NODE-1049 only include primary server if there are no secondary serve… (

#194)

* NODE-1049 only include primary server if there are no secondary servers for readPrefrence secondaryPreferred

* minor correction to fix test error

* removed commented out code and stray 2

* minor tweak to test case to make less brittle

topologies/replset_state.js

@@ -759,15 +759,24 @@ function pickNearestMaxStalenessSeconds(self, readPreference) {
   }
 
   // Add primary to list if not a secondary read preference
-  if(self.primary && readPreference.preference != 'secondary') {
-    servers.push(self.primary);
+  if(self.primary 
+    && readPreference.preference != 'secondary' 
+    && readPreference.preference != 'secondaryPreferred') {
+      servers.push(self.primary);
   }
 
   // Add all the secondaries
   for(var i = 0; i < self.secondaries.length; i++) {
     servers.push(self.secondaries[i]);
   }
 
+  // If we have a secondaryPreferred readPreference and no server add the primary
+  if(self.primary 
+    && servers.length == 0 
+    && readPreference.preference != 'secondaryPreferred') {
+      servers.push(self.primary);
+  }
+
   // Filter by tags
   servers = filterByTags(readPreference, servers);
 
@@ -807,15 +816,24 @@ function pickNearest(self, readPreference) {
   var servers = [];
 
   // Add primary to list if not a secondary read preference
-  if(self.primary && readPreference.preference != 'secondary') {
-    servers.push(self.primary);
+  if(self.primary 
+    && readPreference.preference != 'secondary'
+    && readPreference.preference != 'secondaryPreferred') {
+      servers.push(self.primary);
   }
 
   // Add all the secondaries
   for(var i = 0; i < self.secondaries.length; i++) {
     servers.push(self.secondaries[i]);
   }
 
+  // If we have a secondaryPreferred readPreference and no server add the primary
+  if(servers.length == 0 
+    && self.primary
+    && readPreference.preference != 'secondaryPreferred') {
+      servers.push(self.primary);
+  }
+
   // Filter by tags
   servers = filterByTags(readPreference, servers);