Complete set union is complete

Fixes #469

Author: bleroy

lib/index.js

@@ -167,7 +167,7 @@ lunr.Index.prototype.query = function (fn) {
      */
     var clause = query.clauses[i],
         terms = null,
-        clauseMatches = lunr.Set.complete
+        clauseMatches = lunr.Set.empty
 
     if (clause.usePipeline) {
       terms = this.pipeline.runString(clause.term, {

lib/set.js

@@ -35,7 +35,7 @@ lunr.Set.complete = {
   },
 
   union: function (other) {
-    return other
+    return this
   },
 
   contains: function () {

test/set_test.js

@@ -33,16 +33,18 @@ suite('lunr.Set', function () {
     })
 
     suite('complete set', function () {
-      test('contains element', function () {
+      test('union is complete', function () {
         var result = lunr.Set.complete.union(this.set)
         assert.isOk(result.contains('foo'))
+        assert.isOk(result.contains('bar'))
       })
     })
 
     suite('empty set', function () {
       test('contains element', function () {
         var result = lunr.Set.empty.union(this.set)
         assert.isOk(result.contains('foo'))
+        assert.isNotOk(result.contains('bar'))
       })
     })
 
@@ -90,6 +92,7 @@ suite('lunr.Set', function () {
       test('contains element', function () {
         var result = lunr.Set.complete.intersect(this.set)
         assert.isOk(result.contains('foo'))
+        assert.isNotOk(result.contains('bar'))
       })
     })
 
@@ -136,6 +139,7 @@ suite('lunr.Set', function () {
               result = target.intersect(lunr.Set.complete)
 
           assert.isOk(result.contains('foo'))
+          assert.isNotOk(result.contains('bar'))
         })
       })
     })