feat(test): new protocol (#2)

Plugins are now testable.

packages/xo-server-test-plugin/README.md

@@ -13,3 +13,45 @@ Or globally:
 ```
 > npm i -g vatesfr/xo-server-test-plugin
 ```
+
+## Documentation
+
+### Plugin life cyle
+
+#### Initialization
+
+When xo-server starts, it initializes plugins.
+
+#### Loading plugins
+
+After initializing the plugins, the xo-server load them.
+
+#### Test
+
+XO clients send data to xo-server for testing the configuration and saving it if successful.
+
+### Principal Methods
+
+#### The default export
+
+It is  just a factory function which will create an instance of the plugin. Usually it will be called only once, at startup.
+Its only parameter is an object which currently only contains the instance of the currently running xo-server.
+
+#### `configure(configuration) `
+
+This method is called each time the plugin is (re-)configured.
+Its only parameter is an object which contains the configuration values.
+
+#### `load() `
+
+This method is called to load the plugin.
+
+#### `unload() `
+
+This method is called to unload the plugin.
+
+#### `test(data) `
+
+This method is called if the test option is activated.
+Its only parameter is an object which contains the test values. 
+

packages/xo-server-test-plugin/index.js

@@ -15,6 +15,18 @@ exports.configurationSchema = {
   required: ['foo']
 }
 
+// This (optional) schema is used to test the configuration 
+// of the plugin.
+exports.testSchema = {
+  type: 'object',
+  properties: {
+    test: {
+       type: 'string'
+    }
+  },
+  required: ['test']
+}
+
 // The default export is just a factory function which will create an
 // instance of the plugin.
 // Usually it will be called only once, at startup.
@@ -22,7 +34,6 @@ exports.configurationSchema = {
 // Its only parameter is an object which currently only contains a
 // `xo` property: the instance of the currently running xo-server.
 exports.default = function (opts) {
-
   // For simplicity's sake, this plugin returns a plain object, but
   // usually it returns a new instance of an existing class.
   return {
@@ -52,6 +63,16 @@ exports.default = function (opts) {
     // Note: will only be called if the plugin is currently loaded.
     unload: function () {
       console.log('stub unloaded')
+    },
+
+    // This (optional) method is called to test the configuration of the plugin.
+    // Note 1: will only be called if the plugin has been successfully configured and is loaded.
+    // Note 2: before being called, the test configuration is validated
+    // against the provided test data.
+    // Note 3: will only be called if the test option is activated.
+    test: function (data) {
+      console.log('the configuration is about to be tested')
+      // TODO: test the configuration, i.e, use the main feature of the plugin and throws any errors.
     }
   }
 }