diff --git a/js-src/00-core.js b/js-src/00-core.js
index e774602..5ff4e57 100644
--- a/js-src/00-core.js
+++ b/js-src/00-core.js
@@ -19,6 +19,10 @@ const SF = (function () {
       .replace(/"/g, '"');
   };
 
+  sf.assert = function (cond, message) {
+    if (!cond) throw new Error('[SolverForge] ' + message);
+  };
+
   sf.el = function (tag, attrs) {
     var children = Array.prototype.slice.call(arguments, 2);
     var el = document.createElement(tag);
diff --git a/js-src/03-buttons.js b/js-src/03-buttons.js
index 583522b..842f295 100644
--- a/js-src/03-buttons.js
+++ b/js-src/03-buttons.js
@@ -6,6 +6,8 @@
   'use strict';
 
   sf.createButton = function (config) {
+    sf.assert(config, 'createButton(config) requires a configuration object');
+
     var classes = ['sf-btn'];
 
     if (config.variant) classes.push('sf-btn--' + config.variant);
@@ -23,6 +25,8 @@
 
     if (config.disabled) btn.disabled = true;
 
+    sf.assert(!config.onClick || typeof config.onClick === 'function', 'createButton(onClick) must be a function');
+
     if (config.icon) {
       var icon = sf.el('i', { className: 'fa-solid ' + config.icon });
       btn.appendChild(icon);
diff --git a/js-src/04-header.js b/js-src/04-header.js
index 95d6187..4c6c62a 100644
--- a/js-src/04-header.js
+++ b/js-src/04-header.js
@@ -6,6 +6,8 @@
   'use strict';
 
   sf.createHeader = function (config) {
+    sf.assert(config, 'createHeader(config) requires a configuration object');
+
     var header = sf.el('header', { className: 'sf-header' });
     var controls = {
       actions: null,
@@ -38,9 +40,12 @@
 
     // Nav tabs
     if (config.tabs && config.tabs.length > 0) {
+      sf.assert(Array.isArray(config.tabs), 'createHeader(config.tabs) expects an array');
       var nav = sf.el('nav', { className: 'sf-header-nav' });
       controls.nav = nav;
       config.tabs.forEach(function (tab) {
+        sf.assert(tab && tab.id, 'createHeader tab entries require an id');
+        sf.assert(typeof tab.label === 'string', 'createHeader tab entries require a label');
         var btn = sf.el('button', {
           className: 'sf-nav-btn' + (tab.active ? ' active' : ''),
           dataset: { tab: tab.id },
@@ -61,6 +66,12 @@
 
     // Action buttons
     if (config.actions) {
+      sf.assert(typeof config.actions === 'object', 'createHeader(config.actions) expects an object');
+      sf.assert(!config.actions.onSolve || typeof config.actions.onSolve === 'function', 'createHeader(config.actions.onSolve) must be a function');
+      sf.assert(!config.actions.onStop || typeof config.actions.onStop === 'function', 'createHeader(config.actions.onStop) must be a function');
+      sf.assert(!config.actions.onAnalyze || typeof config.actions.onAnalyze === 'function', 'createHeader(config.actions.onAnalyze) must be a function');
+      sf.assert(!config.onTabChange || typeof config.onTabChange === 'function', 'createHeader(config.onTabChange) must be a function');
+
       var actions = sf.el('div', { className: 'sf-header-actions' });
       controls.actions = actions;
 
diff --git a/js-src/06-modal.js b/js-src/06-modal.js
index 9698d0c..8c8c096 100644
--- a/js-src/06-modal.js
+++ b/js-src/06-modal.js
@@ -6,6 +6,9 @@
   'use strict';
 
   sf.createModal = function (config) {
+    sf.assert(config, 'createModal(config) requires a configuration object');
+    sf.assert(!config.footer || Array.isArray(config.footer), 'createModal(config.footer) must be an array');
+
     var overlay = sf.el('div', { className: 'sf-modal-overlay' });
     var dialog = sf.el('div', { className: 'sf-modal' });
     var body = sf.el('div', { className: 'sf-modal-body' });
diff --git a/js-src/07-tabs.js b/js-src/07-tabs.js
index 1048dae..c1dc694 100644
--- a/js-src/07-tabs.js
+++ b/js-src/07-tabs.js
@@ -17,6 +17,9 @@
   };
 
   sf.createTabs = function (config) {
+    sf.assert(config, 'createTabs(config) requires a configuration object');
+    sf.assert(Array.isArray(config.tabs), 'createTabs(config.tabs) must be an array');
+
     var container = sf.el('div', { className: 'sf-tabs-container' });
     var tabsId = sf.uid('sf-tabs');
 
diff --git a/js-src/08-table.js b/js-src/08-table.js
index 430ab89..5bdd770 100644
--- a/js-src/08-table.js
+++ b/js-src/08-table.js
@@ -6,6 +6,10 @@
   'use strict';
 
   sf.createTable = function (config) {
+    sf.assert(config, 'createTable(config) requires a configuration object');
+    sf.assert(!config.columns || Array.isArray(config.columns), 'createTable(config.columns) must be an array');
+    sf.assert(!config.rows || Array.isArray(config.rows), 'createTable(config.rows) must be an array');
+
     var wrapper = sf.el('div', { className: 'sf-table-container' });
     var table = sf.el('table', { className: 'sf-table' });
 
diff --git a/js-src/09-toast.js b/js-src/09-toast.js
index d7e85ac..112d469 100644
--- a/js-src/09-toast.js
+++ b/js-src/09-toast.js
@@ -15,6 +15,8 @@
   }
 
   sf.showToast = function (config) {
+    sf.assert(config, 'showToast(config) requires a configuration object');
+
     ensureContainer();
 
     var variant = config.variant || 'danger';
diff --git a/js-src/10-backend.js b/js-src/10-backend.js
index 0c7a9cb..639ae8a 100644
--- a/js-src/10-backend.js
+++ b/js-src/10-backend.js
@@ -7,6 +7,7 @@
   'use strict';
 
   sf.createBackend = function (config) {
+    config = config || {};
     var type = config.type || 'axum';
     if (type === 'tauri') return createTauriBackend(config);
     return createHttpBackend(config);
@@ -97,6 +98,10 @@
   /* ── Tauri IPC backend ── */
 
   function createTauriBackend(config) {
+    sf.assert(typeof config === 'object', 'createBackend({}) is required for Tauri adapter');
+    sf.assert(typeof config.invoke === 'function', 'Tauri backend requires config.invoke');
+    sf.assert(typeof config.listen === 'function', 'Tauri backend requires config.listen');
+
     var invoke = config.invoke;
     var listen = config.listen;
     var commands = config.commands || {};
diff --git a/js-src/11-solver.js b/js-src/11-solver.js
index bf15201..d42dec6 100644
--- a/js-src/11-solver.js
+++ b/js-src/11-solver.js
@@ -7,6 +7,16 @@
   'use strict';
 
   sf.createSolver = function (config) {
+    sf.assert(config, 'createSolver(config) requires a configuration object');
+    sf.assert(config.backend, 'createSolver(config.backend) is required');
+    sf.assert(config.backend.createSchedule && typeof config.backend.createSchedule === 'function', 'createSolver(config.backend.createSchedule) must be a function');
+    sf.assert(config.backend.streamEvents && typeof config.backend.streamEvents === 'function', 'createSolver(config.backend.streamEvents) must be a function');
+    sf.assert(config.backend.getSchedule && typeof config.backend.getSchedule === 'function', 'createSolver(config.backend.getSchedule) must be a function');
+    sf.assert(!config.onUpdate || typeof config.onUpdate === 'function', 'createSolver(config.onUpdate) must be a function');
+    sf.assert(!config.onComplete || typeof config.onComplete === 'function', 'createSolver(config.onComplete) must be a function');
+    sf.assert(!config.onAnalysis || typeof config.onAnalysis === 'function', 'createSolver(config.onAnalysis) must be a function');
+    sf.assert(!config.onError || typeof config.onError === 'function', 'createSolver(config.onError) must be a function');
+
     var backend = config.backend;
     var statusBar = config.statusBar;
     var closeStream = null;
diff --git a/js-src/12-api-guide.js b/js-src/12-api-guide.js
index 587c407..b350660 100644
--- a/js-src/12-api-guide.js
+++ b/js-src/12-api-guide.js
@@ -7,8 +7,11 @@
   'use strict';
 
   sf.createApiGuide = function (config) {
+    sf.assert(config, 'createApiGuide(config) requires a configuration object');
+    sf.assert(Array.isArray(config.endpoints), 'createApiGuide(config.endpoints) must be an array');
+
     var guide = sf.el('div', { className: 'sf-api-guide' });
-    var endpoints = config.endpoints || [];
+    var endpoints = config.endpoints;
 
     endpoints.forEach(function (ep) {
       var section = sf.el('div', { className: 'sf-api-section' });
@@ -40,6 +43,8 @@
   };
 
   sf.createFooter = function (config) {
+    sf.assert(config, 'createFooter(config) requires a configuration object');
+
     var footer = sf.el('footer', { className: 'sf-footer' });
     if (config.links) {
       config.links.forEach(function (link, i) {
diff --git a/js-src/13-rail.js b/js-src/13-rail.js
index a89973b..3908285 100644
--- a/js-src/13-rail.js
+++ b/js-src/13-rail.js
@@ -9,6 +9,9 @@
   sf.rail = {};
 
   sf.rail.createHeader = function (config) {
+    sf.assert(config, 'createHeader(config) requires a configuration object');
+    sf.assert(!config.columns || Array.isArray(config.columns), 'createHeader(config.columns) expects an array');
+
     var labelWidth = config.labelWidth || 200;
     var columns = config.columns || [];
 
@@ -32,6 +35,8 @@
   };
 
   sf.rail.createCard = function (config) {
+    sf.assert(config, 'createCard(config) requires a configuration object');
+
     var labelWidth = config.labelWidth || 200;
     var card = sf.el('div', { className: 'sf-resource-card' });
 
@@ -136,6 +141,10 @@
   };
 
   sf.rail.addBlock = function (rail, config) {
+    sf.assert(rail, 'addBlock(rail) requires a rail element');
+    sf.assert(config && config.horizon != null, 'addBlock(config.horizon) is required');
+    sf.assert(config.start != null && config.end != null, 'addBlock(config.start/config.end) are required');
+
     var horizon = config.horizon || 1;
     var startPct = (config.start / horizon) * 100;
     var widthPct = ((config.end - config.start) / horizon) * 100;
@@ -175,6 +184,10 @@
   };
 
   sf.rail.addChangeover = function (rail, config) {
+    sf.assert(rail, 'addChangeover(rail) requires a rail element');
+    sf.assert(config && config.horizon != null, 'addChangeover(config.horizon) is required');
+    sf.assert(config.start != null && config.end != null, 'addChangeover(config.start/config.end) are required');
+
     var horizon = config.horizon || 1;
     var startPct = (config.start / horizon) * 100;
     var widthPct = ((config.end - config.start) / horizon) * 100;
diff --git a/js-src/14-gantt.js b/js-src/14-gantt.js
index e5108b5..8177626 100644
--- a/js-src/14-gantt.js
+++ b/js-src/14-gantt.js
@@ -9,6 +9,7 @@
   sf.gantt = {};
 
   sf.gantt.create = function (config) {
+    config = config || {};
     var instanceId = sf.uid('sf-gantt');
     var chartPaneId = config.chartPane || (instanceId + '-chart-pane');
     var gridPaneId = config.gridPane || (instanceId + '-grid-pane');
@@ -78,12 +79,15 @@
     var ctrl = { el: wrapper };
 
     ctrl.mount = function (parent) {
+      sf.assert(parent, 'gantt.mount(parent) requires a mount target');
       var target = typeof parent === 'string' ? document.getElementById(parent) : parent;
+      sf.assert(target, 'gantt.mount(parent) target not found: ' + parent);
       target.appendChild(wrapper);
       initSplit();
     };
 
     ctrl.setTasks = function (newTasks) {
+      sf.assert(Array.isArray(newTasks), 'gantt.setTasks(tasks) expects an array');
       tasks = newTasks;
       renderGrid(newTasks);
       renderChart(newTasks);
diff --git a/static/sf/sf.js b/static/sf/sf.js
index acec9cb..7e4db60 100644
--- a/static/sf/sf.js
+++ b/static/sf/sf.js
@@ -19,6 +19,10 @@ const SF = (function () {
       .replace(/"/g, '"');
   };
 
+  sf.assert = function (cond, message) {
+    if (!cond) throw new Error('[SolverForge] ' + message);
+  };
+
   sf.el = function (tag, attrs) {
     var children = Array.prototype.slice.call(arguments, 2);
     var el = document.createElement(tag);
@@ -172,6 +176,8 @@ const SF = (function () {
   'use strict';
 
   sf.createButton = function (config) {
+    sf.assert(config, 'createButton(config) requires a configuration object');
+
     var classes = ['sf-btn'];
 
     if (config.variant) classes.push('sf-btn--' + config.variant);
@@ -189,6 +195,8 @@ const SF = (function () {
 
     if (config.disabled) btn.disabled = true;
 
+    sf.assert(!config.onClick || typeof config.onClick === 'function', 'createButton(onClick) must be a function');
+
     if (config.icon) {
       var icon = sf.el('i', { className: 'fa-solid ' + config.icon });
       btn.appendChild(icon);
@@ -226,6 +234,8 @@ const SF = (function () {
   'use strict';
 
   sf.createHeader = function (config) {
+    sf.assert(config, 'createHeader(config) requires a configuration object');
+
     var header = sf.el('header', { className: 'sf-header' });
     var controls = {
       actions: null,
@@ -258,9 +268,12 @@ const SF = (function () {
 
     // Nav tabs
     if (config.tabs && config.tabs.length > 0) {
+      sf.assert(Array.isArray(config.tabs), 'createHeader(config.tabs) expects an array');
       var nav = sf.el('nav', { className: 'sf-header-nav' });
       controls.nav = nav;
       config.tabs.forEach(function (tab) {
+        sf.assert(tab && tab.id, 'createHeader tab entries require an id');
+        sf.assert(typeof tab.label === 'string', 'createHeader tab entries require a label');
         var btn = sf.el('button', {
           className: 'sf-nav-btn' + (tab.active ? ' active' : ''),
           dataset: { tab: tab.id },
@@ -281,6 +294,12 @@ const SF = (function () {
 
     // Action buttons
     if (config.actions) {
+      sf.assert(typeof config.actions === 'object', 'createHeader(config.actions) expects an object');
+      sf.assert(!config.actions.onSolve || typeof config.actions.onSolve === 'function', 'createHeader(config.actions.onSolve) must be a function');
+      sf.assert(!config.actions.onStop || typeof config.actions.onStop === 'function', 'createHeader(config.actions.onStop) must be a function');
+      sf.assert(!config.actions.onAnalyze || typeof config.actions.onAnalyze === 'function', 'createHeader(config.actions.onAnalyze) must be a function');
+      sf.assert(!config.onTabChange || typeof config.onTabChange === 'function', 'createHeader(config.onTabChange) must be a function');
+
       var actions = sf.el('div', { className: 'sf-header-actions' });
       controls.actions = actions;
 
@@ -483,6 +502,9 @@ const SF = (function () {
   'use strict';
 
   sf.createModal = function (config) {
+    sf.assert(config, 'createModal(config) requires a configuration object');
+    sf.assert(!config.footer || Array.isArray(config.footer), 'createModal(config.footer) must be an array');
+
     var overlay = sf.el('div', { className: 'sf-modal-overlay' });
     var dialog = sf.el('div', { className: 'sf-modal' });
     var body = sf.el('div', { className: 'sf-modal-body' });
@@ -585,6 +607,9 @@ const SF = (function () {
   };
 
   sf.createTabs = function (config) {
+    sf.assert(config, 'createTabs(config) requires a configuration object');
+    sf.assert(Array.isArray(config.tabs), 'createTabs(config.tabs) must be an array');
+
     var container = sf.el('div', { className: 'sf-tabs-container' });
     var tabsId = sf.uid('sf-tabs');
 
@@ -628,6 +653,10 @@ const SF = (function () {
   'use strict';
 
   sf.createTable = function (config) {
+    sf.assert(config, 'createTable(config) requires a configuration object');
+    sf.assert(!config.columns || Array.isArray(config.columns), 'createTable(config.columns) must be an array');
+    sf.assert(!config.rows || Array.isArray(config.rows), 'createTable(config.rows) must be an array');
+
     var wrapper = sf.el('div', { className: 'sf-table-container' });
     var table = sf.el('table', { className: 'sf-table' });
 
@@ -695,6 +724,8 @@ const SF = (function () {
   }
 
   sf.showToast = function (config) {
+    sf.assert(config, 'showToast(config) requires a configuration object');
+
     ensureContainer();
 
     var variant = config.variant || 'danger';
@@ -749,6 +780,7 @@ const SF = (function () {
   'use strict';
 
   sf.createBackend = function (config) {
+    config = config || {};
     var type = config.type || 'axum';
     if (type === 'tauri') return createTauriBackend(config);
     return createHttpBackend(config);
@@ -839,6 +871,10 @@ const SF = (function () {
   /* ── Tauri IPC backend ── */
 
   function createTauriBackend(config) {
+    sf.assert(typeof config === 'object', 'createBackend({}) is required for Tauri adapter');
+    sf.assert(typeof config.invoke === 'function', 'Tauri backend requires config.invoke');
+    sf.assert(typeof config.listen === 'function', 'Tauri backend requires config.listen');
+
     var invoke = config.invoke;
     var listen = config.listen;
     var commands = config.commands || {};
@@ -887,6 +923,16 @@ const SF = (function () {
   'use strict';
 
   sf.createSolver = function (config) {
+    sf.assert(config, 'createSolver(config) requires a configuration object');
+    sf.assert(config.backend, 'createSolver(config.backend) is required');
+    sf.assert(config.backend.createSchedule && typeof config.backend.createSchedule === 'function', 'createSolver(config.backend.createSchedule) must be a function');
+    sf.assert(config.backend.streamEvents && typeof config.backend.streamEvents === 'function', 'createSolver(config.backend.streamEvents) must be a function');
+    sf.assert(config.backend.getSchedule && typeof config.backend.getSchedule === 'function', 'createSolver(config.backend.getSchedule) must be a function');
+    sf.assert(!config.onUpdate || typeof config.onUpdate === 'function', 'createSolver(config.onUpdate) must be a function');
+    sf.assert(!config.onComplete || typeof config.onComplete === 'function', 'createSolver(config.onComplete) must be a function');
+    sf.assert(!config.onAnalysis || typeof config.onAnalysis === 'function', 'createSolver(config.onAnalysis) must be a function');
+    sf.assert(!config.onError || typeof config.onError === 'function', 'createSolver(config.onError) must be a function');
+
     var backend = config.backend;
     var statusBar = config.statusBar;
     var closeStream = null;
@@ -990,8 +1036,11 @@ const SF = (function () {
   'use strict';
 
   sf.createApiGuide = function (config) {
+    sf.assert(config, 'createApiGuide(config) requires a configuration object');
+    sf.assert(Array.isArray(config.endpoints), 'createApiGuide(config.endpoints) must be an array');
+
     var guide = sf.el('div', { className: 'sf-api-guide' });
-    var endpoints = config.endpoints || [];
+    var endpoints = config.endpoints;
 
     endpoints.forEach(function (ep) {
       var section = sf.el('div', { className: 'sf-api-section' });
@@ -1023,6 +1072,8 @@ const SF = (function () {
   };
 
   sf.createFooter = function (config) {
+    sf.assert(config, 'createFooter(config) requires a configuration object');
+
     var footer = sf.el('footer', { className: 'sf-footer' });
     if (config.links) {
       config.links.forEach(function (link, i) {
@@ -1048,6 +1099,9 @@ const SF = (function () {
   sf.rail = {};
 
   sf.rail.createHeader = function (config) {
+    sf.assert(config, 'createHeader(config) requires a configuration object');
+    sf.assert(!config.columns || Array.isArray(config.columns), 'createHeader(config.columns) expects an array');
+
     var labelWidth = config.labelWidth || 200;
     var columns = config.columns || [];
 
@@ -1071,6 +1125,8 @@ const SF = (function () {
   };
 
   sf.rail.createCard = function (config) {
+    sf.assert(config, 'createCard(config) requires a configuration object');
+
     var labelWidth = config.labelWidth || 200;
     var card = sf.el('div', { className: 'sf-resource-card' });
 
@@ -1175,6 +1231,10 @@ const SF = (function () {
   };
 
   sf.rail.addBlock = function (rail, config) {
+    sf.assert(rail, 'addBlock(rail) requires a rail element');
+    sf.assert(config && config.horizon != null, 'addBlock(config.horizon) is required');
+    sf.assert(config.start != null && config.end != null, 'addBlock(config.start/config.end) are required');
+
     var horizon = config.horizon || 1;
     var startPct = (config.start / horizon) * 100;
     var widthPct = ((config.end - config.start) / horizon) * 100;
@@ -1214,6 +1274,10 @@ const SF = (function () {
   };
 
   sf.rail.addChangeover = function (rail, config) {
+    sf.assert(rail, 'addChangeover(rail) requires a rail element');
+    sf.assert(config && config.horizon != null, 'addChangeover(config.horizon) is required');
+    sf.assert(config.start != null && config.end != null, 'addChangeover(config.start/config.end) are required');
+
     var horizon = config.horizon || 1;
     var startPct = (config.start / horizon) * 100;
     var widthPct = ((config.end - config.start) / horizon) * 100;
@@ -1237,6 +1301,7 @@ const SF = (function () {
   sf.gantt = {};
 
   sf.gantt.create = function (config) {
+    config = config || {};
     var instanceId = sf.uid('sf-gantt');
     var chartPaneId = config.chartPane || (instanceId + '-chart-pane');
     var gridPaneId = config.gridPane || (instanceId + '-grid-pane');
@@ -1306,12 +1371,15 @@ const SF = (function () {
     var ctrl = { el: wrapper };
 
     ctrl.mount = function (parent) {
+      sf.assert(parent, 'gantt.mount(parent) requires a mount target');
       var target = typeof parent === 'string' ? document.getElementById(parent) : parent;
+      sf.assert(target, 'gantt.mount(parent) target not found: ' + parent);
       target.appendChild(wrapper);
       initSplit();
     };
 
     ctrl.setTasks = function (newTasks) {
+      sf.assert(Array.isArray(newTasks), 'gantt.setTasks(tasks) expects an array');
       tasks = newTasks;
       renderGrid(newTasks);
       renderChart(newTasks);
diff --git a/tests/backend-contract.test.js b/tests/backend-contract.test.js
index 6bbd605..f15a940 100644
--- a/tests/backend-contract.test.js
+++ b/tests/backend-contract.test.js
@@ -64,6 +64,31 @@ test('tauri createSchedule normalizes object and numeric ids to strings', async
   assert.equal(await backendWithNumber.createSchedule({}), '7');
 });
 
+test('non-tauri backend labels still use the generic HTTP adapter', async () => {
+  const fetchCalls = [];
+  const { SF } = loadSf(['js-src/00-core.js', 'js-src/10-backend.js'], {
+    fetch(url, opts) {
+      fetchCalls.push({ url, opts });
+      return Promise.resolve({
+        ok: true,
+        headers: { get() { return 'application/json'; } },
+        json() { return Promise.resolve({ id: 'job-9' }); },
+      });
+    },
+  });
+
+  const backend = SF.createBackend({
+    type: 'rails',
+    baseUrl: '/api',
+    schedulesPath: '/jobs',
+  });
+
+  assert.equal(await backend.createSchedule({ foo: 'bar' }), 'job-9');
+  assert.equal(fetchCalls.length, 1);
+  assert.equal(fetchCalls[0].url, '/api/jobs');
+  assert.equal(fetchCalls[0].opts.method, 'POST');
+});
+
 test('tauri streamEvents keeps id-less updates and filters mismatched job ids', async () => {
   let handler = null;
   const received = [];
diff --git a/tests/instance-local-dom.test.js b/tests/instance-local-dom.test.js
index 55fe140..8c7ee8d 100644
--- a/tests/instance-local-dom.test.js
+++ b/tests/instance-local-dom.test.js
@@ -145,3 +145,16 @@ test('gantt instances get unique generated IDs by default', () => {
   assert.equal(onePanes[1].id === twoPanes[1].id, false);
   assert.equal(oneContainer.id === twoContainer.id, false);
 });
+
+test('gantt.create falls back to built-in defaults when config is omitted', () => {
+  const { SF } = loadSf(['js-src/00-core.js', 'js-src/14-gantt.js']);
+
+  const gantt = SF.gantt.create();
+  const panes = gantt.el.querySelectorAll('.sf-gantt-pane');
+  const chartContainer = gantt.el.querySelector('.sf-gantt-container');
+
+  assert.equal(panes.length, 2);
+  assert.equal(Boolean(panes[0].id), true);
+  assert.equal(Boolean(panes[1].id), true);
+  assert.equal(Boolean(chartContainer.id), true);
+});