Add unit tests for invalid commands.

lib/classes/PluginManager.test.js

@@ -1586,6 +1586,107 @@ describe('PluginManager', () => {
     });
   });
 
+  describe('#getCommand()', () => {
+    beforeEach(() => {
+      pluginManager.addPlugin(SynchronousPluginMock);
+      pluginManager.serverless.cli.loadedCommands = {
+        create: {
+          usage: 'Create new Serverless service',
+          lifecycleEvents: [
+            'create',
+          ],
+          options: {
+            template: {
+              usage: 'Template for the service. Available templates: ", "aws-nodejs", "..."',
+              shortcut: 't',
+            },
+          },
+          key: 'create',
+          pluginName: 'Create',
+        },
+        deploy: {
+          usage: 'Deploy a Serverless service',
+          configDependent: true,
+          lifecycleEvents: [
+            'cleanup',
+            'initialize',
+          ],
+          options: {
+            conceal: {
+              usage: 'Hide secrets from the output (e.g. API Gateway key values)',
+            },
+            stage: {
+              usage: 'Stage of the service',
+              shortcut: 's',
+            },
+          },
+          key: 'deploy',
+          pluginName: 'Deploy',
+          commands: {
+            function: {
+              usage: 'Deploy a single function from the service',
+              lifecycleEvents: [
+                'initialize',
+                'packageFunction',
+                'deploy',
+              ],
+              options: {
+                function: {
+                  usage: 'Name of the function',
+                  shortcut: 'f',
+                  required: true,
+                },
+              },
+              key: 'deploy:function',
+              pluginName: 'Deploy',
+            },
+            list: {
+              usage: 'List deployed version of your Serverless Service',
+              lifecycleEvents: [
+                'log',
+              ],
+              key: 'deploy:list',
+              pluginName: 'Deploy',
+              commands: {
+                functions: {
+                  usage: 'List all the deployed functions and their versions',
+                  lifecycleEvents: [
+                    'log',
+                  ],
+                  key: 'deploy:list:functions',
+                  pluginName: 'Deploy',
+                },
+              },
+            },
+          },
+        },
+      };
+    });
+    it('should give a suggestion for an unknown command', (done) => {
+      try {
+        pluginManager.getCommand(['creet']);
+        done('Test failed. Expected an error to be thrown');
+      } catch (error) {
+        expect(error.name).to.eql('ServerlessError');
+        expect(error.message).to.eql('Serverless command "creet" not found. ' +
+          'Did you mean "create"? Run "serverless help" for a list of all available commands.');
+        done();
+      }
+    });
+
+    it('should not give a suggestion for valid top level command', (done) => {
+      try {
+        pluginManager.getCommand(['deploy', 'function-misspelled']);
+        done('Test failed. Expected an error to be thrown');
+      } catch (error) {
+        expect(error.name).to.eql('ServerlessError');
+        expect(error.message).to.eql('"function-misspelled" is not a valid sub command. '
+          + 'Run "serverless deploy" to see a more helpful error message for this command.');
+        done();
+      }
+    });
+  });
+
   describe('#spawn()', () => {
     it('should throw an error when the given command is not available', () => {
       pluginManager.addPlugin(EntrypointPluginMock);