diff --git a/lib/indexes.js b/lib/indexes.js
index de361b8..8022fac 100644
--- a/lib/indexes.js
+++ b/lib/indexes.js
@@ -19,6 +19,10 @@ function checkValueEquality (a, b) {
  * @param {Datastore} options.datastore Datastore on which the index is created
  * @param {Boolean} options.unique Optional, enforce a unique constraint (default: false)
  * @param {Boolean} options.sparse Optional, allow a sparse index (we can have documents for which fieldName is undefined) (default: false)
+ *                                 TODO: for now the sparse option doesn't work fully
+ *                                       don't use it. I will implement it in the future
+ *                                       in the meantime you can use non-unique, non-sparse indexes
+ *                                       for approx. the same behaviour
  */
 function Index (options) {
   this.fieldName = options.fieldName;
diff --git a/test/db.test.js b/test/db.test.js
index a43f541..88fb032 100644
--- a/test/db.test.js
+++ b/test/db.test.js
@@ -1109,7 +1109,7 @@ describe('Database', function () {
   });   // ==== End of 'Remove' ==== //
 
 
-  describe('Using indexes', function () {
+  describe.only('Using indexes', function () {
 
     describe('ensureIndex', function () {
 
@@ -1220,7 +1220,45 @@ describe('Database', function () {
         });
       });
 
-    });
+    });   // ==== End of 'ensureIndex' ==== //
+
+    describe('Indexing newly inserted documents', function () {
+
+      it('Newly inserted documents are indexed', function (done) {
+        d.ensureIndex({ fieldName: 'z' });
+        d.indexes.z.tree.getNumberOfKeys().should.equal(0);
+
+        d.insert({ a: 2, z: 'yes' }, function (err, newDoc) {
+          d.indexes.z.tree.getNumberOfKeys().should.equal(1);
+          assert.deepEqual(d.indexes.z.getMatching('yes'), [newDoc]);
+
+          d.insert({ a: 5, z: 'nope' }, function (err, newDoc) {
+            d.indexes.z.tree.getNumberOfKeys().should.equal(2);
+            assert.deepEqual(d.indexes.z.getMatching('nope'), [newDoc]);
+
+            done();
+          });
+        });
+      });
+
+      it('Can insert two docs at the same key for a non unique index', function (done) {
+        d.ensureIndex({ fieldName: 'z' });
+        d.indexes.z.tree.getNumberOfKeys().should.equal(0);
+
+        d.insert({ a: 2, z: 'yes' }, function (err, newDoc) {
+          d.indexes.z.tree.getNumberOfKeys().should.equal(1);
+          assert.deepEqual(d.indexes.z.getMatching('yes'), [newDoc]);
+
+          d.insert({ a: 5, z: 'yes' }, function (err, newDoc2) {
+            d.indexes.z.tree.getNumberOfKeys().should.equal(1);
+            assert.deepEqual(d.indexes.z.getMatching('yes'), [newDoc, newDoc2]);
+
+            done();
+          });
+        });
+      });
+
+    });   // ==== End of '' ==== //