Add configuration parameter for Jimfs default configuration

Closes #1.

README.md

@@ -55,7 +55,7 @@ testImplementation("io.github.scordio:jimfs-junit-jupiter:${jimfsJunitJupiterVer
 
 ### JimfsTempDirFactory
 
-The simplest possible usage is to set the
+The simplest usage is to set the
 [`factory`](https://junit.org/junit5/docs/current/api/org.junit.jupiter.api/org/junit/jupiter/api/io/TempDir.html#factory())
 attribute of `@TempDir` to `JimfsTempDirFactory`:
 
@@ -67,14 +67,13 @@ void test(@TempDir(factory = JimfsTempDirFactory.class) Path tempDir) {
 ```
 
 `tempDir` is resolved into an in-memory temporary directory based on Jimfs, appropriately configured for the current
-operating system.
+platform.
 
 ### @JimfsTempDir
 
 `@JimfsTempDir`, a `@TempDir`
 [composed annotation](https://junit.org/junit5/docs/current/user-guide/#writing-tests-meta-annotations),
-can be used as a drop-in replacement for
-`@TempDir(factory = JimfsTempDirFactory.class)`:
+can be used as a drop-in replacement for `@TempDir(factory = JimfsTempDirFactory.class)`:
 
 ```java
 @Test
@@ -85,16 +84,17 @@ void test(@JimfsTempDir Path tempDir) {
 
 The default behavior of the annotation is equivalent to using `JimfsTempDirFactory` directly:
 `tempDir` is resolved into an in-memory temporary directory based on Jimfs, appropriately configured for the current
-operating system.
+platform.
 
-For better control over the underlying in-memory file system,
-`@JimfsTempDir` offers an optional `value` attribute that can be set to the desired configuration, one of:
-* `FOR_CURRENT_PLATFORM`: appropriate to the current operating system (default)
+For better control over the underlying in-memory file system, `@JimfsTempDir` offers an optional `value` attribute
+that can be set to the desired configuration, one of:
+* `DEFAULT`: based on the corresponding [configuration parameter](#default-jimfs-configuration) (default)
+* `FOR_CURRENT_PLATFORM`: appropriate to the current platform
 * `OS_X`: for a Mac OS X-like file system
 * `UNIX`: for a UNIX-like file system
 * `WINDOWS`: for a Windows-like file system
 
-For example, the following defines a Windows-like temporary directory regardless of the operating system the test
+For example, the following defines a Windows-like temporary directory regardless of the platform the test
 is running on:
 
 ```java
@@ -104,11 +104,16 @@ void test(@JimfsTempDir(WINDOWS) Path tempDir) {
 }
 ```
 
-### Default Configuration
+### Configuration Parameters
+
+Jimfs JUnit Jupiter supports JUnit
+[configuration parameters](https://junit.org/junit5/docs/current/user-guide/#running-tests-config-params).
+
+#### Default `@TempDir` Factory
+
+The `junit.jupiter.tempdir.factory.default` configuration parameter sets the default factory to use, expecting its
+fully qualified class name.
 
-The `junit.jupiter.tempdir.factory.default`
-[configuration parameter](https://junit.org/junit5/docs/current/user-guide/#running-tests-config-params)
-can be used to specify the fully qualified class name of the factory to be used by default.
 For example, the following configures `JimfsTempDirFactory`:
 
 ```properties
@@ -118,6 +123,25 @@ junit.jupiter.tempdir.factory.default=io.github.scordio.jimfs.junit.jupiter.Jimf
 The factory will be used for all `@TempDir` annotations unless the `factory` attribute of the annotation
 specifies a different type.
 
+#### Default Jimfs Configuration
+
+The `jimfs.junit.jupiter.tempdir.configuration.default` configuration parameter sets the default Jimfs configuration
+to use, expecting one of the following (case-insensitive):
+* `FOR_CURRENT_PLATFORM`: appropriate to the current platform (default)
+* `OS_X`: for a Mac OS X-like file system
+* `UNIX`: for a UNIX-like file system
+* `WINDOWS`: for a Windows-like file system
+
+For example, the following defines a Windows-like temporary directory regardless of the platform the test
+is running on:
+
+```properties
+jimfs.junit.jupiter.tempdir.configuration.default=windows
+```
+
+All Jimfs-based temporary directories will be configured accordingly unless `@JimfsTempDir` is used and
+its `value` attribute is set.
+
 ### Limitations
 
 Jimfs JUnit Jupiter only supports annotated fields or parameters of type `Path`, as Jimfs is a non-default file

pom.xml

@@ -73,7 +73,7 @@
     </dependency>
     <dependency>
       <groupId>org.junit.jupiter</groupId>
-      <artifactId>junit-jupiter-engine</artifactId>
+      <artifactId>junit-jupiter</artifactId>
       <scope>test</scope>
     </dependency>
     <dependency>

src/main/java/io/github/scordio/jimfs/junit/jupiter/JimfsTempDir.java

@@ -40,14 +40,25 @@
 @TempDir(factory = JimfsTempDirFactory.class)
 public @interface JimfsTempDir {
 
+  /**
+   * Configuration parameter to set the default {@link Configuration Configuration} for the
+   * in-memory file system.
+   *
+   * <p>If this configuration parameter is not set, the default is {@link
+   * Configuration#FOR_CURRENT_PLATFORM}.
+   *
+   * @since 0.2.0
+   */
+  String DEFAULT_CONFIGURATION_PARAMETER_NAME = "jimfs.junit.jupiter.tempdir.configuration.default";
+
   /**
    * Configuration for the in-memory file system.
    *
    * <p>Defaults to {@link Configuration#FOR_CURRENT_PLATFORM}.
    *
    * @return the configuration to use for the in-memory file system
    */
-  Configuration value() default Configuration.FOR_CURRENT_PLATFORM;
+  Configuration value() default Configuration.DEFAULT;
 
   /**
    * Enumeration of configurations for the in-memory file system.
@@ -56,7 +67,14 @@
    */
   enum Configuration {
     /**
-     * Configuration appropriate to the current operating system.
+     * Default configuration.
+     *
+     * @see #DEFAULT_CONFIGURATION_PARAMETER_NAME
+     * @since 0.2.0
+     */
+    DEFAULT(com.google.common.jimfs.Configuration::forCurrentPlatform),
+    /**
+     * Configuration appropriate to the current platform.
      *
      * @see com.google.common.jimfs.Configuration#forCurrentPlatform()
      */

src/main/java/io/github/scordio/jimfs/junit/jupiter/JimfsTempDirFactory.java

@@ -21,7 +21,9 @@
 import java.nio.file.FileSystem;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.util.Locale;
 import java.util.Optional;
+import java.util.function.Function;
 import java.util.function.Supplier;
 import org.junit.jupiter.api.extension.AnnotatedElementContext;
 import org.junit.jupiter.api.extension.ExtensionContext;
@@ -31,28 +33,33 @@
  * {@link TempDirFactory} implementation that creates an in-memory temporary directory via {@link
  * Jimfs}, using {@value DEFAULT_PREFIX} as the name prefix.
  *
- * <p>If used as a standalone factory within the {@link org.junit.jupiter.api.io.TempDir}
- * annotation, or set as value for the {@value DEFAULT_FACTORY_PROPERTY_NAME} configuration
- * property, the factory configures the underlying file system {@link
- * Configuration#forCurrentPlatform() appropriately for the current operating system}.
+ * <p>When used as a standalone factory within the {@link org.junit.jupiter.api.io.TempDir}
+ * annotation, or set as value for the {@value
+ * org.junit.jupiter.api.io.TempDir#DEFAULT_FACTORY_PROPERTY_NAME} configuration parameter, the
+ * factory configures the underlying file system appropriately for the {@link
+ * com.google.common.jimfs.Configuration#forCurrentPlatform() current platform}.
  *
- * <p>For better control over the underlying in-memory file system, consider using the {@link
- * JimfsTempDir} composed annotation and its {@link JimfsTempDir#value() value} attribute.
+ * <p>For better control over the underlying in-memory file system, consider using one of the
+ * following options:
+ *
+ * <ul>
+ *   <li>The {@link JimfsTempDir} composed annotation and its {@link JimfsTempDir#value() value}
+ *       attribute.
+ *   <li>The {@value JimfsTempDir#DEFAULT_CONFIGURATION_PARAMETER_NAME} configuration parameter.
+ * </ul>
  *
  * <p>Please note that only annotated fields or parameters of type {@link java.nio.file.Path} are
  * supported as Jimfs is a non-default file system, and {@link java.io.File} instances are
  * associated with the default file system only.
  *
- * @see Jimfs#newFileSystem(Configuration)
- * @see Configuration#forCurrentPlatform()
+ * @see Jimfs#newFileSystem(com.google.common.jimfs.Configuration)
+ * @see com.google.common.jimfs.Configuration#forCurrentPlatform()
  */
 public final class JimfsTempDirFactory implements TempDirFactory {
 
   private static final String DEFAULT_PREFIX = "junit-";
-
-  @SuppressWarnings("unused")
-  private static final String DEFAULT_FACTORY_PROPERTY_NAME =
-      org.junit.jupiter.api.io.TempDir.DEFAULT_FACTORY_PROPERTY_NAME;
+  private static final Function<String, JimfsTempDir.Configuration> CONFIGURATION_TRANSFORMER =
+      value -> JimfsTempDir.Configuration.valueOf(value.trim().toUpperCase(Locale.ROOT));
 
   private FileSystem fileSystem;
 
@@ -69,14 +76,27 @@ public Path createTempDirectory(
     Supplier<Configuration> configuration =
         annotation
             .map(JimfsTempDir::value)
+            .filter(JimfsTempDirFactory::isNotDefaultConfiguration)
             .map(JimfsTempDir.Configuration::getConfiguration)
-            .orElse(Configuration::forCurrentPlatform);
+            .orElseGet(
+                () ->
+                    extensionContext
+                        .getConfigurationParameter(
+                            JimfsTempDir.DEFAULT_CONFIGURATION_PARAMETER_NAME,
+                            CONFIGURATION_TRANSFORMER)
+                        .filter(JimfsTempDirFactory::isNotDefaultConfiguration)
+                        .map(JimfsTempDir.Configuration::getConfiguration)
+                        .orElse(Configuration::forCurrentPlatform));
 
     fileSystem = Jimfs.newFileSystem(configuration.get());
     Path root = fileSystem.getRootDirectories().iterator().next();
     return Files.createTempDirectory(root, DEFAULT_PREFIX);
   }
 
+  private static boolean isNotDefaultConfiguration(JimfsTempDir.Configuration value) {
+    return value != JimfsTempDir.Configuration.DEFAULT;
+  }
+
   /** {@inheritDoc} */
   @Override
   public void close() throws IOException {