force US locale for tests

uhabits-core/src/main/java/org/isoron/uhabits/core/utils/DateUtils.java

@@ -34,6 +34,8 @@ public abstract class DateUtils
 
     private static TimeZone fixedTimeZone = null;
 
+    private static Locale fixedLocale = null;
+
     /**
      * Time of the day when the new day starts.
      */
@@ -58,7 +60,7 @@ public abstract class DateUtils
 
     public static String formatHeaderDate(GregorianCalendar day)
     {
-        Locale locale = Locale.getDefault();
+        Locale locale = getLocale();
         String dayOfMonth = Integer.toString(day.get(DAY_OF_MONTH));
         String dayOfWeek = day.getDisplayName(DAY_OF_WEEK, SHORT, locale);
         return dayOfWeek + "\n" + dayOfMonth;
@@ -82,7 +84,7 @@ public abstract class DateUtils
         for (int i = 0; i < wdays.length; i++)
         {
             wdays[i] =
-                day.getDisplayName(DAY_OF_WEEK, format, Locale.getDefault());
+                day.getDisplayName(DAY_OF_WEEK, format, getLocale());
             day.add(DAY_OF_MONTH, 1);
         }
 
@@ -100,7 +102,7 @@ public abstract class DateUtils
 
     /**
      * @return array with weekday names starting according to locale settings,
-     * e.g. [Mo,Di,Mi,Do,Fr,Sa,So] in Europe
+     * e.g. [Mo,Di,Mi,Do,Fr,Sa,So] in Germany
      */
     public static String[] getLocaleDayNames(int format)
     {
@@ -111,7 +113,7 @@ public abstract class DateUtils
         for (int i = 0; i < days.length; i++)
         {
             days[i] = calendar.getDisplayName(DAY_OF_WEEK, format,
-                Locale.getDefault());
+                getLocale());
             calendar.add(DAY_OF_MONTH, 1);
         }
 
@@ -195,6 +197,17 @@ public abstract class DateUtils
         fixedLocalTime = timestamp;
     }
 
+    public static void setFixedLocale(Locale locale)
+    {
+        fixedLocale = locale;
+    }
+
+    private static Locale getLocale()
+    {
+        if(fixedLocale != null) return fixedLocale;
+        return Locale.getDefault();
+    }
+
     public static Long truncate(TruncateField field, long timestamp)
     {
         GregorianCalendar cal = DateUtils.getCalendar(timestamp);

uhabits-core/src/test/java/org/isoron/uhabits/core/utils/DateUtilsTest.java

@@ -31,6 +31,14 @@ import static org.hamcrest.MatcherAssert.*;
 
 public class DateUtilsTest extends BaseUnitTest
 {
+    @Before
+    @Override
+    public void setUp() throws Exception
+    {
+        super.setUp();
+        DateUtils.setFixedLocale(Locale.US);
+    }
+
     @Test
     public void testFormatHeaderDate()
     {