Тестовое поведение, а не реализация

package com.mkovacek.aem.core.servlets.products;

import com.mkovacek.aem.core.models.products.ProductDetailsModel;
import com.mkovacek.aem.core.records.response.Response;
import com.mkovacek.aem.core.services.products.ProductDetailsService;
import com.mkovacek.aem.core.services.response.ResponseService;

import lombok.extern.slf4j.Slf4j;

import org.apache.commons.lang3.StringUtils;
import org.apache.sling.api.SlingHttpServletRequest;
import org.apache.sling.api.SlingHttpServletResponse;
import org.apache.sling.api.resource.Resource;
import org.apache.sling.api.servlets.HttpConstants;
import org.apache.sling.api.servlets.SlingSafeMethodsServlet;
import org.apache.sling.servlets.annotations.SlingServletResourceTypes;
import org.osgi.service.component.annotations.Component;
import org.osgi.service.component.annotations.Reference;

import javax.servlet.Servlet;
import javax.servlet.ServletException;

import java.io.IOException;

@Slf4j
@Component(service = Servlet.class)
@SlingServletResourceTypes(
    resourceTypes = ProductDetailsServlet.RESOURCE_TYPE,
    selectors = ProductDetailsServlet.ALLOWED_SELECTOR,
    extensions = ProductDetailsServlet.JSON,
    methods = HttpConstants.METHOD_GET)
public class ProductDetailsServlet extends SlingSafeMethodsServlet {

    public static final String ALLOWED_SELECTOR = "productdetails";
    static final String RESOURCE_TYPE = "demo/components/productdetails";
    static final String JSON = "json";

    @Reference
    private transient ResponseService responseService;

    @Reference
    private transient ProductDetailsService productDetailsService;

    @Override
    public void doGet(final SlingHttpServletRequest request, final SlingHttpServletResponse response) throws ServletException, IOException {
        try {
            this.responseService.setJsonContentType(response);
            final String selector = request.getRequestPathInfo().getSelectorString();
            final String productId = this.responseService.getSuffix(request);

            if (this.responseService.areSelectorsValid(selector, ALLOWED_SELECTOR) && StringUtils.isNotBlank(productId)) {
                final Resource resource = request.getResource();
                final Response data = this.productDetailsService.getProductDetails(productId, resource);
                this.responseService.sendOk(response, data);
            } else {
                this.responseService.sendBadRequest(response);
            }
        } catch (final Exception e) {
            log.error("Exception during handling request", e);
            this.responseService.sendInternalServerError(response);
        }
    }

}

package com.mkovacek.aem.core.services.products.impl;

import com.day.cq.wcm.api.PageManager;
import com.mkovacek.aem.core.models.products.ProductDetailsModel;
import com.mkovacek.aem.core.records.response.Response;
import com.mkovacek.aem.core.records.response.Status;
import com.mkovacek.aem.core.services.products.ProductDetailsService;
import com.mkovacek.aem.core.services.resourceresolver.ResourceResolverService;

import lombok.extern.slf4j.Slf4j;

import org.apache.commons.lang3.StringUtils;
import org.apache.sling.api.resource.Resource;
import org.apache.sling.api.resource.ResourceResolver;
import org.osgi.service.component.annotations.Component;
import org.osgi.service.component.annotations.Reference;

import java.util.Locale;
import java.util.Optional;

@Slf4j
@Component(service = ProductDetailsService.class, immediate = true)
public class ProductDetailsServiceImpl implements ProductDetailsService {

    private static final String PIM_READER = "pimReader";
    private static final Response notFoundResponse = new Response<>(new Status(true, "Product Details not found"), null);
    private static final Response errorResponse = new Response<>(new Status(false, "Error during fetching product details"), null);

    @Reference
    private ResourceResolverService resourceResolverService;

    @Override
    public Response getProductDetails(final String id, final Resource resource) {
        try (final ResourceResolver resourceResolver = this.resourceResolverService.getResourceResolver(PIM_READER)) {
            final Locale locale = resourceResolver.adaptTo(PageManager.class).getContainingPage(resource).getLanguage(false);
            //usually this would be implemented with query
            final String productPath = StringUtils.join("/var/commerce/products/demo/", id);
            return Optional.ofNullable(resourceResolver.getResource(productPath))
                       .map(productResource -> productResource.adaptTo(ProductDetailsModel.class))
                       .map(productDetailsModel -> productDetailsModel.setLocale(locale))
                       .filter(ProductDetailsModel::isValid)
                       .map(productDetailsModel -> new Response<>(new Status(true), productDetailsModel))
                       .orElse(notFoundResponse);
        } catch (final Exception e) {
            log.error("Exception during fetching product details", e);
        }
        return errorResponse;
    }

}

package com.mkovacek.aem.core.models.products;

import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.mkovacek.aem.core.services.products.ProductLocalizationService;
import com.mkovacek.aem.core.services.products.ProductValidatorService;

import lombok.Getter;
import lombok.extern.slf4j.Slf4j;

import org.apache.commons.lang3.StringUtils;
import org.apache.sling.api.resource.Resource;
import org.apache.sling.api.resource.ValueMap;
import org.apache.sling.models.annotations.Default;
import org.apache.sling.models.annotations.DefaultInjectionStrategy;
import org.apache.sling.models.annotations.Model;
import org.apache.sling.models.annotations.injectorspecific.ChildResource;
import org.apache.sling.models.annotations.injectorspecific.OSGiService;
import org.apache.sling.models.annotations.injectorspecific.Self;
import org.apache.sling.models.annotations.injectorspecific.ValueMapValue;

import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;
import java.util.Locale;

@Slf4j
@Model(adaptables = {Resource.class}, defaultInjectionStrategy = DefaultInjectionStrategy.OPTIONAL)
public class ProductDetailsModel {

    @ValueMapValue
    @Default(values = StringUtils.EMPTY)
    @Getter
    private String id;

    @ValueMapValue
    @Default(values = StringUtils.EMPTY)
    @Getter
    private String categoryId;

    @ChildResource
    @Getter
    private List images;

    @ChildResource
    private List variants;

    @Self
    private ValueMap valueMap;

    @OSGiService
    private ProductLocalizationService productLocalizationService;

    @OSGiService
    private ProductValidatorService productValidatorService;

    @Getter
    @JsonProperty("variants")
    private List validVariants = new ArrayList<>();

    @Getter
    private String name = StringUtils.EMPTY;

    @Getter
    private String description = StringUtils.EMPTY;

    @JsonIgnore
    public boolean isValid() {
        return !this.validVariants.isEmpty();
    }

    @JsonIgnore
    public ProductDetailsModel setLocale(final Locale locale) {
        this.setLocalizedValues(locale);
        this.validateAndSortVariants(locale);
        return this;
    }

    private void setLocalizedValues(final Locale locale) {
        this.name = this.productLocalizationService.getLocalizedProductDetail(this.valueMap, "name.", locale);
        this.description = this.productLocalizationService.getLocalizedProductDetail(this.valueMap, "description.", locale);
    }

    private void validateAndSortVariants(final Locale locale) {
        this.validVariants = this.productValidatorService.getValidVariants(this.variants, locale);
        this.validVariants.sort(Comparator.comparing(VariantsModel::getSortOrder));
    }

}

package com.mkovacek.aem.core.servlets.products;

import com.day.cq.wcm.api.Page;
import com.mkovacek.aem.core.context.AppAemContextBuilder;
import com.mkovacek.aem.core.context.constants.TestConstants;
import com.mkovacek.aem.core.context.utils.ResourceUtil;
import com.mkovacek.aem.core.services.blobstorage.impl.BlobStorageServiceImpl;
import com.mkovacek.aem.core.services.products.impl.ProductDetailsServiceImpl;
import com.mkovacek.aem.core.services.products.impl.ProductLocalizationServiceImpl;
import com.mkovacek.aem.core.services.products.impl.ProductValidatorServiceImpl;
import com.mkovacek.aem.core.services.resourceresolver.impl.ResourceResolverServiceImpl;
import com.mkovacek.aem.core.services.response.impl.ResponseServiceImpl;

import io.wcm.testing.mock.aem.junit5.AemContext;
import io.wcm.testing.mock.aem.junit5.AemContextExtension;

import org.apache.commons.lang3.StringUtils;
import org.apache.sling.api.resource.ResourceResolverFactory;
import org.apache.sling.testing.mock.sling.servlet.MockRequestPathInfo;
import org.apache.sling.testing.resourceresolver.MockResourceResolverFactory;
import org.junit.jupiter.api.*;
import org.junit.jupiter.api.extension.ExtendWith;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletResponse;

import java.io.IOException;
import java.util.Collections;

import static org.junit.jupiter.api.Assertions.assertAll;
import static org.junit.jupiter.api.Assertions.assertEquals;

@ExtendWith(AemContextExtension.class)
class ProductDetailsServletTest {

    private static final AemContext context = new AppAemContextBuilder()
                                                  .loadResource(TestConstants.HR_HR_LANDING_PAGE_JSON, TestConstants.HR_HR_LANDING_PAGE_PATH)
                                                  .loadResource(TestConstants.DE_AT_LANDING_PAGE_JSON, TestConstants.DE_AT_LANDING_PAGE_PATH)
                                                  .loadResource(TestConstants.FR_FR_LANDING_PAGE_JSON, TestConstants.FR_FR_LANDING_PAGE_PATH)
                                                  .loadResource(TestConstants.PRODUCTS_JSON, TestConstants.PRODUCTS_PATH)
                                                  .registerService(ResourceResolverFactory.class, new MockResourceResolverFactory())
                                                  .registerInjectActivateService(new ResourceResolverServiceImpl())
                                                  .registerInjectActivateService(new ResponseServiceImpl())
                                                  .registerInjectActivateService(new BlobStorageServiceImpl(), Collections.singletonMap("productImagesFolderPath", "https://dummyurl.com/images/products/"))
                                                  .registerInjectActivateService(new ProductValidatorServiceImpl())
                                                  .registerInjectActivateService(new ProductLocalizationServiceImpl())
                                                  .registerInjectActivateService(new ResponseServiceImpl())
                                                  .registerInjectActivateService(new ProductDetailsServiceImpl())
                                                  .build();

    private static final MockRequestPathInfo requestPathInfo = context.requestPathInfo();
    private final ProductDetailsServlet servlet = context.registerInjectActivateService(new ProductDetailsServlet());
    private static final String CONTENT_RESOURCE_PATH = "root/productdetails";
    private static String NOT_FOUND_RESPONSE;
    private static String BAD_REQUEST_RESPONSE;

    @BeforeAll
    static void setUpBeforeAllTests() throws IOException {
        context.addModelsForPackage(TestConstants.SLING_MODELS_PACKAGES);
        requestPathInfo.setExtension("json");
        NOT_FOUND_RESPONSE = ResourceUtil.getExpectedResult(ProductDetailsServlet.class, "responses/not-found-response.json");
        BAD_REQUEST_RESPONSE = ResourceUtil.getExpectedResult(ProductDetailsServlet.class, "responses/bad-request-response.json");
    }

    @BeforeEach
    void setupBeforeEachTest() {
        context.response().resetBuffer();
        requestPathInfo.setSelectorString(ProductDetailsServlet.ALLOWED_SELECTOR);
        requestPathInfo.setSuffix("123456789");
        final Page page = context.pageManager().getPage(TestConstants.HR_HR_LANDING_PAGE_PATH);
        context.request().setResource(page.getContentResource(CONTENT_RESOURCE_PATH));
    }

    @Test
    @DisplayName("GIVEN landing page (en-HR) WHEN servlet is called with not valid selector THEN it returns bad request response in JSON format")
    void testNotValidSelector() throws ServletException, IOException {
        requestPathInfo.setSelectorString(ProductDetailsServlet.ALLOWED_SELECTOR + ".test");
        this.servlet.doGet(context.request(), context.response());

        assertAll(
            () -> assertEquals(HttpServletResponse.SC_BAD_REQUEST, context.response().getStatus()),
            () -> assertEquals(BAD_REQUEST_RESPONSE, context.response().getOutputAsString())
        );
    }

    @Test
    @DisplayName("GIVEN landing page (en-HR) WHEN servlet is called without productId suffix THEN it returns bad request response in JSON format")
    void testNoProductId() throws ServletException, IOException {
        requestPathInfo.setSuffix(StringUtils.EMPTY);
        this.servlet.doGet(context.request(), context.response());

        assertAll(
            () -> assertEquals(HttpServletResponse.SC_BAD_REQUEST, context.response().getStatus()),
            () -> assertEquals(BAD_REQUEST_RESPONSE, context.response().getOutputAsString())
        );
    }

    @Test
    @DisplayName("GIVEN landing page (en-HR) WHEN servlet is called with not existing productId THEN it returns not found response in JSON format")
    void testNotExistingProductId() throws ServletException, IOException {
        requestPathInfo.setSuffix("123abc");
        this.servlet.doGet(context.request(), context.response());

        assertAll(
            () -> assertEquals(HttpServletResponse.SC_OK, context.response().getStatus()),
            () -> assertEquals(NOT_FOUND_RESPONSE, context.response().getOutputAsString())
        );
    }

    @Test
    @DisplayName("GIVEN landing page (en-HR) WHEN servlet is called with existing productId THEN it returns an expected localized (fallback) product details response in JSON format")
    void testProductDetailsInCroatianMarket() throws ServletException, IOException {
        this.servlet.doGet(context.request(), context.response());
        final String expectedProductDetails = ResourceUtil.getExpectedResult(this.getClass(), "responses/product-123456789-hr-HR.json");

        assertAll(
            () -> assertEquals(HttpServletResponse.SC_OK, context.response().getStatus()),
            () -> assertEquals(expectedProductDetails, context.response().getOutputAsString())
        );
    }

    @Test
    @DisplayName("GIVEN landing page (de-AT) WHEN servlet is called with existing productId THEN it returns an expected localized product details response in JSON format")
    void testProductDetailsInAustrianMarket() throws ServletException, IOException {
        this.setPageResource(TestConstants.DE_AT_LANDING_PAGE_PATH);
        this.servlet.doGet(context.request(), context.response());
        final String expectedProductDetails = ResourceUtil.getExpectedResult(this.getClass(), "responses/product-123456789-at-DE.json");

        assertAll(
            () -> assertEquals(HttpServletResponse.SC_OK, context.response().getStatus()),
            () -> assertEquals(expectedProductDetails, context.response().getOutputAsString())
        );
    }

    @Test
    @DisplayName("GIVEN landing page (fr-FR) WHEN servlet is called with existing productId which is not valid for French market THEN it returns not found response in JSON format")
    void testProductDetailsInFrenchMarket() throws ServletException, IOException {
        this.setPageResource(TestConstants.FR_FR_LANDING_PAGE_PATH);
        this.servlet.doGet(context.request(), context.response());

        assertAll(
            () -> assertEquals(HttpServletResponse.SC_OK, context.response().getStatus()),
            () -> assertEquals(NOT_FOUND_RESPONSE, context.response().getOutputAsString())
        );
    }

    private void setPageResource(final String path) {
        final Page page = context.pageManager().getPage(path);
        context.request().setResource(page.getContentResource(CONTENT_RESOURCE_PATH));
    }
}