Fixed clock-change date ranges and blocks displayed at the wrong hour

src/org/uwpr/instrumentlog/UsageBlockBase.java

@@ -188,6 +188,10 @@ public void setSetupBlock(boolean setupBlock) {
 		this.setupBlock = setupBlock;
 	}
 
+	/**
+	 * Returns the elapsed hours from start to end.  Across a daylight saving change this is one hour less or
+	 * more than the clock times.  Billing, the instrument time quota and the scheduled time totals use this count.
+	 */
 	public int getHours()
 	{
 		return TimeUtils.getHours(getStartDate(), getEndDate());

src/org/uwpr/instrumentlog/UsageBlockBaseTest.java

@@ -0,0 +1,65 @@
+package org.uwpr.instrumentlog;
+
+import java.util.Calendar;
+import java.util.Date;
+import java.util.TimeZone;
+
+import junit.framework.TestCase;
+
+/**
+ * getHours() must count elapsed hours.  A block across a daylight saving change counts one hour less or more
+ * than its clock times.
+ */
+public class UsageBlockBaseTest extends TestCase {
+
+    private TimeZone defaultZone;
+
+    protected void setUp() throws Exception {
+        super.setUp();
+        defaultZone = TimeZone.getDefault();
+        TimeZone.setDefault(TimeZone.getTimeZone("America/Los_Angeles"));
+    }
+
+    protected void tearDown() throws Exception {
+        TimeZone.setDefault(defaultZone);
+        super.tearDown();
+    }
+
+    public final void testHoursWithNoClockChange() {
+        UsageBlockBase block = block(2026, 9, 16, 22, 2026, 9, 17, 6);
+        assertEquals("10 PM to 6 AM with no clock change should be 8 hours", 8, block.getHours());
+    }
+
+    public final void testHoursAcrossSpringForward() {
+        // Clocks go from 2 AM to 3 AM on 2026-03-08.
+        UsageBlockBase block = block(2026, 3, 7, 22, 2026, 3, 8, 6);
+        assertEquals("10 PM to 6 AM across spring forward should be 7 hours", 7, block.getHours());
+    }
+
+    public final void testHoursAcrossFallBack() {
+        // Clocks go from 2 AM back to 1 AM on 2026-11-01.
+        UsageBlockBase block = block(2026, 10, 31, 22, 2026, 11, 1, 6);
+        assertEquals("10 PM to 6 AM across fall back should be 9 hours", 9, block.getHours());
+    }
+
+    public final void testHoursOfAMultiDayBlockAcrossFallBack() {
+        // Block 24951 on the dev copy, billed 29 hours.
+        UsageBlockBase block = block(2025, 11, 1, 0, 2025, 11, 2, 4);
+        assertEquals("Midnight Nov 1 to 4 AM Nov 2 2025, across fall back, should be 29 hours", 29, block.getHours());
+    }
+
+    private static UsageBlockBase block(int startYear, int startMonth, int startDay, int startHour,
+                                        int endYear, int endMonth, int endDay, int endHour) {
+        UsageBlockBase block = new UsageBlockBase();
+        block.setStartDate(date(startYear, startMonth, startDay, startHour));
+        block.setEndDate(date(endYear, endMonth, endDay, endHour));
+        return block;
+    }
+
+    private static Date date(int year, int month, int day, int hour) {
+        Calendar calendar = Calendar.getInstance();
+        calendar.clear();
+        calendar.set(year, month - 1, day, hour, 0, 0);
+        return calendar.getTime();
+    }
+}

src/org/uwpr/www/instrumentlog/JSONInstrumentUsageGetter.java

@@ -276,8 +276,8 @@ private JSONObject getForContiguousBlocks(List<UsageBlock> blocks,
 		event.put("projectId", Integer.valueOf(blocks.get(0).getProjectID()));
 		event.put("instrumentId", Integer.valueOf(blocks.get(0).getInstrumentID()));
 		event.put("title", String.valueOf(blocks.get(0).getProjectID()));
-		event.put("start", sd.toString());
-		event.put("end", ed.toString());
+		event.put("start", formatEventTime(sd));
+		event.put("end", formatEventTime(ed));
 		event.put("allDay", Boolean.FALSE);
 		event.put("editable", Boolean.FALSE);
 
@@ -363,6 +363,16 @@ private JSONObject getForContiguousBlocks(List<UsageBlock> blocks,
 		return event;
 	}
 
+	/**
+	 * Formats a block time for fullCalendar as the server's local date and time with no zone, for example
+	 * 2026-09-17T10:00:00.  fullCalendar displays a time with no zone at that hour in every browser time zone.
+	 * Date.toString() carries the JVM's zone, and a browser in another time zone converts it to its own hour.
+	 */
+	static String formatEventTime(Date date)
+	{
+		return new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss").format(date);
+	}
+
 	private Object addToCalenderLink(UsageBlock block) throws UnsupportedEncodingException {
 		/*
 			https://www.google.com/calendar/render?action=TEMPLATE&text=UWPR&dates=20140127T224000Z/20140320T221500Z&details=Some+Details&sf=true&output=xml

src/org/uwpr/www/instrumentlog/JSONInstrumentUsageGetterTest.java

@@ -0,0 +1,64 @@
+package org.uwpr.www.instrumentlog;
+
+import java.time.Instant;
+import java.util.Date;
+import java.util.TimeZone;
+
+import junit.framework.TestCase;
+
+/**
+ * formatEventTime() must return a block time as the wall-clock time in the server's zone, the zone the block's
+ * label is formatted in, with no zone in the string.  Each test starts from a fixed moment in UTC, so the
+ * expected hour depends on the server's zone.
+ */
+public class JSONInstrumentUsageGetterTest extends TestCase {
+
+    private TimeZone defaultZone;
+
+    protected void setUp() throws Exception {
+        super.setUp();
+        defaultZone = TimeZone.getDefault();
+    }
+
+    protected void tearDown() throws Exception {
+        TimeZone.setDefault(defaultZone);
+        super.tearDown();
+    }
+
+    public final void testEventTimeOnALosAngelesServer() {
+        TimeZone.setDefault(TimeZone.getTimeZone("America/Los_Angeles"));
+        assertEquals("17:00 UTC on 2026-09-17 should be sent as 10:00 from a Los Angeles server (UTC - 7)",
+                "2026-09-17T10:00:00", JSONInstrumentUsageGetter.formatEventTime(utc("2026-09-17T17:00:00Z")));
+    }
+
+    public final void testEventTimeOnALosAngelesServerAfterFallBack() {
+        TimeZone.setDefault(TimeZone.getTimeZone("America/Los_Angeles"));
+        assertEquals("14:00 UTC on 2026-11-01, after the clocks go back, "
+                        + "should be sent as 06:00 from a Los Angeles server (UTC - 8)",
+                "2026-11-01T06:00:00", JSONInstrumentUsageGetter.formatEventTime(utc("2026-11-01T14:00:00Z")));
+    }
+
+    public final void testEventTimeOnANewYorkServer() {
+        TimeZone.setDefault(TimeZone.getTimeZone("America/New_York"));
+        assertEquals("17:00 UTC on 2026-09-17 should be sent as 13:00 from a New York server (UTC - 4)",
+                "2026-09-17T13:00:00", JSONInstrumentUsageGetter.formatEventTime(utc("2026-09-17T17:00:00Z")));
+    }
+
+    public final void testEventTimeOnAKolkataServer() {
+        // Kolkata has no daylight saving time and a half-hour offset from UTC.
+        TimeZone.setDefault(TimeZone.getTimeZone("Asia/Kolkata"));
+        assertEquals("17:00 UTC on 2026-09-17 should be sent as 22:30 from a Kolkata server (UTC + 5:30)",
+                "2026-09-17T22:30:00", JSONInstrumentUsageGetter.formatEventTime(utc("2026-09-17T17:00:00Z")));
+    }
+
+    public final void testEventTimeOnAServerWithAFixedOffset() {
+        // A fixed offset has no daylight saving time, so in September it is an hour behind Pacific time.
+        TimeZone.setDefault(TimeZone.getTimeZone("GMT-08:00"));
+        assertEquals("17:00 UTC on 2026-09-17 should be sent as 09:00 from a GMT-08:00 server (UTC - 8)",
+                "2026-09-17T09:00:00", JSONInstrumentUsageGetter.formatEventTime(utc("2026-09-17T17:00:00Z")));
+    }
+
+    private static Date utc(String isoInstant) {
+        return Date.from(Instant.parse(isoInstant));
+    }
+}

src/org/uwpr/www/util/TimeUtils.java

@@ -36,21 +36,6 @@ public static Date makeBeginningOfDay(Date date)
         return startCal.getTime();
     }
 
-//    public static Date makeEndOfDay(Date date)
-//    {
-//        if(date == null)
-//        {
-//            return null;
-//        }
-//        Calendar endCal = Calendar.getInstance();
-//        endCal.setTime(date);
-//        endCal.set(Calendar.MILLISECOND, 0);
-//        endCal.set(Calendar.SECOND, 0);
-//        endCal.set(Calendar.MINUTE, 0);
-//        endCal.set(Calendar.HOUR_OF_DAY, 0); // 12:00 am
-//        return new Date(endCal.getTime().getTime() + MILLIS_IN_DAY - 1);
-//    }
-
     public static Date makeEndOfDay_12AM(Date date)
     {
         if(date == null)
@@ -63,7 +48,9 @@ public static Date makeEndOfDay_12AM(Date date)
         endCal.set(Calendar.SECOND, 0);
         endCal.set(Calendar.MINUTE, 0);
         endCal.set(Calendar.HOUR_OF_DAY, 0); // 12:00 am
-        return new Date(endCal.getTime().getTime() + MILLIS_IN_DAY);
+        // Add a calendar day, not 24 hours.  The day the clocks change is 23 or 25 hours long.
+        endCal.add(Calendar.DAY_OF_MONTH, 1);
+        return endCal.getTime();
     }
 
     public static String format(Date date)

src/org/uwpr/www/util/TimeUtilsTest.java

@@ -0,0 +1,54 @@
+package org.uwpr.www.util;
+
+import java.text.SimpleDateFormat;
+import java.util.Calendar;
+import java.util.Date;
+import java.util.TimeZone;
+
+import junit.framework.TestCase;
+
+/**
+ * makeEndOfDay_12AM() is the end boundary of the billing export and the scheduled-time views, so it must be
+ * midnight at the start of the next day, including on a day when the clocks change.
+ */
+public class TimeUtilsTest extends TestCase {
+
+    private TimeZone defaultZone;
+
+    protected void setUp() throws Exception {
+        super.setUp();
+        defaultZone = TimeZone.getDefault();
+        TimeZone.setDefault(TimeZone.getTimeZone("America/Los_Angeles"));
+    }
+
+    protected void tearDown() throws Exception {
+        TimeZone.setDefault(defaultZone);
+        super.tearDown();
+    }
+
+    public final void testEndOfAnOrdinaryDay() {
+        assertEquals("The end of 2026-09-17 should be midnight on 2026-09-18",
+                "2026-09-18 00:00", format(TimeUtils.makeEndOfDay_12AM(date(2026, 9, 17, 10))));
+    }
+
+    public final void testEndOfSpringForwardDay() {
+        assertEquals("The end of 2026-03-08, when clocks go forward, should be midnight on 2026-03-09",
+                "2026-03-09 00:00", format(TimeUtils.makeEndOfDay_12AM(date(2026, 3, 8, 10))));
+    }
+
+    public final void testEndOfFallBackDay() {
+        assertEquals("The end of 2026-11-01, when clocks go back, should be midnight on 2026-11-02",
+                "2026-11-02 00:00", format(TimeUtils.makeEndOfDay_12AM(date(2026, 11, 1, 10))));
+    }
+
+    private static String format(Date date) {
+        return new SimpleDateFormat("yyyy-MM-dd HH:mm").format(date);
+    }
+
+    private static Date date(int year, int month, int day, int hour) {
+        Calendar calendar = Calendar.getInstance();
+        calendar.clear();
+        calendar.set(year, month - 1, day, hour, 0, 0);
+        return calendar.getTime();
+    }
+}