JUnit 4: AEM Sling Servlet Unit Test Example Using wcm.io AEM Mocks, Servlet by Resource Type

package com.sourcedcode.core.servlets;

import com.day.cq.wcm.api.Page;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.apache.sling.api.SlingHttpServletRequest;
import org.apache.sling.api.SlingHttpServletResponse;
import org.apache.sling.api.resource.Resource;
import org.apache.sling.api.resource.ResourceResolver;
import org.apache.sling.api.servlets.SlingSafeMethodsServlet;
import org.apache.sling.servlets.annotations.SlingServletResourceTypes;
import org.osgi.service.component.annotations.Component;

import javax.servlet.Servlet;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import static com.day.crx.packaging.JSONResponse.APPLICATION_JSON_UTF8;
import static org.apache.sling.api.servlets.HttpConstants.METHOD_GET;

/**
 * A demonstration sling servlet resource type class to demonstrate unit testing.
 * Appending ".example.json" on any resource will activate the doGet() method below, and return Json data.
 * Json Data returned is data from the immediate children of the "/content/we-retail', parent resource node.
 */
@Component(service = Servlet.class)
@SlingServletResourceTypes(
        resourceTypes = "sling/servlet/default",
        methods = METHOD_GET,
        extensions = "json",
        selectors = "example")
public class SlingServletResourceTypesExampleDS14Servlet extends SlingSafeMethodsServlet {

    @Override
    protected void doGet(SlingHttpServletRequest req, SlingHttpServletResponse res) throws IOException {
        res.setContentType(APPLICATION_JSON_UTF8);
        res.setStatus(SlingHttpServletResponse.SC_OK);
        List<PageItem> pageItems = getPageItems(req);
        String json = new ObjectMapper().writeValueAsString(pageItems);
        res.getWriter().write(json);
    }

    private List<PageItem> getPageItems(SlingHttpServletRequest req) {
        List<PageItem> pageItems = new ArrayList<>();
        ResourceResolver resolver = req.getResourceResolver();
        Resource weRetail = resolver.getResource("/content/we-retail");
        if (weRetail != null) {
            Iterator<Resource> it = weRetail.listChildren();
            while (it.hasNext()) {
                Resource resource = it.next();
                if (resource.getResourceType().equalsIgnoreCase(com.day.cq.wcm.api.NameConstants.NT_PAGE)) {
                    Page page = resource.adaptTo(Page.class);
                    if (page != null) {
                        pageItems.add((new PageItem(page.getTitle(), resource.getPath())));
                    }
                }
            }
        }
        return pageItems;
    }

    /**
     * Inner class PageItem, for creating PageItem objects.
     */
    public class PageItem {

        private String pageTitle;

        private String pagePath;

        PageItem(String pageTitle, String pagePath) {
            this.pageTitle = pageTitle;
            this.pagePath = pagePath;
        }

        public String getPageTitle() {
            return pageTitle;
        }

        public String getPagePath() {
            return pagePath;
        }
    }
}

package com.sourcedcode.core.servlets;

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import io.wcm.testing.mock.aem.junit.AemContext;
import org.apache.sling.testing.mock.sling.ResourceResolverType;
import org.apache.sling.testing.mock.sling.servlet.MockSlingHttpServletRequest;
import org.apache.sling.testing.mock.sling.servlet.MockSlingHttpServletResponse;
import org.junit.Before;
import org.junit.Rule;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.junit.MockitoJUnitRunner;

import java.io.IOException;

import static com.day.crx.packaging.JSONResponse.APPLICATION_JSON_UTF8;
import static junitx.framework.Assert.assertEquals;
import static org.junit.Assert.assertTrue;

@RunWith(MockitoJUnitRunner.class)
public class SlingServletResourceTypesExampleDS14ServletTest {

    @Rule
    public final AemContext context = new AemContext(ResourceResolverType.JCR_MOCK);

    @Mock
    private MockSlingHttpServletRequest req;

    @Mock
    private MockSlingHttpServletResponse res;

    @InjectMocks
    private SlingServletResourceTypesExampleDS14Servlet underTest;

    @Before
    public void setup() {
        underTest = new SlingServletResourceTypesExampleDS14Servlet();
        req = context.request();
        res = context.response();
    }

    @Test
    public void doGet_shouldReturnHeaderAsExpected() throws IOException {
        underTest.doGet(req, res);
        assertEquals(res.getContentType(), APPLICATION_JSON_UTF8);
    }

    @Test
    public void doGet_shouldReturnPageItemListJsonAsExpected_0() throws IOException {
        underTest.doGet(req, res);
        String jsonString = res.getOutputAsString();
        ObjectMapper mapper = new ObjectMapper();
        JsonNode actualObj = mapper.readTree(jsonString);
        assertEquals(0, actualObj.size());
    }

    @Test
    public void doGet_shouldReturnPageItemJsonAsExpected_properties_values() throws IOException {
        createPagesInJcrMock();
        underTest.doGet(req, res);
        String jsonString = res.getOutputAsString();
        ObjectMapper mapper = new ObjectMapper();
        JsonNode actualObj = mapper.readTree(jsonString);
        JsonNode firstItem = actualObj.get(0);
        assertTrue(firstItem.has("pageTitle"));
        assertTrue(firstItem.has("pagePath"));
        assertEquals( "United states", firstItem.get("pageTitle").textValue());
        assertEquals("/content/we-retail/us", firstItem.get("pagePath").textValue());
    }

    /**
     * Test helper method to create 3 pages in the on-memory JCR Mock instance.
     */
    private void createPagesInJcrMock() {
        context.create().page("/content/we-retail", "/", "We Retail");
        context.create().page("/content/we-retail/us", "/", "United states");
        context.create().page("/content/we-retail/ca", "/", "Canada");
    }
}