add test case & close event parameter remove

lib/dirty/dirty.js

@@ -102,16 +102,20 @@ Dirty.prototype.close = function() {
   if (!this.path) {
     return;
   }
-
-	this._maybeFlush();
-
-	var self = this;
-	fs.close(this._fdRead, function() {
-		self.emit('read_close', 0);
-	});
-	fs.close(this._fdWrite, function() {
-		self.emit('write_close', 0);
-	});
+
+  this._maybeFlush();
+
+  var self = this;
+  if (this._fdRead) {
+    fs.close(this._fdRead, function() {
+      self.emit('read_close');
+    });
+  }
+  if (this._fdWrite) {
+    fs.close(this._fdWrite, function() {
+      self.emit('write_close');
+    });
+  }
 };
 
 // Called when a dirty connection is instantiated

test/test-api.js

@@ -127,8 +127,28 @@ function dirtyAPITests(file) {
           done();
         });
       });
+    });
+
+    describe('db file close', function(done) {
+      after(cleanup);
+
+      it('close', function(done) {
+        if (!file) {
+          console.log('N/A in transient mode');
+          return done();
+        }
+        var db = dirty(file);
+        db.on('load', function(length) {
+          db.set('close', 'close');
+          db.on('drain', function() {
+            db.close();
+          });
+        });
 
-
+        db.on('write_close',function() {
+          done();
+        });
+      });
     });
 
   });