Create Error tests, fix stupid typo found by them

lib/sequelize.js

@@ -153,7 +153,7 @@ module.exports = (function() {
   /**
    * Expose Sequelize Error types
    */
-  Sequelize.prototype.Errpr = Sequelize.Errpr =
+  Sequelize.prototype.Error = Sequelize.Error =
     sequelizeErrors.BaseError
   Sequelize.prototype.ValidationError = Sequelize.ValidationError =
     sequelizeErrors.ValidationError

test/error.test.js

+/* jshint camelcase: false */
+var chai      = require('chai')
+  , expect    = chai.expect
+  , Support   = require(__dirname + '/support')
+  , Sequelize = Support.Sequelize
+  // , sinon     = require('sinon')
+
+chai.Assertion.includeStack = true
+
+describe.only(Support.getTestDialectTeaser("Sequelize Errors"), function () {
+  describe('API Surface', function() {
+    it('Should have the Error constructors exposed', function() {
+      expect(Sequelize).to.have.property('Error')
+      expect(Sequelize).to.have.property('ValidationError')
+      var sequelize = new Sequelize();
+      expect(sequelize).to.have.property('Error')
+      expect(sequelize).to.have.property('ValidationError')
+    })
+    it('Sequelize Errors instances should be instances of Error', function() {
+      var error = new Sequelize.Error();
+      var validationError = new Sequelize.ValidationError();
+
+
+      var sequelize = new Sequelize();
+      var instError = new sequelize.Error();
+      var instValidationError = new sequelize.ValidationError();
+
+      expect(error).to.be.instanceOf(Error)
+      expect(validationError).to.be.instanceOf(Error)
+      expect(instError).to.be.instanceOf(Error)
+      expect(instValidationError).to.be.instanceOf(Error)
+    })
+  })
+})