Out of the box coverage is 36.4% with spring-test

pom.xml

@@ -37,6 +37,12 @@
       <artifactId>mysql-connector-j</artifactId>
       <version>9.0.0</version>
     </dependency>
+    <dependency>
+      <groupId>org.springframework</groupId>
+      <artifactId>spring-test</artifactId>
+      <version>5.3.8</version>
+      <scope>test</scope>
+    </dependency>
     <dependency>
       <groupId>org.mockito</groupId>
       <artifactId>mockito-core</artifactId>

src/test/java/controller/HomeServletDiffblueTest.java

@@ -1,17 +1,21 @@
 package controller;
 
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
 import com.diffblue.cover.annotations.MaintainedByDiffblue;
 import com.diffblue.cover.annotations.MethodsUnderTest;
 import java.io.IOException;
+import java.util.Collection;
+import java.util.Set;
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServletRequest;
-import javax.servlet.http.HttpServletRequestWrapper;
 import javax.servlet.http.HttpServletResponse;
-import javax.servlet.http.HttpServletResponseWrapper;
-import org.junit.Ignore;
 import org.junit.Test;
 import org.junit.experimental.categories.Category;
+import org.springframework.mock.web.MockHttpServletRequest;
+import org.springframework.mock.web.MockHttpServletResponse;
+import org.springframework.mock.web.MockHttpSession;
 
 public class HomeServletDiffblueTest {
   /**
@@ -30,60 +34,124 @@ public void testNewHomeServlet() {
   /**
    * Test {@link HomeServlet#doGet(HttpServletRequest, HttpServletResponse)}.
    * <ul>
-   *   <li>When {@link HttpServletRequestWrapper#HttpServletRequestWrapper(HttpServletRequest)} with request is {@code null}.</li>
+   *   <li>Given {@link MockHttpSession#MockHttpSession()}.</li>
    * </ul>
    * <p>
    * Method under test: {@link HomeServlet#doGet(HttpServletRequest, HttpServletResponse)}
    */
   @Test
-  @Ignore("TODO: Complete this test")
   @Category(MaintainedByDiffblue.class)
   @MethodsUnderTest({"void HomeServlet.doGet(HttpServletRequest, HttpServletResponse)"})
-  public void testDoGet_whenHttpServletRequestWrapperWithRequestIsNull() throws IOException, ServletException {
-    // TODO: Diffblue Cover was only able to create a partial test for this method:
-    //   Reason: No inputs found that don't throw a trivial exception.
-    //   Diffblue Cover tried to run the arrange/act section, but the method under
-    //   test threw
-    //   java.lang.IllegalArgumentException: Request cannot be null
-    //       at javax.servlet.ServletRequestWrapper.<init>(ServletRequestWrapper.java:50)
-    //       at javax.servlet.http.HttpServletRequestWrapper.<init>(HttpServletRequestWrapper.java:47)
-    //   See https://diff.blue/R013 to resolve this issue.
+  public void testDoGet_givenMockHttpSession() throws IOException, ServletException {
+    // Arrange
+    HomeServlet homeServlet = new HomeServlet();
+
+    MockHttpServletRequest request = new MockHttpServletRequest();
+    request.setSession(new MockHttpSession());
+    MockHttpServletResponse response = new MockHttpServletResponse();
+
+    // Act
+    homeServlet.doGet(request, response);
 
+    // Assert
+    Collection<String> headerNames = response.getHeaderNames();
+    assertEquals(1, headerNames.size());
+    assertTrue(headerNames instanceof Set);
+    assertEquals("login", response.getRedirectedUrl());
+    assertEquals(302, response.getStatus());
+    assertTrue(headerNames.contains("Location"));
+    assertTrue(response.isCommitted());
+  }
+
+  /**
+   * Test {@link HomeServlet#doGet(HttpServletRequest, HttpServletResponse)}.
+   * <ul>
+   *   <li>Then {@link MockHttpServletResponse} (default constructor) HeaderNames size is one.</li>
+   * </ul>
+   * <p>
+   * Method under test: {@link HomeServlet#doGet(HttpServletRequest, HttpServletResponse)}
+   */
+  @Test
+  @Category(MaintainedByDiffblue.class)
+  @MethodsUnderTest({"void HomeServlet.doGet(HttpServletRequest, HttpServletResponse)"})
+  public void testDoGet_thenMockHttpServletResponseHeaderNamesSizeIsOne() throws IOException, ServletException {
     // Arrange
     HomeServlet homeServlet = new HomeServlet();
-    HttpServletRequestWrapper request = new HttpServletRequestWrapper(null);
+    MockHttpServletRequest request = new MockHttpServletRequest();
+    MockHttpServletResponse response = new MockHttpServletResponse();
 
     // Act
-    homeServlet.doGet(request, new HttpServletResponseWrapper(null));
+    homeServlet.doGet(request, response);
+
+    // Assert
+    Collection<String> headerNames = response.getHeaderNames();
+    assertEquals(1, headerNames.size());
+    assertTrue(headerNames instanceof Set);
+    assertEquals("login", response.getRedirectedUrl());
+    assertEquals(302, response.getStatus());
+    assertTrue(headerNames.contains("Location"));
+    assertTrue(response.isCommitted());
   }
 
   /**
    * Test {@link HomeServlet#doPost(HttpServletRequest, HttpServletResponse)}.
    * <ul>
-   *   <li>When {@link HttpServletRequestWrapper#HttpServletRequestWrapper(HttpServletRequest)} with request is {@code null}.</li>
+   *   <li>Given {@link MockHttpSession#MockHttpSession()}.</li>
    * </ul>
    * <p>
    * Method under test: {@link HomeServlet#doPost(HttpServletRequest, HttpServletResponse)}
    */
   @Test
-  @Ignore("TODO: Complete this test")
   @Category(MaintainedByDiffblue.class)
   @MethodsUnderTest({"void HomeServlet.doPost(HttpServletRequest, HttpServletResponse)"})
-  public void testDoPost_whenHttpServletRequestWrapperWithRequestIsNull() throws IOException, ServletException {
-    // TODO: Diffblue Cover was only able to create a partial test for this method:
-    //   Reason: No inputs found that don't throw a trivial exception.
-    //   Diffblue Cover tried to run the arrange/act section, but the method under
-    //   test threw
-    //   java.lang.IllegalArgumentException: Request cannot be null
-    //       at javax.servlet.ServletRequestWrapper.<init>(ServletRequestWrapper.java:50)
-    //       at javax.servlet.http.HttpServletRequestWrapper.<init>(HttpServletRequestWrapper.java:47)
-    //   See https://diff.blue/R013 to resolve this issue.
+  public void testDoPost_givenMockHttpSession() throws IOException, ServletException {
+    // Arrange
+    HomeServlet homeServlet = new HomeServlet();
+
+    MockHttpServletRequest request = new MockHttpServletRequest();
+    request.setSession(new MockHttpSession());
+    MockHttpServletResponse response = new MockHttpServletResponse();
+
+    // Act
+    homeServlet.doPost(request, response);
 
+    // Assert
+    Collection<String> headerNames = response.getHeaderNames();
+    assertEquals(1, headerNames.size());
+    assertTrue(headerNames instanceof Set);
+    assertEquals("login", response.getRedirectedUrl());
+    assertEquals(302, response.getStatus());
+    assertTrue(headerNames.contains("Location"));
+    assertTrue(response.isCommitted());
+  }
+
+  /**
+   * Test {@link HomeServlet#doPost(HttpServletRequest, HttpServletResponse)}.
+   * <ul>
+   *   <li>Then {@link MockHttpServletResponse} (default constructor) HeaderNames size is one.</li>
+   * </ul>
+   * <p>
+   * Method under test: {@link HomeServlet#doPost(HttpServletRequest, HttpServletResponse)}
+   */
+  @Test
+  @Category(MaintainedByDiffblue.class)
+  @MethodsUnderTest({"void HomeServlet.doPost(HttpServletRequest, HttpServletResponse)"})
+  public void testDoPost_thenMockHttpServletResponseHeaderNamesSizeIsOne() throws IOException, ServletException {
     // Arrange
     HomeServlet homeServlet = new HomeServlet();
-    HttpServletRequestWrapper request = new HttpServletRequestWrapper(null);
+    MockHttpServletRequest request = new MockHttpServletRequest();
+    MockHttpServletResponse response = new MockHttpServletResponse();
 
     // Act
-    homeServlet.doPost(request, new HttpServletResponseWrapper(null));
+    homeServlet.doPost(request, response);
+
+    // Assert
+    Collection<String> headerNames = response.getHeaderNames();
+    assertEquals(1, headerNames.size());
+    assertTrue(headerNames instanceof Set);
+    assertEquals("login", response.getRedirectedUrl());
+    assertEquals(302, response.getStatus());
+    assertTrue(headerNames.contains("Location"));
+    assertTrue(response.isCommitted());
   }
 }

src/test/java/controller/LoginServletDiffblueTest.java

@@ -1,17 +1,26 @@
 package controller;
 
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNull;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.atLeast;
+import static org.mockito.Mockito.doNothing;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
 import com.diffblue.cover.annotations.MaintainedByDiffblue;
 import com.diffblue.cover.annotations.MethodsUnderTest;
 import java.io.IOException;
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServletRequest;
-import javax.servlet.http.HttpServletRequestWrapper;
 import javax.servlet.http.HttpServletResponse;
-import javax.servlet.http.HttpServletResponseWrapper;
-import org.junit.Ignore;
 import org.junit.Test;
 import org.junit.experimental.categories.Category;
+import org.mockito.Mockito;
+import org.springframework.mock.web.MockHttpServletRequest;
+import org.springframework.mock.web.MockHttpServletResponse;
+import org.springframework.mock.web.MockHttpSession;
+import org.springframework.mock.web.MockRequestDispatcher;
 
 public class LoginServletDiffblueTest {
   /**
@@ -30,60 +39,114 @@ public void testNewLoginServlet() {
   /**
    * Test {@link LoginServlet#doGet(HttpServletRequest, HttpServletResponse)}.
    * <ul>
-   *   <li>When {@link HttpServletRequestWrapper#HttpServletRequestWrapper(HttpServletRequest)} with request is {@code null}.</li>
+   *   <li>Given {@link MockHttpSession#MockHttpSession()}.</li>
    * </ul>
    * <p>
    * Method under test: {@link LoginServlet#doGet(HttpServletRequest, HttpServletResponse)}
    */
   @Test
-  @Ignore("TODO: Complete this test")
   @Category(MaintainedByDiffblue.class)
   @MethodsUnderTest({"void LoginServlet.doGet(HttpServletRequest, HttpServletResponse)"})
-  public void testDoGet_whenHttpServletRequestWrapperWithRequestIsNull() throws IOException, ServletException {
-    // TODO: Diffblue Cover was only able to create a partial test for this method:
-    //   Reason: No inputs found that don't throw a trivial exception.
-    //   Diffblue Cover tried to run the arrange/act section, but the method under
-    //   test threw
-    //   java.lang.IllegalArgumentException: Request cannot be null
-    //       at javax.servlet.ServletRequestWrapper.<init>(ServletRequestWrapper.java:50)
-    //       at javax.servlet.http.HttpServletRequestWrapper.<init>(HttpServletRequestWrapper.java:47)
-    //   See https://diff.blue/R013 to resolve this issue.
+  public void testDoGet_givenMockHttpSession() throws IOException, ServletException {
+    // Arrange
+    LoginServlet loginServlet = new LoginServlet();
+
+    MockHttpServletRequest request = new MockHttpServletRequest();
+    request.setSession(new MockHttpSession());
+    MockHttpServletResponse response = new MockHttpServletResponse();
+
+    // Act
+    loginServlet.doGet(request, response);
 
+    // Assert
+    assertEquals("WEB-INF/login.jsp", response.getForwardedUrl());
+  }
+
+  /**
+   * Test {@link LoginServlet#doGet(HttpServletRequest, HttpServletResponse)}.
+   * <ul>
+   *   <li>Then {@link MockHttpServletResponse} (default constructor) ForwardedUrl is {@code WEB-INF/login.jsp}.</li>
+   * </ul>
+   * <p>
+   * Method under test: {@link LoginServlet#doGet(HttpServletRequest, HttpServletResponse)}
+   */
+  @Test
+  @Category(MaintainedByDiffblue.class)
+  @MethodsUnderTest({"void LoginServlet.doGet(HttpServletRequest, HttpServletResponse)"})
+  public void testDoGet_thenMockHttpServletResponseForwardedUrlIsWebInfLoginJsp() throws IOException, ServletException {
     // Arrange
     LoginServlet loginServlet = new LoginServlet();
-    HttpServletRequestWrapper request = new HttpServletRequestWrapper(null);
+    MockHttpServletRequest request = new MockHttpServletRequest();
+    MockHttpServletResponse response = new MockHttpServletResponse();
 
     // Act
-    loginServlet.doGet(request, new HttpServletResponseWrapper(null));
+    loginServlet.doGet(request, response);
+
+    // Assert
+    assertEquals("WEB-INF/login.jsp", response.getForwardedUrl());
   }
 
   /**
    * Test {@link LoginServlet#doPost(HttpServletRequest, HttpServletResponse)}.
    * <ul>
-   *   <li>When {@link HttpServletRequestWrapper#HttpServletRequestWrapper(HttpServletRequest)} with request is {@code null}.</li>
+   *   <li>Then {@link MockHttpServletResponse} (default constructor) ForwardedUrl is {@code Resource}.</li>
    * </ul>
    * <p>
    * Method under test: {@link LoginServlet#doPost(HttpServletRequest, HttpServletResponse)}
    */
   @Test
-  @Ignore("TODO: Complete this test")
   @Category(MaintainedByDiffblue.class)
   @MethodsUnderTest({"void LoginServlet.doPost(HttpServletRequest, HttpServletResponse)"})
-  public void testDoPost_whenHttpServletRequestWrapperWithRequestIsNull() throws IOException, ServletException {
-    // TODO: Diffblue Cover was only able to create a partial test for this method:
-    //   Reason: No inputs found that don't throw a trivial exception.
-    //   Diffblue Cover tried to run the arrange/act section, but the method under
-    //   test threw
-    //   java.lang.IllegalArgumentException: Request cannot be null
-    //       at javax.servlet.ServletRequestWrapper.<init>(ServletRequestWrapper.java:50)
-    //       at javax.servlet.http.HttpServletRequestWrapper.<init>(HttpServletRequestWrapper.java:47)
-    //   See https://diff.blue/R013 to resolve this issue.
+  public void testDoPost_thenMockHttpServletResponseForwardedUrlIsResource() throws IOException, ServletException {
+    // Arrange
+    LoginServlet loginServlet = new LoginServlet();
+    MockHttpServletRequest request = mock(MockHttpServletRequest.class);
+    when(request.getRequestDispatcher(Mockito.<String>any())).thenReturn(new MockRequestDispatcher("Resource"));
+    doNothing().when(request).setAttribute(Mockito.<String>any(), Mockito.<Object>any());
+    when(request.getParameter(Mockito.<String>any())).thenReturn("https://example.org/example");
+    doNothing().when(request).removeAttribute(Mockito.<String>any());
+    MockHttpServletResponse response = new MockHttpServletResponse();
 
+    // Act
+    loginServlet.doPost(request, response);
+
+    // Assert
+    verify(request, atLeast(1)).getParameter(Mockito.<String>any());
+    verify(request).getRequestDispatcher(eq("WEB-INF/login.jsp"));
+    verify(request).removeAttribute(eq("msg"));
+    verify(request, atLeast(1)).setAttribute(Mockito.<String>any(), Mockito.<Object>any());
+    assertEquals("Resource", response.getForwardedUrl());
+  }
+
+  /**
+   * Test {@link LoginServlet#doPost(HttpServletRequest, HttpServletResponse)}.
+   * <ul>
+   *   <li>Then {@link MockHttpServletResponse} (default constructor) ForwardedUrl is {@code Resource}.</li>
+   * </ul>
+   * <p>
+   * Method under test: {@link LoginServlet#doPost(HttpServletRequest, HttpServletResponse)}
+   */
+  @Test
+  @Category(MaintainedByDiffblue.class)
+  @MethodsUnderTest({"void LoginServlet.doPost(HttpServletRequest, HttpServletResponse)"})
+  public void testDoPost_thenMockHttpServletResponseForwardedUrlIsResource2() throws IOException, ServletException {
     // Arrange
     LoginServlet loginServlet = new LoginServlet();
-    HttpServletRequestWrapper request = new HttpServletRequestWrapper(null);
+    MockHttpServletRequest request = mock(MockHttpServletRequest.class);
+    when(request.getRequestDispatcher(Mockito.<String>any())).thenReturn(new MockRequestDispatcher("Resource"));
+    doNothing().when(request).setAttribute(Mockito.<String>any(), Mockito.<Object>any());
+    when(request.getParameter(Mockito.<String>any())).thenReturn("");
+    doNothing().when(request).removeAttribute(Mockito.<String>any());
+    MockHttpServletResponse response = new MockHttpServletResponse();
 
     // Act
-    loginServlet.doPost(request, new HttpServletResponseWrapper(null));
+    loginServlet.doPost(request, response);
+
+    // Assert
+    verify(request, atLeast(1)).getParameter(Mockito.<String>any());
+    verify(request).getRequestDispatcher(eq("WEB-INF/login.jsp"));
+    verify(request).removeAttribute(eq("msg"));
+    verify(request, atLeast(1)).setAttribute(Mockito.<String>any(), Mockito.<Object>any());
+    assertEquals("Resource", response.getForwardedUrl());
   }
 }