Fix Range.restrictTo to work with non-intersecting ranges(#13334)

Also adds a special case for isSubsetOf with two empty ranges.

Change-Id: I9b4c854051bd760bbac05c7a0bc2e5418371e90e

2 files changed, 30 insertions, 3 deletions

diff --git a/shared/src/com/vaadin/shared/ui/grid/Range.java b/shared/src/com/vaadin/shared/ui/grid/Range.java
index 2054845320..6be9e04cbc 100644
--- a/shared/src/com/vaadin/shared/ui/grid/Range.java
+++ b/shared/src/com/vaadin/shared/ui/grid/Range.java
@@ -177,6 +177,10 @@ public final class Range implements Serializable {
      *         range
      */
     public boolean isSubsetOf(final Range other) {
+        if (isEmpty() && other.isEmpty()) {
+            return true;
+        }
+
         return other.getStart() <= getStart() && getEnd() <= other.getEnd();
     }
 
@@ -411,8 +415,10 @@ public final class Range implements Serializable {
      * @return a bounded range
      */
     public Range restrictTo(Range bounds) {
-        boolean startWithin = getStart() >= bounds.getStart();
-        boolean endWithin = getEnd() <= bounds.getEnd();
+        boolean startWithin = bounds.contains(getStart());
+        boolean endWithin = bounds.contains(getEnd());
+        boolean boundsWithin = getStart() < bounds.getStart()
+                && getEnd() >= bounds.getEnd();
 
         if (startWithin) {
             if (endWithin) {
@@ -423,8 +429,10 @@ public final class Range implements Serializable {
         } else {
             if (endWithin) {
                 return Range.between(bounds.getStart(), getEnd());
-            } else {
+            } else if (boundsWithin) {
                 return bounds;
+            } else {
+                return Range.withLength(getStart(), 0);
             }
         }
     }
diff --git a/shared/tests/src/com/vaadin/shared/ui/grid/RangeTest.java b/shared/tests/src/com/vaadin/shared/ui/grid/RangeTest.java
index ab67b22d0b..e3cae858ee 100644
--- a/shared/tests/src/com/vaadin/shared/ui/grid/RangeTest.java
+++ b/shared/tests/src/com/vaadin/shared/ui/grid/RangeTest.java
@@ -372,6 +372,7 @@ public class RangeTest {
         assertTrue(r2 == r3);
     }
 
+    @Test
     public void restrictTo_notInterstecting() {
         Range r1 = Range.between(5, 10);
         Range r2 = Range.between(15, 20);
@@ -385,6 +386,7 @@ public class RangeTest {
                 r4.isEmpty());
     }
 
+    @Test
     public void restrictTo_startOutside() {
         Range r1 = Range.between(5, 10);
         Range r2 = Range.between(7, 15);
@@ -392,8 +394,11 @@ public class RangeTest {
         Range r3 = r1.restrictTo(r2);
 
         assertEquals(Range.between(7, 10), r3);
+
+        assertEquals(r2.restrictTo(r1), r3);
     }
 
+    @Test
     public void restrictTo_endOutside() {
         Range r1 = Range.between(5, 10);
         Range r2 = Range.between(4, 7);
@@ -401,6 +406,20 @@ public class RangeTest {
         Range r3 = r1.restrictTo(r2);
 
         assertEquals(Range.between(5, 7), r3);
+
+        assertEquals(r2.restrictTo(r1), r3);
+    }
+
+    @Test
+    public void restrictTo_empty() {
+        Range r1 = Range.between(5, 10);
+        Range r2 = Range.between(0, 0);
+
+        Range r3 = r1.restrictTo(r2);
+        assertTrue(r3.isEmpty());
+
+        Range r4 = r2.restrictTo(r1);
+        assertTrue(r4.isEmpty());
     }
 
 }