Add entity resolver test

Author: physikerwelt

src/test/java/com/formulasearchengine/mathmltools/xmlhelper/PartialLocalEntityResolverTest.java

@@ -0,0 +1,18 @@
+package com.formulasearchengine.mathmltools.xmlhelper;
+
+        import org.junit.Assert;
+        import org.junit.Test;
+
+/**
+ * Created by Moritz on 18.03.2017.
+ */
+public class PartialLocalEntityResolverTest {
+    @Test
+    public void resolveEntity() throws Exception {
+
+        final PartialLocalEntityResolver resolver = new PartialLocalEntityResolver();
+        Assert.assertNull(resolver.resolveEntity("a", "b"));
+        Assert.assertNotNull(resolver.resolveEntity("a", "http://www.w3.org/Math/DTD/mathml2/xhtml-math11-f.dtd"));
+    }
+
+}