Added some tests

src/test/java/nl/sander/beejava/constantpool/entry/ClassEntryTest.java

@@ -0,0 +1,13 @@
+package nl.sander.beejava.constantpool.entry;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertSame;
+
+public class ClassEntryTest {
+    @Test
+    public void testGetChildren() {
+        Utf8Entry name = new Utf8Entry("");
+        assertSame(new ClassEntry(name).getChildren().iterator().next(), name);
+    }
+}