fix #93

Author: anidotnet

nitrite/src/main/java/org/dizitart/no2/internals/SearchService.java

@@ -171,12 +171,6 @@ private Set<NitriteId> sortIdSet(Collection<NitriteId> nitriteIdSet, FindOptions
             }
         }
 
-        if (sortedMap.size() == 0) {
-            // search was made using non existing field in the whole collection
-            // so we should not consider nullValueIds at all and send empty set
-            return Collections.emptySet();
-        }
-
         List<NitriteId> sortedValues;
         if (findOptions.getSortOrder() == SortOrder.Ascending) {
             sortedValues = new ArrayList<>(nullValueIds);

nitrite/src/test/java/org/dizitart/no2/CollectionFindTest.java

@@ -216,7 +216,7 @@ public void testFindLimitAndSort() {
     public void testFindSortOnNonExistingField() {
         insert();
         Cursor cursor = collection.find(sort("my-value", SortOrder.Descending));
-        assertEquals(cursor.size(), 0);
+        assertEquals(cursor.size(), 3);
     }
 
     @Test
@@ -238,7 +238,7 @@ public void testFindLimitAndSortInvalidField() {
         insert();
         Cursor cursor = collection.find(
                 sort("birthDay2", SortOrder.Descending).thenLimit(1, 2));
-        assertEquals(cursor.size(), 0);
+        assertEquals(cursor.size(), 2);
     }
 
     @Test
@@ -579,4 +579,20 @@ public void testIssue72() {
         assertNull(cursor.toList().get(0).get("startTime"));
         assertNotNull(cursor.toList().get(1).get("startTime"));
     }
+
+    @Test
+    public void testIssue93() {
+        NitriteCollection coll = db.getCollection("orderByOnNullableColumn2");
+
+        coll.remove(Filters.ALL);
+
+        Document doc = new Document().put("id", "test-2").put("group", "groupA");
+        assertEquals(1, coll.insert(doc).getAffectedCount());
+
+        doc = new Document().put("id", "test-1").put("group", "groupA");
+        assertEquals(1, coll.insert(doc).getAffectedCount());
+
+        Cursor cursor = coll.find(Filters.eq("group", "groupA"), FindOptions.sort("startTime", SortOrder.Descending));
+        assertEquals(2, cursor.size());
+    }
 }