Index: src/test/org/codehaus/groovy/runtime/TimeCategoryTest.groovy
===================================================================
--- src/test/org/codehaus/groovy/runtime/TimeCategoryTest.groovy	(revision 0)
+++ src/test/org/codehaus/groovy/runtime/TimeCategoryTest.groovy	(revision 0)
@@ -0,0 +1,192 @@
+package org.codehaus.groovy.runtime
+
+import org.codehaus.groovy.runtime.TimeCategory
+import java.util.Calendar;
+import groovy.time.*
+
+/** 
+ * Tests the org.codehaus.groovy.runtime.TimeCategory class. 
+ * Most of these tests use January 1 as a start time to avoid 
+ * leap years and daylight savings time issues. 
+ * 
+ * @version $Revision$
+ */
+class TimeCategoryTest extends GroovyTestCase {
+
+	void testDurationArithmeticOnMilliseconds() {
+		use(TimeCategory) {
+			def midnight = new Date(100, 0, 1, 0, 0, 0) 
+			def oneSecondPastMidnight = new Date(100, 0, 1, 0, 0, 1) 
+			def twoSecondsPastMidnight = new Date(100, 0, 1, 0, 0, 2) 
+
+			assert (midnight + 1000.millisecond) == oneSecondPastMidnight
+			assert (midnight + 2000.milliseconds) == twoSecondsPastMidnight
+			assert (twoSecondsPastMidnight - 1000.millisecond) == oneSecondPastMidnight
+			assert (twoSecondsPastMidnight - 2000.milliseconds) == midnight
+		}
+	}
+	
+	void testDurationArithmeticOnSeconds() {
+		use(TimeCategory) {
+			def midnight = new Date(100, 0, 1, 0, 0, 0) 
+			def oneSecondPastMidnight = new Date(100, 0, 1, 0, 0, 1) 
+			def twoSecondsPastMidnight = new Date(100, 0, 1, 0, 0, 2) 
+
+			assert (midnight + 1.second) == oneSecondPastMidnight
+			assert (midnight + 2.seconds) == twoSecondsPastMidnight
+			assert (twoSecondsPastMidnight - 1.second) == oneSecondPastMidnight
+			assert (twoSecondsPastMidnight - 2.seconds) == midnight
+		}
+	}
+	
+	void testDurationArithmeticOnMinutes() {
+		use(TimeCategory) {
+			def midnight = new Date(100, 0, 1, 0, 0, 0) 
+			def oneMinutePastMidnight = new Date(100, 0, 1, 0, 1, 0) 
+			def twoMinutesPastMidnight = new Date(100, 0, 1, 0, 2, 0) 
+			
+			assert (midnight + 1.minute) == oneMinutePastMidnight
+			assert (midnight + 2.minutes) == twoMinutesPastMidnight
+			assert (twoMinutesPastMidnight - 60.seconds) == oneMinutePastMidnight
+			//assert (twoMinutesPastMidnight - 1.minute) == oneMinutePastMidnight //todo: this should work but fails
+			assert (twoMinutesPastMidnight - 120.seconds) == midnight
+			//assert (twoMinutesPastMidnight - 2.minutes) == midnight  //todo: this should work but fails
+		}
+	}
+	
+	void testDurationArithmeticOnHours() {
+		use(TimeCategory) {
+			def midnight = new Date(100, 0, 1, 0, 0, 0) 
+			def oneAM = new Date(100, 0, 1, 1, 0, 0) 
+			def twoAM = new Date(100, 0, 1, 2, 0, 0) 
+			
+			assert (midnight + 1.hour) == oneAM
+			assert (midnight + 2.hours) == twoAM
+			assert (twoAM - 3600.seconds) == oneAM 
+			//assert (twoAM - 1.hour) == oneAM //todo: this should work but fails
+			assert (twoAM - 7200.seconds) == midnight  
+			//assert (twoAM - 2.hours) == midnight  //todo: this should work but fails
+		}
+	}
+	
+	void testDurationArithmeticOnDays() {
+		use(TimeCategory) {
+			def januaryFirst = new Date(100, 0, 1, 0, 0, 0) 
+			def januarySecond = new Date(100, 0, 2, 0, 0, 0) 
+			def januaryThird = new Date(100, 0, 3, 0, 0, 0) 
+
+			assert (januaryFirst + 1.day) == januarySecond
+			assert (januaryFirst + 2.days) == januaryThird
+			assert (januaryThird - 1.day) == januarySecond
+			assert (januaryThird - 2.days) == januaryFirst
+		}	
+	}
+	
+	void testDurationArithmeticOnWeeks() {
+		use(TimeCategory) {
+			def firstWeek = new Date(100, 0, 1, 0, 0, 0) 
+			def secondWeek = new Date(100, 0, 8, 0, 0, 0) 
+			def thirdWeek = new Date(100, 0, 15, 0, 0, 0) 
+
+			assert (firstWeek + 1.week) == secondWeek
+			assert (firstWeek + 2.weeks) == thirdWeek
+			assert (thirdWeek - 1.week) == secondWeek
+			assert (thirdWeek - 2.weeks) == firstWeek
+		}	
+	}
+	
+	void testDurationArithmeticOnMonths() {
+		use(TimeCategory) {
+			def january = new Date(100, 0, 1, 0, 0, 0) 
+			def february = new Date(100, 1, 1, 0, 0, 0) 
+			def march = new Date(100, 2, 1, 0, 0, 0) 
+
+			assert (january + 1.month) == february
+			assert (january + 2.months) == march
+			assert (march - 1.month) == february
+			assert (march - 2.months) == january
+		}	
+	}
+	
+	void testDurationArithmeticOnYears() {
+		use(TimeCategory) {
+			def firstYear = new Date(100, 0, 1, 0, 0, 0) 
+			def secondYear = new Date(101, 0, 1, 0, 0, 0) 
+			def thirdYear = new Date(102, 0, 1, 0, 0, 0) 
+
+			assert (firstYear + 1.year) == secondYear
+			assert (firstYear + 2.years) == thirdYear
+			assert (thirdYear - 1.year) == secondYear
+			assert (thirdYear - 2.years) == firstYear
+		}	
+	}
+	
+
+	void testDateSubtractionOnSeconds() {
+		use(TimeCategory) {
+			def current = new Date(100, 0, 1, 0, 0, 0) 
+			def oneSecondLater = new Date(100, 0, 1, 0, 0, 1) 
+			def twoSecondsLater = new Date(100, 0, 1, 0, 0, 2) 
+			
+			def result = oneSecondLater - current 
+			assert result.seconds == 1
+			result = twoSecondsLater - current 
+			assert result.seconds == 2
+		}	
+	}
+
+	void testDateSubtractionOnMinutes() {
+		use(TimeCategory) {
+			def current = new Date(100, 0, 1, 0, 0, 0) 
+			def oneMinuteLater = new Date(100, 0, 1, 0, 1, 0) 
+			def twoMinutesLater = new Date(100, 0, 1, 0, 2, 0) 
+			
+			def result = oneMinuteLater - current 
+			assert result.minutes == 1
+			result = twoMinutesLater - current 
+			assert result.minutes == 2
+		}	
+	}
+
+	void testDateSubtractionOnHours() {
+		use(TimeCategory) {
+			def current = new Date(100, 0, 1, 0, 0, 0) 
+			def oneHourLater = new Date(100, 0, 1, 1, 0, 0) 
+			def twoHoursLater = new Date(100, 0, 1, 2, 0, 0) 
+			
+			def result = oneHourLater - current 
+			assert result.hours == 1
+			result = twoHoursLater - current 
+			assert result.hours == 2
+		}	
+	}
+
+	void testDateSubtractionOnDays() {
+		use(TimeCategory) {
+			def current = new Date(100, 0, 1, 0, 0, 0) 
+			def oneDayLater = new Date(100, 0, 2, 0, 0, 0) 
+			def twoDaysLater = new Date(100, 0, 3, 0, 0, 0) 
+			
+			def result = oneDayLater - current 
+			assert result.days == 1
+			result = twoDaysLater - current 
+			assert result.days == 2
+		}	
+	}
+
+	void testDateSubtraction_NoYearsOrMonths() {
+		use(TimeCategory) {
+			def yearOne = new Date(100, 0, 1, 0, 0, 0) 
+			def yearThree = new Date(102, 0, 1, 0, 0, 0) 
+			
+			def result = yearThree - yearOne
+			
+			//do NOT expect months and years to be 
+			//set on the result of date subtraction
+			assert result.years == 0
+			assert result.months == 0
+			
+		}	
+	}
+	
+}