence of exceptions when they really should test for the
exceptions.  This is more like a TODO list for making the parser better.

build.xml

@@ -1,10 +1,12 @@
 <project default="run" name="descriptor" basedir=".">
   <property name="sources" value="src"/>
   <property name="classes" value="classes"/>
+  <property name="tests" value="test"/>
   <property name="libs" value="lib"/>
   <path id="classpath">
     <pathelement path="${classes}"/>
     <pathelement location="lib/commons-codec-1.4.jar"/>
+    <pathelement location="lib/junit-4.8.2.jar"/>
   </path>
   <target name="init">
     <mkdir dir="${classes}"/>
@@ -29,5 +31,28 @@
     <jar destfile="descriptor.jar"
          basedir="${classes}"/>
   </target>
+  <target name="test" depends="compile">
+    <javac destdir="${classes}"
+           srcdir="${tests}"
+           source="1.5"
+           target="1.5"
+           debug="true"
+           deprecation="true"
+           optimize="false"
+           failonerror="true"
+           includeantruntime="false">
+      <classpath>
+        <fileset dir="${libs}"/>
+      </classpath>
+    </javac>
+    <junit haltonfailure="true" printsummary="off">
+      <classpath refid="classpath"/>
+      <formatter type="plain" usefile="false"/>
+      <batchtest>
+        <fileset dir="${classes}"
+                 includes="**/*Test.class"/>
+      </batchtest>
+    </junit>
+  </target>
 </project>