LANG-1127: Use JUnit rules to set and reset the default Locale and TimeZone.

src/test/java/org/apache/commons/lang3/StringUtilsEqualsIndexOfTest.java

@@ -23,8 +23,9 @@ import static org.junit.Assert.assertTrue;
 
 import java.util.Locale;
 
-import org.apache.commons.lang3.test.DefaultLocale;
+import org.apache.commons.lang3.time.TestLocale;
 import org.hamcrest.core.IsNot;
+import org.junit.Rule;
 import org.junit.Test;
 
 /**
@@ -33,6 +34,10 @@ import org.junit.Test;
  * @version $Id$
  */
 public class StringUtilsEqualsIndexOfTest  {
+
+    @Rule
+    public TestLocale locale = TestLocale.usingDefaultLocale();
+
     private static final String BAR = "bar";
     /**
      * Supplementary character U+20000
@@ -246,11 +251,8 @@ public class StringUtilsEqualsIndexOfTest  {
             { "\u00DF", "SS" },
         };
 
-        new DefaultLocale<RuntimeException>(Locale.ENGLISH) {
+        for (final Locale testLocale : locales) {
-            @Override
+            locale.setLocale(testLocale);
-            public void test() {
-                for (final Locale locale : locales) {
-                    Locale.setDefault(locale);
             for (int j = 0; j < tdata.length; j++) {
                 assertTrue(Locale.getDefault() + ": " + j + " " + tdata[j][0] + " " + tdata[j][1], StringUtils
                         .containsIgnoreCase(tdata[j][0], tdata[j][1]));
@@ -261,8 +263,6 @@ public class StringUtilsEqualsIndexOfTest  {
             }
         }
     }
-        };
-    }
 
     @Test
     public void testContainsIgnoreCase_StringString() {

src/test/java/org/apache/commons/lang3/test/DefaultLocale.java

@@ -1,43 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.apache.commons.lang3.test;
-
-import java.util.Locale;
-
-/**
- * run a test with a different default Locale
- */
-public abstract class DefaultLocale<E extends Throwable> {
-
-    public DefaultLocale(Locale targetLocale) throws E {
-        // only one test at a time may change default
-        synchronized (getClass()) {
-            Locale defaultLocale = Locale.getDefault();
-            try {
-                Locale.setDefault(targetLocale);
-                test();
-            } finally {
-                Locale.setDefault(defaultLocale);
-            }
-        }
-    }
-
-    /**
-     * Implement test in this method
-     */
-    abstract public void test() throws E;
-}

src/test/java/org/apache/commons/lang3/test/DefaultTimeZone.java

@@ -1,43 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.apache.commons.lang3.test;
-
-import java.util.TimeZone;
-
-/**
- * run a test with a different default TimeZone
- */
-public abstract class DefaultTimeZone<E extends Throwable> {
-
-    public DefaultTimeZone(TimeZone targetZone) throws E {
-        // only one test at a time may change default
-        synchronized (getClass()) {
-            TimeZone defaultZone = TimeZone.getDefault();
-            try {
-                TimeZone.setDefault(targetZone);
-                test();
-            } finally {
-                TimeZone.setDefault(defaultZone);
-            }
-        }
-    }
-
-    /**
-     * Implement test in this method
-     */
-    abstract public void test() throws E;
-}

src/test/java/org/apache/commons/lang3/test/DefaultTimeZoneAndLocale.java

@@ -1,45 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.apache.commons.lang3.test;
-
-import java.util.Locale;
-import java.util.TimeZone;
-
-/**
- * run a test with a different default TimeZone and Locale
- */
-public abstract class DefaultTimeZoneAndLocale<E extends Throwable> {
-
-    public DefaultTimeZoneAndLocale(TimeZone targetZone, final Locale targetLocale) throws E {
-        new DefaultTimeZone<E>(targetZone) {
-            @Override
-            public void test() throws E {
-                new DefaultLocale<E>(targetLocale) {
-                    @Override
-                    public void test() throws E {
-                        DefaultTimeZoneAndLocale.this.test();
-                    }
-                };
-            }
-        };
-    }
-
-    /**
-     * Implement test in this method
-     */
-    abstract public void test() throws E;
-}

src/test/java/org/apache/commons/lang3/time/DateFormatUtilsTest.java

@@ -29,8 +29,7 @@ import java.util.Date;
 import java.util.Locale;
 import java.util.TimeZone;
 
-import org.apache.commons.lang3.test.DefaultLocale;
+import org.junit.Rule;
-import org.apache.commons.lang3.test.DefaultTimeZone;
 import org.junit.Test;
 
 /**
@@ -39,6 +38,11 @@ import org.junit.Test;
  */
 public class DateFormatUtilsTest {
 
+    @Rule
+    public TestTimeZone timeZone = TestTimeZone.usingDefaultTimeZone();
+    @Rule 
+    public TestLocale locale = TestLocale.usingDefaultLocale();
+    
     //-----------------------------------------------------------------------
     @Test
     public void testConstructor() {
@@ -169,9 +173,8 @@ public class DateFormatUtilsTest {
 
     @Test
     public void testSMTP() {
-        new DefaultLocale<RuntimeException>(Locale.ENGLISH) {
+        locale.setLocale(Locale.ENGLISH);
-            @Override
+
-            public void test() {
         TimeZone timeZone = TimeZone.getTimeZone("GMT-3");
         Calendar june = createJuneTestDate(timeZone);
 
@@ -183,8 +186,6 @@ public class DateFormatUtilsTest {
         assertFormats("Sun, 08 Jun 2003 10:11:12 +0000", DateFormatUtils.SMTP_DATETIME_FORMAT.getPattern(),
                 timeZone, june);
     }
-        };
-    }
 
     /*
     public void testLang312() {
@@ -222,17 +223,14 @@ public class DateFormatUtilsTest {
 
     @Test
     public void testLang530() throws ParseException {
-        new DefaultTimeZone<ParseException>(TimeZone.getTimeZone("UTC")) {
+        timeZone.setTimeZone("UTC");
-            @Override
+
-            public void test() throws ParseException {
         final Date d = new Date();
         final String isoDateStr = DateFormatUtils.ISO_DATETIME_TIME_ZONE_FORMAT.format(d);
         final Date d2 = DateUtils.parseDate(isoDateStr, new String[] { DateFormatUtils.ISO_DATETIME_TIME_ZONE_FORMAT.getPattern() });
         // the format loses milliseconds so have to reintroduce them
         assertEquals("Date not equal to itself ISO formatted and parsed", d.getTime(), d2.getTime() + d.getTime() % 1000);
     }
-        };
-    }
 
     /**
      * According to LANG-916 (https://issues.apache.org/jira/browse/LANG-916),

src/test/java/org/apache/commons/lang3/time/DateUtilsTest.java

@@ -37,10 +37,9 @@ import java.util.NoSuchElementException;
 import java.util.TimeZone;
 
 import junit.framework.AssertionFailedError;
-
-import org.apache.commons.lang3.test.DefaultLocale;
 import org.junit.Before;
 import org.junit.BeforeClass;
+import org.junit.Rule;
 import org.junit.Test;
 
 /**
@@ -58,6 +57,9 @@ public class DateUtilsTest {
         BASE_DATE = cal.getTime();
     }
 
+    @Rule
+    public TestLocale locale = TestLocale.usingDefaultLocale();
+    
     private DateFormat dateParser = null;
     private DateFormat dateTimeParser = null;
     private Date dateAmPm1 = null;
@@ -1563,58 +1565,43 @@ public class DateUtilsTest {
 
     @Test
     public void testLANG799_EN_OK() throws ParseException {
-        new DefaultLocale<ParseException>(Locale.ENGLISH){
+        locale.setLocale(Locale.ENGLISH);
-            @Override
+
-            public void test() throws ParseException {
         DateUtils.parseDate("Wed, 09 Apr 2008 23:55:38 GMT", "EEE, dd MMM yyyy HH:mm:ss zzz");
         DateUtils.parseDateStrictly("Wed, 09 Apr 2008 23:55:38 GMT", "EEE, dd MMM yyyy HH:mm:ss zzz");
     }
-        };
-    }
 
     // Parse German date with English Locale
     @Test(expected = ParseException.class)
     public void testLANG799_EN_FAIL() throws ParseException {
-        new DefaultLocale<ParseException>(Locale.ENGLISH){
+        locale.setLocale(Locale.ENGLISH);
-            @Override
+
-            public void test() throws ParseException {
         DateUtils.parseDate("Mi, 09 Apr 2008 23:55:38 GMT", "EEE, dd MMM yyyy HH:mm:ss zzz");
     }
-        };
-    }
 
     @Test
     public void testLANG799_DE_OK() throws ParseException {
-        new DefaultLocale<ParseException>(Locale.GERMAN){
+        locale.setLocale(Locale.GERMAN);
-            @Override
+
-            public void test() throws ParseException {
         DateUtils.parseDate("Mi, 09 Apr 2008 23:55:38 GMT", "EEE, dd MMM yyyy HH:mm:ss zzz");
         DateUtils.parseDateStrictly("Mi, 09 Apr 2008 23:55:38 GMT", "EEE, dd MMM yyyy HH:mm:ss zzz");
     }
-        };
-    }
 
     // Parse English date with German Locale
     @Test(expected=ParseException.class)
     public void testLANG799_DE_FAIL() throws ParseException {
-        new DefaultLocale<ParseException>(Locale.GERMAN){
+        locale.setLocale(Locale.GERMAN);
-            @Override
+
-            public void test() throws ParseException {
         DateUtils.parseDate("Wed, 09 Apr 2008 23:55:38 GMT", "EEE, dd MMM yyyy HH:mm:ss zzz");
     }
-        };
-    }
     
     // Parse German date with English Locale, specifying German Locale override
     @Test
     public void testLANG799_EN_WITH_DE_LOCALE() throws ParseException {
-        new DefaultLocale<ParseException>(Locale.ENGLISH){
+        locale.setLocale(Locale.ENGLISH);
-            @Override
+
-            public void test() throws ParseException {
         DateUtils.parseDate("Mi, 09 Apr 2008 23:55:38 GMT", Locale.GERMAN, "EEE, dd MMM yyyy HH:mm:ss zzz");
     }
-        };
-    }
     
     /**
      * This checks that this is a 7 element iterator of Calendar objects

src/test/java/org/apache/commons/lang3/time/FastDateFormatTest.java

@@ -18,6 +18,7 @@ package org.apache.commons.lang3.time;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotSame;
 import static org.junit.Assert.assertSame;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
@@ -34,8 +35,7 @@ import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicLong;
 
-import org.apache.commons.lang3.test.DefaultLocale;
+import org.junit.Rule;
-import org.apache.commons.lang3.test.DefaultTimeZoneAndLocale;
 import org.junit.Test;
 
 /**
@@ -46,6 +46,12 @@ import org.junit.Test;
  */
 public class FastDateFormatTest {
 
+    @Rule
+    public TestLocale locale = TestLocale.usingDefaultLocale();
+
+    @Rule
+    public TestTimeZone timeZone = TestTimeZone.usingDefaultTimeZone();
+
     /*
      * Only the cache methods need to be tested here.  
      * The print methods are tested by {@link FastDateFormat_PrinterTest}
@@ -73,9 +79,9 @@ public class FastDateFormatTest {
 
     @Test
     public void test_getInstance_String_TimeZone() {
-        new DefaultTimeZoneAndLocale<RuntimeException>(TimeZone.getTimeZone("America/New_York"), Locale.US) {
+        locale.setLocale(Locale.US);
-            @Override
+        timeZone.setTimeZone("America/New_York");
-            public void test() {
+
         final FastDateFormat format1 = FastDateFormat.getInstance("MM/DD/yyyy",
                 TimeZone.getTimeZone("Atlantic/Reykjavik"));
         final FastDateFormat format2 = FastDateFormat.getInstance("MM/DD/yyyy");
@@ -84,37 +90,31 @@ public class FastDateFormatTest {
         final FastDateFormat format5 = FastDateFormat.getInstance("MM-DD-yyyy", TimeZone.getDefault());
         final FastDateFormat format6 = FastDateFormat.getInstance("MM-DD-yyyy");
 
-                assertTrue(format1 != format2); // -- junit 3.8 version -- assertFalse(format1 == format2);
+        assertNotSame(format1, format2);
         assertEquals(TimeZone.getTimeZone("Atlantic/Reykjavik"), format1.getTimeZone());
         assertEquals(TimeZone.getDefault(), format2.getTimeZone());
         assertSame(format3, format4);
-                assertTrue(format3 != format5); // -- junit 3.8 version -- assertFalse(format3 == format5);
+        assertNotSame(format3, format5);
-                assertTrue(format4 != format6); // -- junit 3.8 version -- assertFalse(format3 == format5);
+        assertNotSame(format4, format6);
-            }
-        };
     }
 
     @Test
     public void test_getInstance_String_Locale() {
-        new DefaultLocale<RuntimeException>(Locale.US) {
+        locale.setLocale(Locale.US);
-            @Override
+
-            public void test() throws RuntimeException {
         final FastDateFormat format1 = FastDateFormat.getInstance("MM/DD/yyyy", Locale.GERMANY);
         final FastDateFormat format2 = FastDateFormat.getInstance("MM/DD/yyyy");
         final FastDateFormat format3 = FastDateFormat.getInstance("MM/DD/yyyy", Locale.GERMANY);
 
-                assertTrue(format1 != format2); // -- junit 3.8 version -- assertFalse(format1 == format2);
+        assertNotSame(format1, format2);
         assertSame(format1, format3);
         assertEquals(Locale.GERMANY, format1.getLocale());
     }
-        };
-    }
 
     @Test
     public void test_changeDefault_Locale_DateInstance() {
-        new DefaultLocale<RuntimeException>(Locale.US) {
+        locale.setLocale(Locale.US);
-            @Override
+
-            public void test() throws RuntimeException {
         final FastDateFormat format1 = FastDateFormat.getDateInstance(FastDateFormat.FULL, Locale.GERMANY);
         final FastDateFormat format2 = FastDateFormat.getDateInstance(FastDateFormat.FULL);
         Locale.setDefault(Locale.GERMANY);
@@ -123,17 +123,14 @@ public class FastDateFormatTest {
         assertSame(Locale.GERMANY, format1.getLocale());
         assertSame(Locale.US, format2.getLocale());
         assertSame(Locale.GERMANY, format3.getLocale());
-                assertTrue(format1 != format2); // -- junit 3.8 version -- assertFalse(format1 == format2);
+        assertNotSame(format1, format2);
-                assertTrue(format2 != format3);
+        assertNotSame(format2, format3);
-            }
-        };
     }
 
     @Test
     public void test_changeDefault_Locale_DateTimeInstance() {
-        new DefaultLocale<RuntimeException>(Locale.US) {
+        locale.setLocale(Locale.US);
-            @Override
+
-            public void test() throws RuntimeException {
         final FastDateFormat format1 = FastDateFormat.getDateTimeInstance(FastDateFormat.FULL, FastDateFormat.FULL, Locale.GERMANY);
         final FastDateFormat format2 = FastDateFormat.getDateTimeInstance(FastDateFormat.FULL, FastDateFormat.FULL);
         Locale.setDefault(Locale.GERMANY);
@@ -142,24 +139,22 @@ public class FastDateFormatTest {
         assertSame(Locale.GERMANY, format1.getLocale());
         assertSame(Locale.US, format2.getLocale());
         assertSame(Locale.GERMANY, format3.getLocale());
-                assertTrue(format1 != format2); // -- junit 3.8 version -- assertFalse(format1 == format2);
+        assertNotSame(format1, format2);
-                assertTrue(format2 != format3);
+        assertNotSame(format2, format3);
-            }
-        };
     }
 
     @Test
     public void test_getInstance_String_TimeZone_Locale() {
-        new DefaultTimeZoneAndLocale<RuntimeException>(TimeZone.getTimeZone("America/New_York"), Locale.US) {
+        locale.setLocale(Locale.US);
-            @Override
+        timeZone.setTimeZone("America/New_York");
-            public void test() {
+
         final FastDateFormat format1 = FastDateFormat.getInstance("MM/DD/yyyy",
                 TimeZone.getTimeZone("Atlantic/Reykjavik"), Locale.GERMANY);
         final FastDateFormat format2 = FastDateFormat.getInstance("MM/DD/yyyy", Locale.GERMANY);
         final FastDateFormat format3 = FastDateFormat.getInstance("MM/DD/yyyy",
                 TimeZone.getDefault(), Locale.GERMANY);
 
-                assertTrue(format1 != format2); // -- junit 3.8 version -- assertNotSame(format1, format2);
+        assertNotSame(format1, format2);
         assertEquals(TimeZone.getTimeZone("Atlantic/Reykjavik"), format1.getTimeZone());
         assertEquals(TimeZone.getDefault(), format2.getTimeZone());
         assertEquals(TimeZone.getDefault(), format3.getTimeZone());
@@ -167,8 +162,6 @@ public class FastDateFormatTest {
         assertEquals(Locale.GERMANY, format2.getLocale());
         assertEquals(Locale.GERMANY, format3.getLocale());
     }
-        };
-    }       
 
     @Test
     public void testCheckDefaults() {

src/test/java/org/apache/commons/lang3/time/FastDatePrinterTest.java

@@ -30,7 +30,9 @@ import java.util.Locale;
 import java.util.TimeZone;
 
 import org.apache.commons.lang3.SerializationUtils;
-import org.apache.commons.lang3.test.DefaultTimeZoneAndLocale;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Rule;
 import org.junit.Test;
 
 /**
@@ -74,11 +76,16 @@ public class FastDatePrinterTest {
         return new FastDatePrinter(format, timeZone, locale);
     }
 
+    @Rule
+    public TestLocale locale = TestLocale.usingDefaultLocale();
+
+    @Rule
+    public TestTimeZone timeZone = TestTimeZone.usingDefaultTimeZone();
+
     @Test
     public void testFormat() {
-        new DefaultTimeZoneAndLocale<RuntimeException>(NEW_YORK, Locale.US) {
+        locale.setLocale(Locale.US);
-            @Override
+        timeZone.setTimeZone(NEW_YORK);
-            public void test() {
 
         final GregorianCalendar cal1 = new GregorianCalendar(2003, 0, 10, 15, 33, 20);
         final GregorianCalendar cal2 = new GregorianCalendar(2003, 6, 10, 9, 0, 0);
@@ -123,8 +130,6 @@ public class FastDatePrinterTest {
         assertEquals(sdf.format(date1).replaceAll("2003 03 03 03", "2003 2003 03 2003"), fdf.format(date1));
         assertEquals(sdf.format(date2).replaceAll("2003 03 03 03", "2003 2003 03 2003"), fdf.format(date2));
     }
-        };
-    }
 
     /**
      * Test case for {@link FastDateParser#FastDateParser(String, TimeZone, Locale)}.
@@ -264,6 +269,8 @@ public class FastDatePrinterTest {
 
     @Test
     public void testTimeZoneAsZ() throws Exception {
+        timeZone.setTimeZone("UTC");
+
         Calendar c = Calendar.getInstance(TimeZone.getTimeZone("UTC"));
         FastDateFormat noColonFormat = FastDateFormat.getInstance("Z");
         assertEquals("+0000", noColonFormat.format(c));

src/test/java/org/apache/commons/lang3/time/TestLocale.java

@@ -0,0 +1,136 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ * 
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.commons.lang3.time;
+
+import java.util.Locale;
+
+import org.junit.rules.TestRule;
+import org.junit.runner.Description;
+import org.junit.runners.model.Statement;
+
+/**
+ * Rule implementation that sets and resets the default Locale.
+ * 
+ * <p>
+ * Set up tests to use {@code Locale.getDefault()} by creating a TestLocale rule using {@link #usingDefaultLocale()}.
+ * To override the default Locale for a single test method, use {@link #setLocale(Locale)}. The TestLocale rule will
+ * make sure, that the default Locale is restored after each test.
+ * </p>
+ * 
+ * <pre>
+ * public class LocaleDependentTest {
+ *
+ *     {@literal@}Rule
+ *     public TestLocale locale = TestLocale.usingDefaultLocale();
+ *
+ *     {@literal@}Test
+ *     public void testThatWillExecuteWithTheDefaultLocale() {
+ *         // nothing to do, just implement the test
+ *     }
+ *
+ *     {@literal@}Test
+ *     public void testWithDifferentDefaultLocale() {
+ *         locale.setLocale(Locale.CHINA);
+ *         // Locale.getDefault() will return Locale.CHINA until the end of this test method
+ *     }
+ * }
+ * </pre>
+ * 
+ * <p>
+ * If all tests should use a different default Locale, use {@link #using(Locale)}. All tests will then have the given
+ * Locale set as default Locale. After each test method, the default Locale is restored to its initial value.
+ * </p>
+ * 
+ * <pre>
+ * public class LocaleDependentTest {
+ *
+ *     {@literal@}Rule
+ *     public TestLocale locale = TestLocale.using(Locale.CHINA);
+ *
+ *     {@literal@}Test
+ *     public void testThatWillExecuteWithLocaleChina() {
+ *         // nothing to do, just implement the test
+ *     }
+ *
+ *     {@literal@}Test
+ *     public void testWithDifferentDefaultLocale() {
+ *         locale.setLocale(Locale.US);
+ *         // Locale.getDefault() will return Locale.US until the end of this test method
+ *     }
+ * }
+ * </pre>
+ *
+ * @see TestTimeZone
+ */
+public class TestLocale implements TestRule {
+
+    private static final Locale DEFAULT_LOCALE = Locale.getDefault();
+
+    /**
+     * Creates a new instance using the default locale as default for tests.
+     *
+     * <p>
+     * The locale used for tests can be overridden using {@link #setLocale(Locale)}.
+     * </p>
+     */
+    public static TestLocale usingDefaultLocale() {
+        return new TestLocale(DEFAULT_LOCALE);
+    }
+
+    /**
+     * Creates a new instance using the provided locale as default for tests.
+     *
+     * <p>
+     * The locale used for tests can be overridden using {@link #setLocale(Locale)}.
+     * </p>
+     *
+     * @param testLocale the locale to run tests with.
+     */
+    public static TestLocale using(final Locale testLocale) {
+        return new TestLocale(testLocale);
+    }
+
+    private Locale testLocale;
+
+    private TestLocale(final Locale testLocale) {
+        this.testLocale = testLocale;
+    }
+
+    /**
+     * Override the configured test locale for this test execution.
+     *
+     * @param testLocale the locale to run this test with.
+     */
+    public void setLocale(final Locale testLocale) {
+        Locale.setDefault(testLocale);
+    }
+
+    @Override
+    public Statement apply(final Statement base, final Description description) {
+        return new Statement() {
+            @Override
+            public void evaluate() throws Throwable {
+                Locale.setDefault(testLocale);
+                try {
+                    base.evaluate();
+                } finally {
+                    Locale.setDefault(DEFAULT_LOCALE);
+                }
+            }
+        };
+    }
+}

src/test/java/org/apache/commons/lang3/time/TestTimeZone.java

@@ -0,0 +1,163 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ * 
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.commons.lang3.time;
+
+import java.util.TimeZone;
+
+import org.junit.rules.TestRule;
+import org.junit.runner.Description;
+import org.junit.runners.model.Statement;
+
+/**
+ * Rule implementation that sets and resets the default TimeZone.
+ * 
+ * <p>
+ * Set up tests to use {@code TimeZone.getDefault()} by creating a TestTimeZone rule using {@link #usingDefaultTimeZone()}.
+ * To override the default TimeZone for a single test method, use {@link #setTimeZone(TimeZone)} or
+ * {@link #setTimeZone(String)}. The TestTimeZone rule will make sure, that the default TimeZone is restored after each
+ * test.
+ * </p>
+ * 
+ * <pre>
+ * public class TimeZoneDependentTest {
+ *
+ *     {@literal@}Rule
+ *     public TestTimeZone timeZone = TestTimeZone.usingDefaultTimeZone();
+ *
+ *     {@literal@}Test
+ *     public void testThatWillExecuteWithTheDefaultTimeZone() {
+ *         // nothing to do, just implement the test
+ *     }
+ *
+ *     {@literal@}Test
+ *     public void testWithDifferentDefaultTimeZone() {
+ *         timeZone.setTimeZone("UTC");
+ *         // TimeZone.getDefault() will return TimeZone.getTimeZone("UTC") until the end of this test method
+ *     }
+ * }
+ * </pre>
+ * 
+ * <p>
+ * If all tests should use a different default TimeZone, use {@link #using(TimeZone)} or {@link #using(String)}. All
+ * tests will then have the given TimeZone set as default TimeZone. After each test method, the default TimeZone is
+ * restored to its initial value.
+ * </p>
+ * 
+ * <pre>
+ * public class TimeZoneDependentTest {
+ *
+ *     {@literal@}Rule
+ *     public TestTimeZone timeZone = TestTimeZone.using("UTC");
+ *
+ *     {@literal@}Test
+ *     public void testThatWillExecuteWithTimeZoneUTC() {
+ *         // nothing to do, just implement the test
+ *     }
+ *
+ *     {@literal@}Test
+ *     public void testWithDifferentDefaultTimeZone() {
+ *         timeZone.setTimeZone("GMT")
+ *         // TimeZone.getDefault() will return TimeZone.getTimeZone("GMT") until the end of this test method
+ *     }
+ * }
+ * </pre>
+ *
+ * @see TestLocale
+ */
+public class TestTimeZone implements TestRule {
+
+    private static final TimeZone DEFAULT_TIMEZONE = TimeZone.getDefault();
+
+    /**
+     * Creates a new instance using the default TimeZone for tests.
+     *
+     * <p>
+     * The TimeZone used for tests can be overridden with {@link #setTimeZone(String)} and
+     * {@link #setTimeZone(TimeZone)}.
+     * </p>
+     */
+    public static TestTimeZone usingDefaultTimeZone() {
+        return new TestTimeZone(DEFAULT_TIMEZONE);
+    }
+
+    /**
+     * Creates a new instance using the provided TimeZone as default for tests.
+     * 
+     * <p>
+     * The TimeZone used for tests can be overridden with {@link #setTimeZone(String)} and
+     * {@link #setTimeZone(TimeZone)}.
+     * </p>
+     *
+     * @param testTimeZone the TimeZone to run tests with.
+     */
+    public static TestTimeZone using(final TimeZone testTimeZone) {
+        return new TestTimeZone(testTimeZone);
+    }
+
+    /**
+     * Creates a new instance using the provided zone Id to set the default TimeZone for tests.
+     * 
+     * <p>
+     * The TimeZone used for tests can be overridden with {@link #setTimeZone(String)} and
+     * {@link #setTimeZone(TimeZone)}.
+     * </p>
+     *
+     * @param testTimeZoneId the ID of the TimeZone to run tests with.
+     */
+    public static TestTimeZone using(final String testTimeZoneId) {
+        return new TestTimeZone(TimeZone.getTimeZone(testTimeZoneId));
+    }
+
+    private TimeZone testTimeZone;
+
+    private TestTimeZone(final TimeZone testTimeZone) {
+        this.testTimeZone = testTimeZone;
+    }
+
+    /**
+     * Override the configured test locale for this test excution.
+     *
+     * @param testTimeZone the TimeZone to run this test with.
+     */
+    public void setTimeZone(final TimeZone testTimeZone) {
+        TimeZone.setDefault(testTimeZone);
+    }
+
+    /**
+     * Override the configured test locale for this test excution.
+     *
+     * @param zoneId the ID of the TimeZone to run tests with.
+     */
+    public void setTimeZone(final String zoneId) {
+        setTimeZone(TimeZone.getTimeZone(zoneId));
+    }
+
+    @Override
+    public Statement apply(final Statement base, final Description description) {
+        return new Statement() {
+            @Override
+            public void evaluate() throws Throwable {
+                TimeZone.setDefault(testTimeZone);
+                try {
+                    base.evaluate();
+                } finally {
+                    TimeZone.setDefault(DEFAULT_TIMEZONE);
+                }
+            }
+        };
+    }
+}