Add validation for underscores in service name

Author: pmuens

shared/validate.js

@@ -22,7 +22,11 @@ module.exports = {
 
     // should not contain 'goog'
     if (name.match(/goog/)) {
-      throw Error('Your service should not contain the string "goog"');
+      throw new Error('Your service should not contain the string "goog"');
+    }
+
+    if (name.match(/_+/)) {
+      throw new Error('Your service name should not include underscores');
     }
 
     return BbPromise.resolve();

shared/validate.test.js

@@ -68,7 +68,13 @@ describe('Validate', () => {
       expect(() => googleCommand.validateServiceName()).toThrow(Error);
     });
 
-    it('should not throw an error if the service name does not contain the string "goog"', () => {
+    it('should throw an error if the service name contains underscores', () => {
+      serverless.service.service = 'service_name';
+
+      expect(() => googleCommand.validateServiceName()).toThrow(Error);
+    });
+
+    it('should not throw an error if the service name is valid', () => {
       serverless.service.service = 'service-name';
 
       expect(() => googleCommand.validateServiceName()).not.toThrow(Error);