Enable property to switch off random zone offsets

pom.xml

@@ -111,6 +111,7 @@
 						-ea
 						-Dvallang.test.seed=${buildNumber}
 						-Dvallang.random.partialDateTime=true
+						-Dvallang.random.zoneOffsets=true
 					</argLine>
 				</configuration>
 			</plugin>

src/main/java/io/usethesource/vallang/impl/primitive/DateTimeValues.java

@@ -230,6 +230,7 @@ public IString format(String format) {
     }
 
     private static long currentTotalOffset() {
+        // subjectief?
         return OffsetDateTime.now().getOffset().getTotalSeconds();
     }
 

src/main/java/io/usethesource/vallang/type/DateTimeType.java

@@ -77,6 +77,7 @@ private static long between(Random r, long a, long b) {
 	public IValue randomValue(Random random, IValueFactory vf, TypeStore store, Map<Type, Type> typeParameters,
 	        int maxDepth, int maxBreadth) {
 		boolean partialDateTime = "true".equals(System.getProperty("vallang.random.partialDateTime"));
+		boolean zoneOffsets = "true".equals(System.getProperty("vallang.random.zoneOffsets"));
 
         try {
 			if (partialDateTime && random.nextDouble() > 0.8) {
@@ -104,7 +105,7 @@ public IValue randomValue(Random random, IValueFactory vf, TypeStore store, Map<
 				Instant.now().getEpochSecond() + TimeUnit.DAYS.toSeconds(700)
 				), 0
 			);
-			if (random.nextDouble() > 0.5) {
+			if (!zoneOffsets || random.nextDouble() > 0.5) {
 				return vf.datetime(result.toEpochMilli());
 			}
 			ZoneOffset off = ZoneOffset.ofTotalSeconds((int)between(random, ChronoField.OFFSET_SECONDS));