Fix FtpFileObject.exists() returning true for root-level folders after

connection drop #757

- Use static imports for JUnit only
- Sort members
- Reduce vertical whitespace

Author: garydgregory

commons-vfs2/src/test/java/org/apache/commons/vfs2/provider/ftp/FtpRootExistsOnDisconnectTest.java

@@ -14,8 +14,12 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.apache.commons.vfs2.provider.ftp;
 
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
 import java.time.Duration;
 
 import org.apache.commons.vfs2.FileObject;
@@ -24,21 +28,28 @@
 import org.apache.commons.vfs2.VfsTestUtils;
 import org.apache.commons.vfs2.impl.DefaultFileSystemManager;
 import org.junit.jupiter.api.AfterEach;
-import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
 /**
  * Tests {@link FtpFileObject#exists()} for root-level FTP folders where {@code getParent()} returns {@code null}.
  * <p>
- * Regression test for the bug in {@link FtpFileObject} where {@code setFTPFile()} blindly assumed that root-level
- * directories exist ({@code setType(DIRECTORY_TYPE)}) without verifying on the server. This caused {@code exists()} to
- * return {@code true} even after the FTP connection was lost, while non-root folders correctly reported the connection
- * failure via {@link FileSystemException}.
+ * Regression test for the bug in {@link FtpFileObject} where {@code setFTPFile()} blindly assumed that root-level directories exist
+ * ({@code setType(DIRECTORY_TYPE)}) without verifying on the server. This caused {@code exists()} to return {@code true} even after the FTP connection was
+ * lost, while non-root folders correctly reported the connection failure via {@link FileSystemException}.
  * </p>
  */
 public class FtpRootExistsOnDisconnectTest {
 
+    private static FileSystemOptions createOptions() {
+        final FileSystemOptions options = new FileSystemOptions();
+        final FtpFileSystemConfigBuilder builder = FtpFileSystemConfigBuilder.getInstance();
+        builder.setUserDirIsRoot(options, true);
+        builder.setPassiveMode(options, true);
+        builder.setConnectTimeout(options, Duration.ofSeconds(10));
+        return options;
+    }
+
     @BeforeEach
     public void setUp() throws Exception {
         FtpProviderTest.setUpClass(VfsTestUtils.getTestDirectory(), null, null);
@@ -49,26 +60,15 @@ public void tearDown() {
         FtpProviderTest.tearDownClass();
     }
 
-    private static FileSystemOptions createOptions() {
-        final FileSystemOptions options = new FileSystemOptions();
-        final FtpFileSystemConfigBuilder builder = FtpFileSystemConfigBuilder.getInstance();
-        builder.setUserDirIsRoot(options, true);
-        builder.setPassiveMode(options, true);
-        builder.setConnectTimeout(options, Duration.ofSeconds(10));
-        return options;
-    }
-
     /**
-     * Tests that {@code exists()} returns {@code true} when the server is running, and does not silently return
-     * {@code true} after the FTP connection is lost.
+     * Tests that {@code exists()} returns {@code true} when the server is running, and does not silently return {@code true} after the FTP connection is lost.
      * <p>
-     * With {@code userDirIsRoot=true}, the root's {@code getParent()} returns {@code null}, which triggers the
-     * {@code verifyRootDirectory()} code path in {@code setFTPFile()}.
+     * With {@code userDirIsRoot=true}, the root's {@code getParent()} returns {@code null}, which triggers the {@code verifyRootDirectory()} code path in
+     * {@code setFTPFile()}.
      * </p>
      * <p>
-     * Before the fix, {@code setFTPFile()} set {@code type=DIRECTORY} when {@code getParent()} returned {@code null},
-     * without contacting the server. After the fix, {@code setFTPFile()} uses CWD to verify, which fails on a dead
-     * connection.
+     * Before the fix, {@code setFTPFile()} set {@code type=DIRECTORY} when {@code getParent()} returned {@code null}, without contacting the server. After the
+     * fix, {@code setFTPFile()} uses CWD to verify, which fails on a dead connection.
      * </p>
      */
     @Test
@@ -77,18 +77,13 @@ public void testRootExistsFailsWhenConnectionDropped() throws Exception {
             manager.addProvider("ftp", new FtpFileProvider());
             manager.init();
             final FileObject root = manager.resolveFile(FtpProviderTest.getConnectionUri(), createOptions());
-
             // Verify precondition: with userDirIsRoot=true, getParent() returns null,
             // which is the code path this test exercises.
-            Assertions.assertNull(root.getParent(),
-                "Root folder's getParent() should return null with userDirIsRoot=true");
-
+            assertNull(root.getParent(), "Root folder's getParent() should return null with userDirIsRoot=true");
             // Verify the root exists initially.
-            Assertions.assertTrue(root.exists(), "Root should exist while server is running");
-
+            assertTrue(root.exists(), "Root should exist while server is running");
             // Stop the server to simulate a connection drop.
             FtpProviderTest.tearDownClass();
-
             // exists() must throw FileSystemException on the dead connection.
             // The first call may still succeed if the MINA server processes one last
             // CWD during graceful shutdown, but the second call must fail.
@@ -101,8 +96,7 @@ public void testRootExistsFailsWhenConnectionDropped() throws Exception {
                     threwException = true;
                 }
             }
-            Assertions.assertTrue(threwException,
-                "exists() must throw FileSystemException after FTP connection is lost");
+            assertTrue(threwException, "exists() must throw FileSystemException after FTP connection is lost");
         }
     }
 }