Added initial unit tests

Jenkinsfile

@@ -43,6 +43,9 @@ def upstreamProjects = [
   'servlet', // <groupId>com.semanticcms</groupId><artifactId>semanticcms-core-servlet</artifactId>
   // No Jenkins: <groupId>com.github.spotbugs</groupId><artifactId>spotbugs-annotations</artifactId>
 
+  // Test Direct
+  // No Jenkins: <groupId>junit</groupId><artifactId>junit</artifactId>
+
   // BOM
   '../../oss/javaee-web-api-bom', // <groupId>com.aoapps</groupId><artifactId>javaee-web-api-bom</artifactId>
 ]

pom.xml

@@ -192,6 +192,12 @@ along with semanticcms-core-sitemap.  If not, see <https://www.gnu.org/licenses/
                       <includes>element-list, package-list</includes>
                       <outputDirectory>${project.build.directory}/offlineLinks/com.github.spotbugs/spotbugs-annotations</outputDirectory>
                     </artifactItem>
+                    <!-- Test Direct -->
+                    <artifactItem>
+                      <groupId>junit</groupId><artifactId>junit</artifactId><classifier>javadoc</classifier>
+                      <includes>element-list, package-list</includes>
+                      <outputDirectory>${project.build.directory}/offlineLinks/junit/junit</outputDirectory>
+                    </artifactItem>
                   </artifactItems>
                 </configuration>
               </execution>
@@ -255,6 +261,11 @@ along with semanticcms-core-sitemap.  If not, see <https://www.gnu.org/licenses/
                   <url>https://javadoc.io/doc/com.github.spotbugs/spotbugs-annotations/${spotbugs-annotations.version}/</url>
                   <location>${project.build.directory}/offlineLinks/com.github.spotbugs/spotbugs-annotations</location>
                 </offlineLink>
+                <!-- Test Direct -->
+                <offlineLink>
+                  <url>https://junit.org/junit4/javadoc/latest/</url>
+                  <location>${project.build.directory}/offlineLinks/junit/junit</location>
+                </offlineLink>
               </offlineLinks>
             </configuration>
           </plugin>
@@ -398,6 +409,18 @@ along with semanticcms-core-sitemap.  If not, see <https://www.gnu.org/licenses/
       <dependency>
         <groupId>com.google.code.findbugs</groupId><artifactId>jsr305</artifactId><version>3.0.2</version>
       </dependency>
+      <!-- Test Direct -->
+      <dependency>
+        <groupId>junit</groupId><artifactId>junit</artifactId><version>4.13.2</version>
+      </dependency>
+      <!-- Test Transitive -->
+      <dependency>
+        <groupId>org.hamcrest</groupId><artifactId>hamcrest</artifactId><version>2.2</version>
+      </dependency>
+      <dependency>
+        <!-- Shim for junit 4.13.2 -->
+        <groupId>org.hamcrest</groupId><artifactId>hamcrest-core</artifactId><version>2.2</version>
+      </dependency>
       <!-- Imports -->
       <dependency>
         <groupId>com.aoapps</groupId><artifactId>javaee-web-api-bom</artifactId><version>7.0.1-POST-SNAPSHOT</version>
@@ -452,6 +475,11 @@ along with semanticcms-core-sitemap.  If not, see <https://www.gnu.org/licenses/
       <groupId>com.github.spotbugs</groupId><artifactId>spotbugs-annotations</artifactId>
       <optional>true</optional>
     </dependency>
+    <!-- Test Direct -->
+    <dependency>
+      <groupId>junit</groupId><artifactId>junit</artifactId>
+      <scope>test</scope>
+    </dependency>
     <!-- Imports (Reactor build order only) -->
     <dependency>
       <groupId>com.aoapps</groupId><artifactId>javaee-web-api-bom</artifactId><version>7.0.1-POST-SNAPSHOT</version>

src/main/java/com/semanticcms/core/sitemap/SiteMapRobotsTxtServlet.java

@@ -64,12 +64,8 @@ public class SiteMapRobotsTxtServlet extends HttpServlet {
 
   static {
     try {
-      ClassLoader cl = Thread.currentThread().getContextClassLoader();
-      if (cl == null) {
-        cl = ClassLoader.getSystemClassLoader();
-      }
-      String classFilename = '/' + SiteMapRobotsTxtServlet.class.getName().replace('.', '/') + ".class";
-      URL classFile = cl.getResource(classFilename);
+      String classFilename = SiteMapRobotsTxtServlet.class.getSimpleName() + ".class";
+      URL classFile = SiteMapRobotsTxtServlet.class.getResource(classFilename);
       if (classFile == null) {
         throw new IOException("Unable to find class file: " + classFilename);
       }

src/test/java/com/semanticcms/core/sitemap/SiteMapRobotsTxtServletTest.java

@@ -0,0 +1,49 @@
+/*
+ * semanticcms-core-sitemap - Automatic sitemaps for SemanticCMS.
+ * Copyright (C) 2023  AO Industries, Inc.
+ *     support@aoindustries.com
+ *     7262 Bull Pen Cir
+ *     Mobile, AL 36695
+ *
+ * This file is part of semanticcms-core-sitemap.
+ *
+ * semanticcms-core-sitemap is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * semanticcms-core-sitemap is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with semanticcms-core-sitemap.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.semanticcms.core.sitemap;
+
+import static org.junit.Assert.assertNotEquals;
+
+import java.lang.reflect.Field;
+import org.junit.Test;
+
+/**
+ * Tests {@link SiteMapRobotsTxtServlet}.
+ */
+public class SiteMapRobotsTxtServletTest {
+
+  private static long getLastModified() throws ReflectiveOperationException {
+    Field field = SiteMapRobotsTxtServlet.class.getDeclaredField("LAST_MODIFIED");
+    field.setAccessible(true);
+    return (long) field.get(null);
+  }
+
+  /**
+   * Tests {@link SiteMapRobotsTxtServlet#LAST_MODIFIED}.
+   */
+  @Test
+  public void testLastModified() throws ReflectiveOperationException {
+    assertNotEquals(0, getLastModified());
+  }
+}