Try using shared test util classes

pom.xml

@@ -87,7 +87,19 @@ alternative support for serializing POJOs as XML and deserializing XML as pojos.
     </dependency>
 
     <!-- Test dependencies -->
-
+
+    <!-- 16-Jan-2025, tatu: Use the new (in 3.0) shared core test-jar
+        for some shared test functionality.
+      -->
+    <dependency>
+      <groupId>tools.jackson.core</groupId>
+      <artifactId>jackson-core</artifactId>
+      <version>${jackson.version.core}</version>
+      <classifier>tests</classifier>
+      <type>test-jar</type>
+      <scope>test</scope>
+    </dependency>
+
     <!-- 11-Jan-2025, joohyukkim: For JSTEP-10, migrate to JUnit5 -->
     <dependency>
       <groupId>org.junit.jupiter</groupId>
@@ -100,7 +112,7 @@ alternative support for serializing POJOs as XML and deserializing XML as pojos.
       <scope>test</scope>
     </dependency>
 
-    <!--  Jakarta XMLBind (nee javax/jaxb( annotation introspector is needed BUT ONLY
+    <!--  Jakarta XMLBind (nee javax/jaxb) annotation introspector is needed BUT ONLY
           for tests (starting 2.13: previously compile/runtime)
         -->
     <dependency>

src/test/java/tools/jackson/dataformat/xml/XmlTestUtil.java

@@ -1,19 +1,23 @@
 package tools.jackson.dataformat.xml;
 
 import java.io.*;
-import java.nio.charset.StandardCharsets;
-import java.util.Arrays;
 
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
-import tools.jackson.core.*;
+
+import tools.jackson.core.JsonParser;
+import tools.jackson.core.testutil.JacksonTestUtilBase;
+
 import tools.jackson.databind.AnnotationIntrospector;
+
 import tools.jackson.dataformat.xml.annotation.JacksonXmlProperty;
+
 import tools.jackson.module.jakarta.xmlbind.JakartaXmlBindAnnotationIntrospector;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.fail;
 
 public abstract class XmlTestUtil
+    extends JacksonTestUtilBase
 {
     protected static final String DEFAULT_NEW_LINE;
 
@@ -249,75 +253,19 @@ protected AnnotationIntrospector jakartaXMLBindAnnotationIntrospector() {
     /**********************************************************
      */
 
-    protected void assertToken(JsonToken expToken, JsonToken actToken)
-    {
-        if (actToken != expToken) {
-            fail("Expected token "+expToken+", current token "+actToken);
-        }
-    }
-
-    protected void assertToken(JsonToken expToken, JsonParser jp)
-    {
-        assertToken(expToken, jp.currentToken());
-    }
-
-    /**
-     * Method that gets textual contents of the current token using
-     * available methods, and ensures results are consistent, before
-     * returning them
-     */
-    protected String getAndVerifyText(JsonParser jp)
-        throws IOException
-    {
-        // Ok, let's verify other accessors
-        int actLen = jp.getStringLength();
-        char[] ch = jp.getStringCharacters();
-        String str2 = new String(ch, jp.getStringOffset(), actLen);
-        String str = jp.getString();
-
-        if (str.length() !=  actLen) {
-            fail("Internal problem (jp.token == "+jp.currentToken()+"): jp.getText().length() ['"+str+"'] == "+str.length()+"; jp.getTextLength() == "+actLen);
-        }
-        assertEquals(str, str2, "String access via getText(), getTextXxx() must be the same");
-
-        return str;
-    }
-
     protected void verifyFieldName(JsonParser jp, String expName)
         throws IOException
     {
         assertEquals(expName, jp.getString());
         assertEquals(expName, jp.currentName());
     }
-
-    protected void verifyException(Throwable e, String... matches)
-    {
-        String msg = e.getMessage();
-        String lmsg = (msg == null) ? "" : msg.toLowerCase();
-        for (String match : matches) {
-            String lmatch = match.toLowerCase();
-            if (lmsg.indexOf(lmatch) >= 0) {
-                return;
-            }
-        }
-        fail("Expected an exception with one of substrings ("+Arrays.asList(matches)+"): got one ("+
-                e.getClass().getName()+") with message \""+msg+"\"");
-    }
 
     /*
     /**********************************************************
     /* Helper methods, other
     /**********************************************************
      */
 
-    protected static String a2q(String content) {
-        return content.replace("'", "\"");
-    }
-
-    protected byte[] utf8Bytes(String str) {
-        return str.getBytes(StandardCharsets.UTF_8);
-    }
-
     /**
      * Helper method that tries to remove unnecessary namespace
      * declaration that default JDK XML parser (SJSXP) sees fit
@@ -346,29 +294,6 @@ protected String readAll(File f) throws IOException
         return sb.toString();
     }
 
-    protected byte[] readResource(String ref)
-    {
-       ByteArrayOutputStream bytes = new ByteArrayOutputStream();
-       final byte[] buf = new byte[4000];
-
-       InputStream in = getClass().getResourceAsStream(ref);
-       if (in != null) {
-           try {
-               int len;
-               while ((len = in.read(buf)) > 0) {
-                   bytes.write(buf, 0, len);
-               }
-               in.close();
-           } catch (IOException e) {
-               throw new RuntimeException("Failed to read resource '"+ref+"': "+e);
-           }
-       }
-       if (bytes.size() == 0) {
-           throw new IllegalArgumentException("Failed to read resource '"+ref+"': empty resource?");
-       }
-       return bytes.toByteArray();
-    }
-
     public String jaxbSerialized(Object ob, Class<?>... classes) throws Exception
     {
         StringWriter sw = new StringWriter();