void shouldHandleMergingWithDifferentPOMSets() {
            Path pom1 = Paths.get("pom.xml");
            Path pom2 = Paths.get("module1/pom.xml");
            Path pom3 = Paths.get("module2/pom.xml");

            UpgradeResult result1 = new UpgradeResult(
                    Set.of(pom1, pom2), // processed
                    Set.of(pom1), // modified
                    Set.of() // errors
                    );

            context.indent();
            context.info("Processed: " + result.processedPoms().size() + " POMs");
            context.info("Modified: " + result.modifiedPoms().size() + " POMs");
            context.failure("Errors: " + result.errorPoms().size() + " POMs");
            context.unindent();
        } else if (!result.modifiedPoms().isEmpty()) {

/**
 * Result of an upgrade strategy application.
 * Uses sets of paths to track which POMs were processed, modified, or had errors,
 * avoiding double-counting when multiple strategies affect the same POMs.
 *
 * @param processedPoms the set of POMs that were processed
 * @param modifiedPoms the set of POMs that were modified
 * @param errorPoms the set of POMs that had errors
 */

    /**
     * Check most classical urls inheritance: directory structure where parent POM in parent directory
     * and child directory == artifactId
     * @throws IOException Model read problem
     */
    @Test
    void testUrls() throws Exception {
        testInheritance("urls");
    }

    /**
     * Flat directory structure: parent & child POMs in sibling directories, child directory == artifactId.

      <![CDATA[
      This is a list of ArtifactRepository instances used to resolve the Artifacts associated
      with the current POM.

      NOTE: This list will contain entries for repositories specified by ancestor POMs, including
      the default built-in super-POM, which is the parent of all POMs.
    ]]></description>
  </expression>
  <expression>
    <syntax>project.pluginArtifactRepositories</syntax>
    <configuration>

        results.add(result2);

        ProjectBuildingException exception = new ProjectBuildingException(results);
        String message = exception.getMessage();

        assertTrue(
                message.contains("3 problems were encountered while processing the POMs (2 errors)"),
                "Message should contain problem count and error count");

        int i = 0;
        for (Path pom : state.poms) {
            try (InputStream is = Files.newInputStream(pom)) {
                MavenStaxReader reader = new MavenStaxReader();
                reader.setAddLocationInformation(false);
                reader.read(is, true, InputSource.of("id", pom.toString()));
                i++;
            } catch (XMLStreamException e) {

        return new Parser().parse(content);
    }

    /**
     * Recursively discovers module POMs from the given parent POM.
     *
     * @param baseDirectory the base directory for resolving module paths
     * @param parentPom the parent POM document
     * @param pomMap the map to store discovered POMs
     * @throws IOException if there's an error reading files
     * @throws DomTripException if there's an error parsing XML

 * are validated to ensure they don't contain duplicates or null entries.
 *
 * <p>Remote repositories are used for:
 * <ul>
 *   <li>Resolving artifacts and their metadata</li>
 *   <li>Downloading parent POMs and dependency POMs</li>
 *   <li>Retrieving version information and ranges</li>
 *   <li>Accessing plugin artifacts and their dependencies</li>
 * </ul>
 *
 * <p>Repository validation ensures data integrity by:
 * <ul>

/**
 * Represents a source for loading Maven Project Object Model (POM) files. This interface
 * extends the basic {@link Source} interface with specific functionality for handling
 * Maven POM files and resolving related project POMs.
 *
 * <p>The interface provides two types of sources:</p>
 * <ul>
 *   <li>Build sources: Used for POM files of projects being built by Maven in the filesystem.