package mockit;
   
   import static org.junit.jupiter.api.Assertions.assertEquals;
   import static org.junit.jupiter.api.Assertions.assertFalse;
   import static org.junit.jupiter.api.Assertions.assertNotNull;
   import static org.junit.jupiter.api.Assertions.assertNull;
   import static org.junit.jupiter.api.Assertions.assertSame;
   import static org.junit.jupiter.api.Assertions.assertTrue;
   import static org.junit.jupiter.api.Assertions.fail;
  
  import java.io.ByteArrayOutputStream;
  import java.io.File;
  import java.io.IOException;
  import java.io.OutputStream;
  import java.net.HttpURLConnection;
  import java.net.URL;
  import java.net.URLConnection;
  import java.net.URLStreamHandler;
  import java.nio.file.Path;
  
  import org.junit.jupiter.api.Test;
  
  /**
   * The Class ClassLoadingAndJREMocksTest.
   */
  class ClassLoadingAndJREMocksTest {
  
      /**
       * The Class Foo.
       */
      static class Foo {
      }
  
      /**
       * Fake file.
       */
      @Test
      void fakeFile() {
          new MockUp<File>() {
              @Mock
              void $init(String name) {
              } // not necessary, except to verify non-occurrence of NPE
  
              @Mock
              boolean exists() {
                  return true;
              }
          };
  
          new Foo(); // causes a class load
          assertTrue(Path.of("filePath").toFile().exists());
      }
  
      /**
       * Fake file safely using reentrant fake method.
       */
      @Test
      void fakeFileSafelyUsingReentrantFakeMethod() {
          new MockUp<File>() {
              @Mock
              boolean exists(Invocation inv) {
                  File it = inv.getInvokedInstance();
                  return "testFile".equals(it.getName()) || inv.<Boolean> proceed();
              }
          };
  
          checkForTheExistenceOfSeveralFiles();
      }
  
      /**
       * Check for the existence of several files.
       */
      void checkForTheExistenceOfSeveralFiles() {
          assertFalse(Path.of("someOtherFile").toFile().exists());
          assertTrue(Path.of("testFile").toFile().exists());
          assertFalse(Path.of("yet/another/file").toFile().exists());
          assertTrue(Path.of("testFile").toFile().exists());
      }
  
      /**
       * Fake file safely using proceed.
       */
      @Test
      void fakeFileSafelyUsingProceed() {
          new MockUp<File>() {
              @Mock
              boolean exists(Invocation inv) {
                  File it = inv.getInvokedInstance();
                  return "testFile".equals(it.getName()) || inv.<Boolean> proceed();
              }
          };
  
          checkForTheExistenceOfSeveralFiles();
      }
  
      /**
       * Attempt to mock non mockable JRE class.
       *
       * @param mock
      *            the mock
      */
     @Test
     void attemptToMockNonMockableJREClass(@Mocked Integer mock) {
         assertNull(mock);
     }
 
     /**
      * Mock URL and URL connection.
      *
      * @param mockUrl
      *            the mock url
      * @param mockConnection
      *            the mock connection
      *
      * @throws Exception
      *             the exception
      */
     @Test
     void mockURLAndURLConnection(@Mocked URL mockUrl, @Mocked URLConnection mockConnection) throws Exception {
         URLConnection conn = mockUrl.openConnection();
 
         assertSame(mockConnection, conn);
     }
 
     /**
      * Mock URL and http URL connection.
      *
      * @param mockUrl
      *            the mock url
      * @param mockConnection
      *            the mock connection
      *
      * @throws Exception
      *             the exception
      */
     @Test
     void mockURLAndHttpURLConnection(@Mocked URL mockUrl, @Mocked HttpURLConnection mockConnection) throws Exception {
         HttpURLConnection conn = (HttpURLConnection) mockUrl.openConnection();
         assertSame(mockConnection, conn);
     }
 
     /**
      * Mock URL and http URL connection with dynamic mock.
      *
      * @param mockHttpConnection
      *            the mock http connection
      *
      * @throws Exception
      *             the exception
      */
     @Test
     void mockURLAndHttpURLConnectionWithDynamicMock(@Mocked final HttpURLConnection mockHttpConnection)
             throws Exception {
         final URL url = new URL("http://nowhere");
 
         new Expectations(url) {
             {
                 url.openConnection();
                 result = mockHttpConnection;
                 mockHttpConnection.getOutputStream();
                 result = new ByteArrayOutputStream();
             }
         };
 
         // Code under test:
         HttpURLConnection conn = (HttpURLConnection) url.openConnection();
         conn.setDoOutput(true);
         conn.setRequestMethod("PUT");
         OutputStream out = conn.getOutputStream();
 
         assertNotNull(out);
 
         new Verifications() {
             {
                 mockHttpConnection.setDoOutput(true);
                 mockHttpConnection.setRequestMethod("PUT");
             }
         };
     }
 
     /**
      * Read resource content.
      *
      * @return the string
      *
      * @throws IOException
      *             Signals that an I/O exception has occurred.
      */
     String readResourceContent() throws IOException {
         URL url = new URL("http://remoteHost/aResource");
         URLConnection connection = url.openConnection();
 
         connection.setConnectTimeout(1000);
         connection.connect();
 
         return connection.getContent().toString();
     }
 
     /**
      * Cascading mocked URL with injectable cascaded URL connection.
      *
      * @param anyUrl
      *            the any url
      * @param cascadedUrlConnection
      *            the cascaded url connection
      *
      * @throws Exception
      *             the exception
      */
     @Test
     void cascadingMockedURLWithInjectableCascadedURLConnection(@Mocked URL anyUrl,
             @Injectable final URLConnection cascadedUrlConnection) throws Exception {
         String testContent = recordURLConnectionToReturnContent(cascadedUrlConnection);
 
         String content = readResourceContent();
 
         assertEquals(testContent, content);
     }
 
     /**
      * Record URL connection to return content.
      *
      * @param urlConnection
      *            the url connection
      *
      * @return the string
      *
      * @throws IOException
      *             Signals that an I/O exception has occurred.
      */
     String recordURLConnectionToReturnContent(final URLConnection urlConnection) throws IOException {
         final String testContent = "testing";
         new Expectations() {
             {
                 urlConnection.getContent();
                 result = testContent;
             }
         };
         return testContent;
     }
 
     /**
      * Fake URL using injectable URL connection.
      *
      * @param urlConnection
      *            the url connection
      *
      * @throws Exception
      *             the exception
      */
     @Test
     void fakeURLUsingInjectableURLConnection(@Injectable final URLConnection urlConnection) throws Exception {
         final String testContent = recordURLConnectionToReturnContent(urlConnection);
         new MockUp<URL>() {
             @Mock
             void $init(URL context, String spec, URLStreamHandler handler) {
             }
 
             @Mock
             URLConnection openConnection() {
                 return urlConnection;
             }
         };
 
         String content = readResourceContent();
 
         assertEquals(testContent, content);
     }
 
     /**
      * Attempt to mock JRE class that is never mockable.
      *
      * @param mockClass
      *            the mock class
      */
     @org.junit.Test(expected = IllegalArgumentException.class)
     public void attemptToMockJREClassThatIsNeverMockable(@Mocked Class<?> mockClass) {
         fail("Should never get here");
     }
 
 }