correct naming of Generalinfos and added tests

src/GlobalInfos.test.js

@@ -0,0 +1,24 @@
+import React from "react";
+import GlobalInfos from "./GlobalInfos";
+
+describe('<GlobalInfos/>', function () {
+    it('always same instance ', function () {
+        GlobalInfos.enableDarkTheme(true);
+
+        expect(GlobalInfos.isDarkTheme()).toBe(true);
+
+        GlobalInfos.enableDarkTheme(false);
+
+        expect(GlobalInfos.isDarkTheme()).toBe(false);
+    });
+
+    it('test default theme', function () {
+        expect(GlobalInfos.isDarkTheme()).toBe(false);
+    });
+
+    it('test receive of stylesheet', function () {
+        const style = GlobalInfos.getThemeStyle();
+
+        expect(style.navitem).not.toBeNull();
+    });
+});