chore/test: add LocaleRule fixture

src/org/omegat/util/OStrings.java

@@ -28,6 +28,7 @@
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.IOException;
+import java.util.Locale;
 import java.util.PropertyResourceBundle;
 import java.util.ResourceBundle;
 import java.util.function.Function;
@@ -71,8 +72,10 @@ private OStrings() {
         IS_BETA = !b.getString("beta").isEmpty();
     }
 
+    private static final String BASENAME = "org/omegat/Bundle";
+
     /** Resource bundle that contains all the strings */
-    private static ResourceBundle bundle = ResourceBundle.getBundle("org/omegat/Bundle");
+    private static ResourceBundle bundle = ResourceBundle.getBundle(BASENAME);
 
     /**
      * Returns resource bundle.
@@ -81,6 +84,14 @@ public static ResourceBundle getResourceBundle() {
         return bundle;
     }
 
+    /**
+     * Loads resources with the specified locale.
+     * @param locale Locale to load.
+     */
+    public static void loadBundle(Locale locale) {
+        bundle = ResourceBundle.getBundle(BASENAME, locale);
+    }
+
     /**
      * Loads resources from the specified file. If the file cannot be loaded,
      * resources are reverted to the default locale. Useful when testing

test/fixtures/org/omegat/util/LocaleRule.java

@@ -0,0 +1,59 @@
+/**************************************************************************
+ OmegaT - Computer Assisted Translation (CAT) tool
+          with fuzzy matching, translation memory, keyword search,
+          glossaries, and translation leveraging into updated projects.
+
+ Copyright (C) 2024 Hiroshi Miura
+               Home page: https://www.omegat.org/
+               Support center: https://omegat.org/support
+
+ This file is part of OmegaT.
+
+ OmegaT is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ OmegaT is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ **************************************************************************/
+
+package org.omegat.util;
+
+import java.util.Locale;
+
+import org.junit.rules.TestRule;
+import org.junit.runner.Description;
+import org.junit.runners.model.Statement;
+
+public class LocaleRule implements TestRule {
+    private final Locale testLocale;
+    private Locale originalLocale;
+
+    public LocaleRule(Locale locale) {
+        this.testLocale = locale;
+    }
+
+    @Override
+    public Statement apply(Statement base, Description description) {
+        return new Statement() {
+            @Override
+            public void evaluate() throws Throwable {
+                originalLocale = Locale.getDefault();
+                Locale.setDefault(testLocale);
+                OStrings.loadBundle(testLocale);
+                try {
+                    base.evaluate();
+                } finally {
+                    Locale.setDefault(originalLocale);
+                    OStrings.loadBundle(originalLocale);
+                }
+            }
+        };
+    }
+}