Began system/ with client

This will contain various factories (compounded in some cases) to
instantiate various parts of a coherent system.  It aims to replace
(as one of many pieces) the ClientDependencyFactory that's referenced
in the code, which is still part of rating-fw (internal LoVullo repo
from which liza is being liberated).

* src/system/client.js: Add module.
* test/system/clientTest.js: Add functional test case.

DEV-2296

src/system/client.js

@@ -0,0 +1,39 @@
+/**
+ * Client system
+ *
+ *  Copyright (C) 2017 LoVullo Associates, Inc.
+ *
+ *  This file is part of liza.
+ *
+ *  liza is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+"use strict";
+
+const MemoryStore = require( '../store' ).MemoryStore;
+
+
+/**
+ * Typical client system
+ *
+ * This serves as a factory of sorts for the user-facing client that runs in
+ * the web browser.
+ *
+ * This is incomplete; it will be added to as code is ported to liza.
+ */
+module.exports = {
+    data: {
+        diffStore: () => MemoryStore(),
+    },
+};

test/system/clientTest.js

@@ -0,0 +1,46 @@
+/**
+ * Tests instantiation of portions of the client system
+ *
+ *  Copyright (C) 2017 LoVullo Associates, Inc.
+ *
+ *  This file is part of liza.
+ *
+ *  liza is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * This is a functional test of the client system at large; these are _not_
+ * unit tests.
+ */
+
+"use strict";
+
+const root   = require( '../../' );
+const sut    = root.system.client;
+const expect = require( 'chai' ).expect;
+const Store  = root.store.Store;
+const Class  = require( 'easejs' ).Class;
+
+
+describe( 'client', () =>
+{
+    describe( 'data.diffStore', () =>
+    {
+        it( 'produces Store', () =>
+        {
+            const result = sut.data.diffStore();
+
+            expect( Class.isA( Store, result ) )
+                .to.be.true;
+        } );
+    } );
+} );