MXS-1300: Reorganize and refactor tests

The tests are now sorted by command type. This allows for more consistent
test creation as tests can be done per source code file instead of per
object type.

Added helper functions for common testing operations. The two main ones
are doCommand, which executes a MaxCtrl command and returns a result, and
verifyCommand, that executes a command and verifies the result via the
REST API.

maxctrl/test_utils.js

@@ -15,6 +15,7 @@ module.exports = function() {
     this.expect = chai.expect
     this.host = 'http://localhost:8989/v1/'
 
+    // Start MaxScale, this should be called in the `before` handler of each test unit
     this.startMaxScale = function() {
         return new Promise(function(resolve, reject) {
             child_process.execFile("./start_maxscale.sh", function(err, stdout, stderr) {
@@ -26,6 +27,8 @@ module.exports = function() {
             })
         })
     };
+
+    // Stop MaxScale, this should be called in the `after` handler of each test unit
     this.stopMaxScale = function() {
         return new Promise(function(resolve, reject) {
             child_process.execFile("./stop_maxscale.sh", function(err, stdout, stderr) {
@@ -37,4 +40,21 @@ module.exports = function() {
             })
         })
     };
+
+    // Execute a single MaxCtrl command, returns a Promise
+    this.doCommand = function(command) {
+        var ctrl = require('./lib/core.js')
+        var opts = { extra_args: [ '--quiet'] }
+
+        return ctrl.execute(command.split(' '), opts)
+    }
+
+    // Execute a single MaxCtrl command and request a resource via the REST API,
+    // returns a Promise with the JSON format resource as an argument
+    this.verifyCommand = function(command, resource) {
+        return doCommand(command)
+            .then(function() {
+                return request.get(host + resource, {json: true})
+            })
+    };
 }