Basic test for persistCachgedDatabase

lib/persistence.js

@@ -105,7 +105,7 @@ Persistence.prototype.persistCachedDatabase = function (cb) {
   async.waterfall([
     function (cb) {
       fs.exists(self.tempFilename, function (exists) {
-        if (exists) {
+        if (exists) {   // Shouldn't happen since ensureDatafileIntegrity removes the temp datafile
           fs.unlink(self.tempFilename, function (err) { return cb(err); });
         } else {
           return cb();
@@ -113,19 +113,27 @@ Persistence.prototype.persistCachedDatabase = function (cb) {
       });
     }
   , function (cb) {
-  console.log("==== 3");
-      fs.rename(self.filename, self.tempFilename, function (err) {
-        console.log("==== 4");
-
-        if (err) { return cb(err); }
-        fs.writeFile(self.filename, toPersist, function (err) {
-          console.log("==== 5");
-          if (err) { return cb(err); }
+      fs.exists(self.filename, function (exists) {
+        if (exists) {
+          fs.rename(self.filename, self.tempFilename, function (err) { return cb(err); });
+        } else {
+          return cb();
+        }
+      });  
+  }
+  , function (cb) {
+      fs.writeFile(self.filename, toPersist, function (err) { return cb(err); });
+    }
+  , function (cb) {
+      fs.exists(self.tempFilename, function (exists) {
+        if (exists) {
           fs.unlink(self.tempFilename, function (err) { return cb(err); });
-        });
+        } else {
+          return cb();
+        }
       });
     }
-  ], function (err) { return callback(err); })
+  ], function (err) { if (err) { return callback(err); } else { return callback(null); } })
 };
 
 

test/persistence.test.js

@@ -378,6 +378,26 @@ describe('Persistence', function () {
       });
     });
   
+    it('persistCachedDatabase should update the contents of the datafile', function (done) {
+      d.insert({ hello: 'world' }, function () {
+        d.find({}, function (err, docs) {
+          docs.length.should.equal(1);
+          
+          fs.unlinkSync(testDb);
+          fs.existsSync(testDb).should.equal(false);
+          
+          d.persistence.persistCachedDatabase(function (err) {
+            var contents = fs.readFileSync(testDb, 'utf8');
+            assert.isNull(err);
+            if (!contents.match(/^{"hello":"world","_id":"[0-9a-zA-Z]{16}"}\n$/)) {
+              throw "Datafile contents not as expected";
+            }
+            done();
+          });
+        });
+      });
+    });    
+  
     it.skip('If system crashes during a loadDatabase, the former version is not lost', function (done) {
       var cp, N = 150000, toWrite = "", i;