Doesn't detect/render additions to the API

Try this....

See last exploratory test I added to the existing test case.
As a user it just seems totally broken?

package org.openapitools.openapidiff.core;

import io.swagger.parser.OpenAPIParser;
import io.swagger.v3.oas.models.OpenAPI;
import io.swagger.v3.oas.models.Operation;
import io.swagger.v3.oas.models.PathItem;
import io.swagger.v3.oas.models.tags.Tag;
import io.swagger.v3.parser.core.models.SwaggerParseResult;
import org.junit.jupiter.api.Test;
import org.openapitools.openapidiff.core.model.Changed;
import org.openapitools.openapidiff.core.model.ChangedOpenApi;
import org.openapitools.openapidiff.core.output.ConsoleRender;

import static org.assertj.core.api.Assertions.assertThat;
import static org.junit.jupiter.api.Assertions.assertThrows;
import static org.openapitools.openapidiff.core.TestUtils.assertOpenApiAreEquals;
import static org.openapitools.openapidiff.core.model.DiffResult.COMPATIBLE;

public class PathDiffTest {

    private final String OPENAPI_PATH1 = "path_1.yaml";
    private final String OPENAPI_PATH2 = "path_2.yaml";
    private final String OPENAPI_PATH3 = "path_3.yaml";
    private final String OPENAPI_PATH4 = "path_4.yaml";

    @Test
    public void testEqual() {
        assertOpenApiAreEquals(OPENAPI_PATH1, OPENAPI_PATH2);
    }

    @Test
    public void testMultiplePathWithSameSignature() {
        assertThrows(
                IllegalArgumentException.class, () -> assertOpenApiAreEquals(OPENAPI_PATH3, OPENAPI_PATH3));
    }

    @Test
    public void testSameTemplateDifferentMethods() {
        ChangedOpenApi changedOpenApi = OpenApiCompare.fromLocations(OPENAPI_PATH1, OPENAPI_PATH4);
        assertThat(changedOpenApi.getNewEndpoints())
                .hasSize(1)
                .satisfiesExactly(endpoint -> assertThat(endpoint.getOperation().getOperationId()).isEqualTo("deletePet"));
        assertThat(changedOpenApi.isCompatible()).isTrue();
    }

    @Test
    void exploratoryTest() {

        // clean original spec
        OpenAPIParser parser = new OpenAPIParser();
        SwaggerParseResult origDoc = parser.readLocation(OPENAPI_PATH1, null, null);
        OpenAPI origOpenAPI = origDoc.getOpenAPI();

        // hacked copy of the same original
        SwaggerParseResult newDoc = parser.readLocation(OPENAPI_PATH1, null, null);
        OpenAPI newOpenAPI = newDoc.getOpenAPI();

        Tag tag = new Tag();
        tag.setDescription("ADDED TAG");
        tag.setName("ADDED TAGNAME");

        newOpenAPI.addTagsItem(tag);
        PathItem addedPathItem = new PathItem();
        addedPathItem.setDescription("ADDED PATH");
        Operation op = new Operation();
        op.setOperationId("ADDEDOPID");
        addedPathItem.setGet(op);
        newOpenAPI.getPaths().addPathItem("ADDEDPATH", addedPathItem);

        // now compare them
        ChangedOpenApi changedOpenApi = OpenApiCompare.fromSpecifications(origOpenAPI, newOpenAPI);
        assertThat(changedOpenApi.isChanged()).isEqualTo(COMPATIBLE); // ok so it knows something has changed??
        assertThat(changedOpenApi.isDifferent()).isEqualTo(true); // yep something has changed


        // but the reporting doesn't tell me what
        assertThat(changedOpenApi.getChangedElements()).hasSizeGreaterThan(0);
        System.out.println("---");
        System.out.println("CHANGES SIZE : " + changedOpenApi.getChangedElements().size());
        System.out.println("---");
        System.out.println("??!! THIS COMES BACK A [null] ie a null element !!: " + changedOpenApi.getChangedElements());
        System.out.println("---");
        System.out.println("diffs should surely render the additional elements that I added??  - but it does nothing??");
        ConsoleRender cr = new ConsoleRender();
        cr.render(changedOpenApi);
        System.out.println("!! some diff should have been printed above ");

        //assertThat(changedOpenApi.getMissingEndpoints()).hasSize(1);
        ///assertThat(changedOpenApi.isCompatible()).isTrue();

    }
}

Beginne mit dem exploratoryTest in PathDiffTest und verfolge OpenApiCompare.fromSpecifications bis zu ConsoleRender.render. Führe den Test aus, um changedElements und die Konsolenausgabe für das hinzugefügte Tag, den Pfad und die Operation zu prüfen; als erledigt gilt die Aufgabe, wenn diese Ergänzungen dargestellt und gerendert werden, anstatt ein null-Element oder keinen Diff zu erzeugen.