TemporaryFolder: Migrate to JUnit 5 TempDir API

We use JUnit 4's TemporaryFolder rule to initialise a temporary
folder.

Rules are no longer supported by JUnit 5 test runners. In addition,
JUnit 5.4.0 introduces the TempDir extension that supersedes the
TemporaryFolder rule.

Let's migrate our usage of TemporaryFolder rules to TempDir.

As TempDirs in JUnit 5 are Paths, it is no longer necessary to invoke
methods like getRoot().toPath() on the TempDir. Additionally, the way
to get a URL resource from the TempDir is also different from
TemporaryFolder. The relevant methods have been updated.

In LogicManagerTest and MainWindowCloseTest, the newFile() API is not
supported by JUnit 5's TempDir. However, as the random file name
provided by newFile() is not necessary (we have full control over the
contents of the temporary directory), instead of re-implementing
newFile() to match the behavior of existing tests, we explicitly give
the file names and use Path.resolve() instead.

src/test/java/seedu/address/commons/util/ConfigUtilTest.java

@@ -10,9 +10,8 @@
 import java.util.Optional;
 import java.util.logging.Level;
 
-import org.junit.Rule;
-import org.junit.Test;
-import org.junit.rules.TemporaryFolder;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
 
 import seedu.address.commons.core.Config;
 import seedu.address.commons.exceptions.DataConversionException;
@@ -21,9 +20,8 @@ public class ConfigUtilTest {
 
     private static final Path TEST_DATA_FOLDER = Paths.get("src", "test", "data", "ConfigUtilTest");
 
-
-    @Rule
-    public TemporaryFolder testFolder = new TemporaryFolder();
+    @TempDir
+    public Path tempDir;
 
     @Test
     public void read_null_throwsNullPointerException() {
@@ -89,7 +87,7 @@ public void save_nullFile_throwsNullPointerException() {
     public void saveConfig_allInOrder_success() throws DataConversionException, IOException {
         Config original = getTypicalConfig();
 
-        Path configFilePath = testFolder.getRoot().toPath().resolve("TempConfig.json");
+        Path configFilePath = tempDir.resolve("TempConfig.json");
 
         //Try writing when the file doesn't exist
         ConfigUtil.saveConfig(original, configFilePath);

src/test/java/seedu/address/logic/LogicManagerTest.java

@@ -13,10 +13,9 @@
 import java.io.IOException;
 import java.nio.file.Path;
 
-import org.junit.Before;
-import org.junit.Rule;
-import org.junit.Test;
-import org.junit.rules.TemporaryFolder;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
 
 import seedu.address.logic.commands.AddCommand;
 import seedu.address.logic.commands.CommandResult;
@@ -37,16 +36,17 @@
 public class LogicManagerTest {
     private static final IOException DUMMY_IO_EXCEPTION = new IOException("dummy exception");
 
-    @Rule
-    public TemporaryFolder temporaryFolder = new TemporaryFolder();
+    @TempDir
+    public Path temporaryFolder;
 
     private Model model = new ModelManager();
     private Logic logic;
 
-    @Before
-    public void setUp() throws Exception {
-        JsonAddressBookStorage addressBookStorage = new JsonAddressBookStorage(temporaryFolder.newFile().toPath());
-        JsonUserPrefsStorage userPrefsStorage = new JsonUserPrefsStorage(temporaryFolder.newFile().toPath());
+    @BeforeEach
+    public void setUp() {
+        JsonAddressBookStorage addressBookStorage =
+                new JsonAddressBookStorage(temporaryFolder.resolve("addressBook.json"));
+        JsonUserPrefsStorage userPrefsStorage = new JsonUserPrefsStorage(temporaryFolder.resolve("userPrefs.json"));
         StorageManager storage = new StorageManager(addressBookStorage, userPrefsStorage);
         logic = new LogicManager(model, storage);
     }
@@ -73,11 +73,12 @@ public void execute_validCommand_success() throws Exception {
     }
 
     @Test
-    public void execute_storageThrowsIoException_throwsCommandException() throws Exception {
+    public void execute_storageThrowsIoException_throwsCommandException() {
         // Setup LogicManager with JsonAddressBookIoExceptionThrowingStub
         JsonAddressBookStorage addressBookStorage =
-                new JsonAddressBookIoExceptionThrowingStub(temporaryFolder.newFile().toPath());
-        JsonUserPrefsStorage userPrefsStorage = new JsonUserPrefsStorage(temporaryFolder.newFile().toPath());
+                new JsonAddressBookIoExceptionThrowingStub(temporaryFolder.resolve("ioExceptionAddressBook.json"));
+        JsonUserPrefsStorage userPrefsStorage =
+                new JsonUserPrefsStorage(temporaryFolder.resolve("ioExceptionUserPrefs.json"));
         StorageManager storage = new StorageManager(addressBookStorage, userPrefsStorage);
         logic = new LogicManager(model, storage);
 

src/test/java/seedu/address/storage/JsonAddressBookStorageTest.java

@@ -12,9 +12,8 @@
 import java.nio.file.Path;
 import java.nio.file.Paths;
 
-import org.junit.Rule;
-import org.junit.Test;
-import org.junit.rules.TemporaryFolder;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
 
 import seedu.address.commons.exceptions.DataConversionException;
 import seedu.address.model.AddressBook;
@@ -23,9 +22,8 @@
 public class JsonAddressBookStorageTest {
     private static final Path TEST_DATA_FOLDER = Paths.get("src", "test", "data", "JsonAddressBookStorageTest");
 
-
-    @Rule
-    public TemporaryFolder testFolder = new TemporaryFolder();
+    @TempDir
+    public Path testFolder;
 
     @Test
     public void readAddressBook_nullFilePath_throwsNullPointerException() {
@@ -64,7 +62,7 @@ public void readAddressBook_invalidAndValidPersonAddressBook_throwDataConversion
 
     @Test
     public void readAndSaveAddressBook_allInOrder_success() throws Exception {
-        Path filePath = testFolder.getRoot().toPath().resolve("TempAddressBook.json");
+        Path filePath = testFolder.resolve("TempAddressBook.json");
         AddressBook original = getTypicalAddressBook();
         JsonAddressBookStorage jsonAddressBookStorage = new JsonAddressBookStorage(filePath);
 

src/test/java/seedu/address/storage/JsonUserPrefsStorageTest.java

@@ -9,9 +9,8 @@
 import java.nio.file.Paths;
 import java.util.Optional;
 
-import org.junit.Rule;
-import org.junit.Test;
-import org.junit.rules.TemporaryFolder;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
 
 import seedu.address.commons.core.GuiSettings;
 import seedu.address.commons.exceptions.DataConversionException;
@@ -21,9 +20,8 @@ public class JsonUserPrefsStorageTest {
 
     private static final Path TEST_DATA_FOLDER = Paths.get("src", "test", "data", "JsonUserPrefsStorageTest");
 
-
-    @Rule
-    public TemporaryFolder testFolder = new TemporaryFolder();
+    @TempDir
+    public Path testFolder;
 
     @Test
     public void readUserPrefs_nullFilePath_throwsNullPointerException() {
@@ -107,7 +105,7 @@ public void saveUserPrefs_allInOrder_success() throws DataConversionException, I
         UserPrefs original = new UserPrefs();
         original.setGuiSettings(new GuiSettings(1200, 200, 0, 2));
 
-        Path pefsFilePath = testFolder.getRoot().toPath().resolve("TempPrefs.json");
+        Path pefsFilePath = testFolder.resolve("TempPrefs.json");
         JsonUserPrefsStorage jsonUserPrefsStorage = new JsonUserPrefsStorage(pefsFilePath);
 
         //Try writing when the file doesn't exist

src/test/java/seedu/address/storage/StorageManagerTest.java

@@ -6,10 +6,9 @@
 
 import java.nio.file.Path;
 
-import org.junit.Before;
-import org.junit.Rule;
-import org.junit.Test;
-import org.junit.rules.TemporaryFolder;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
 
 import seedu.address.commons.core.GuiSettings;
 import seedu.address.model.AddressBook;
@@ -18,23 +17,22 @@
 
 public class StorageManagerTest {
 
-    @Rule
-    public TemporaryFolder testFolder = new TemporaryFolder();
+    @TempDir
+    public Path testFolder;
 
     private StorageManager storageManager;
 
-    @Before
+    @BeforeEach
     public void setUp() {
         JsonAddressBookStorage addressBookStorage = new JsonAddressBookStorage(getTempFilePath("ab"));
         JsonUserPrefsStorage userPrefsStorage = new JsonUserPrefsStorage(getTempFilePath("prefs"));
         storageManager = new StorageManager(addressBookStorage, userPrefsStorage);
     }
 
     private Path getTempFilePath(String fileName) {
-        return testFolder.getRoot().toPath().resolve(fileName);
+        return testFolder.resolve(fileName);
     }
 
-
     @Test
     public void prefsReadSave() throws Exception {
         /*

src/test/java/seedu/address/ui/MainWindowCloseTest.java

@@ -3,12 +3,12 @@
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import java.nio.file.Path;
 import java.util.Collections;
 
-import org.junit.Before;
-import org.junit.Rule;
-import org.junit.Test;
-import org.junit.rules.TemporaryFolder;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
 import org.testfx.api.FxToolkit;
 
 import guitests.guihandles.HelpWindowHandle;
@@ -25,17 +25,18 @@
  * Contains tests for closing of the {@code MainWindow}.
  */
 public class MainWindowCloseTest extends GuiUnitTest {
-    @Rule
-    public final TemporaryFolder temporaryFolder = new TemporaryFolder();
+    @TempDir
+    public Path temporaryFolder;
 
     private MainWindow mainWindow;
     private EmptyMainWindowHandle mainWindowHandle;
     private Stage stage;
 
-    @Before
+    @BeforeEach
     public void setUp() throws Exception {
-        JsonAddressBookStorage jsonAddressBookStorage = new JsonAddressBookStorage(temporaryFolder.newFile().toPath());
-        JsonUserPrefsStorage jsonUserPrefsStorage = new JsonUserPrefsStorage(temporaryFolder.newFile().toPath());
+        JsonAddressBookStorage jsonAddressBookStorage =
+                new JsonAddressBookStorage(temporaryFolder.resolve("addressBook.json"));
+        JsonUserPrefsStorage jsonUserPrefsStorage = new JsonUserPrefsStorage(temporaryFolder.resolve("userPrefs.json"));
         StorageManager storageManager = new StorageManager(jsonAddressBookStorage, jsonUserPrefsStorage);
         FxToolkit.setupStage(stage -> {
             this.stage = stage;

src/test/java/seedu/address/ui/UiPartTest.java

@@ -5,10 +5,10 @@
 import static seedu.address.testutil.Assert.assertThrows;
 
 import java.net.URL;
+import java.nio.file.Path;
 
-import org.junit.Rule;
-import org.junit.Test;
-import org.junit.rules.TemporaryFolder;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
 
 import javafx.fxml.FXML;
 import seedu.address.MainApp;
@@ -21,8 +21,8 @@ public class UiPartTest {
     private static final String VALID_FILE_WITH_FX_ROOT_PATH = "UiPartTest/validFileWithFxRoot.fxml";
     private static final TestFxmlObject VALID_FILE_ROOT = new TestFxmlObject("Hello World!");
 
-    @Rule
-    public TemporaryFolder testFolder = new TemporaryFolder();
+    @TempDir
+    public Path testFolder;
 
     @Test
     public void constructor_nullFileUrl_throwsNullPointerException() {
@@ -32,7 +32,7 @@ public void constructor_nullFileUrl_throwsNullPointerException() {
 
     @Test
     public void constructor_missingFileUrl_throwsAssertionError() throws Exception {
-        URL missingFileUrl = new URL(testFolder.getRoot().toURI().toURL(), MISSING_FILE_PATH);
+        URL missingFileUrl = new URL(testFolder.toUri().toURL(), MISSING_FILE_PATH);
         assertThrows(AssertionError.class, () -> new TestUiPart<Object>(missingFileUrl));
         assertThrows(AssertionError.class, () -> new TestUiPart<Object>(missingFileUrl, new Object()));
     }