Add error message when provider does not exist

lib/plugins/deploy/deploy.js

@@ -105,6 +105,11 @@ class Deploy {
     this.hooks = {
       'before:deploy:deploy': () => BbPromise.bind(this)
         .then(() => {
+          const provider = this.serverless.service.provider.name;
+          if (!this.serverless.getProvider(provider)) {
+            const errorMessage = `The specified provider "${provider}" does not exist.`;
+            return BbPromise.reject(new this.serverless.classes.Error(errorMessage));
+          }
           if (this.options.function) {
             // If the user has given a function parameter, spawn a function deploy
             // and terminate execution right afterwards. We did not enter the

lib/plugins/deploy/deploy.test.js

@@ -20,6 +20,8 @@ describe('Deploy', () => {
     serverless = new Serverless();
     options = {};
     deploy = new Deploy(serverless, options);
+    deploy.serverless.providers = { validProvider: true };
+    deploy.serverless.service.provider.name = 'validProvider';
   });
 
   describe('#constructor()', () => {
@@ -90,5 +92,13 @@ describe('Deploy', () => {
         ),
       ]));
     });
+
+    it('should throw an error if provider does not exist', () => {
+      deploy.serverless.service.provider.name = 'nonExistentProvider';
+
+      return expect(deploy.hooks['before:deploy:deploy']()).to.be.rejectedWith(
+        'The specified provider "nonExistentProvider" does not exist.'
+      );
+    });
   });
 });