diff --git a/app/data/ct.libs/assert/AssertYield.png b/app/data/ct.libs/assert/AssertYield.png
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diff --git a/app/data/ct.libs/assert/README.md b/app/data/ct.libs/assert/README.md
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+A tiny module that provides a method `ct.assert(condition, message)` to help making readable tests in ct.js projects.
+
+The `condition` may be either boolean or a function — other values (numbers, strings) will fail. Functions are executed first and then tested against their returned result.
+
+There is also a `ct.assert.summary();` call, that shows counted amount of passed and failed tests.
+
+Usage example:
+
+```js
+ct.assert(
+    ct.inherit.isParent('AbstractMonster', 'Monster_Red_Squished'),
+    'ct.inherit.isParent works with two types (two strings)'
+);
+ct.assert(
+    ct.inherit.isChild('Monster_Green', 'AbstractMonster'),
+    'ct.inherit.isChild works with two types (two strings)'
+);
+ct.assert(
+    ct.inherit.list('AbstractMonster').length === 2,
+    'ct.inherit.list gets all the monsters'
+);
+ct.assert(
+    ct.inherit.isChild(ct.types.list['Monster_Green'][0], 'AbstractMonster'),
+    'ct.inherit.isChild works against a copy and a type'
+);
+ct.assert(
+    ct.inherit.isChild(ct.types.list['Monster_Red_Squished'][0], ct.types.list['Monster_Red'][0]),
+    'ct.inherit.isChild works against two copies'
+);
+ct.assert.summary();
+```
+
+This will yield:
+
+![](./data/ct.libs/assert/AssertYield.png)
+
+## Grouping results and measuring time
+
+You still have all the powers of browser's asserting and logging tools.
+
+If you want to group test results, use `console.group('Label');` and `console.groupEnd();`.
+
+If you want to measure the amount of time somethign takes to compute, use `console.time('Label')`; and `console.timeEnd('Label');`.
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diff --git a/app/data/ct.libs/assert/index.js b/app/data/ct.libs/assert/index.js
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+{
+    let passed = 0,
+        failed = 0;
+    ct.assert = function assert(condition, message) {
+        let result = condition;
+        if (condition instanceof Function) {
+            try {
+                result = condition();
+            } catch (e) {
+                console.error(`%c Got an execution error while evaluating%c${message ? ':\n' + message : ''}`, 'font-weigth: bold;', '');
+                failed++;
+                throw e;
+            }
+        }
+        if (typeof result !== 'boolean') {
+            console.error(`%c Not a boolean%c${message ? ':\n' + message : ''}\nGot this value:`, 'font-weigth: bold;', '');
+            // eslint-disable-next-line no-console
+            console.log(result);
+            failed++;
+        }
+        if (result) {
+            // eslint-disable-next-line no-console
+            console.log(`%c✅ Passed%c${message ? ':\n' + message : ''}`, 'color: #3c3; font-weight: bold;', '');
+            passed++;
+        } else {
+            console.error(`%c Failed%c${message ? ':\n' + message : ''}`, 'font-weigth: bold;', '');
+            failed++;
+        }
+    };
+    ct.assert.summary = function summary() {
+        if (failed > 0) {
+            console.error(`%c Failed: ${failed}, passed: ${passed}.`, 'font-weight: bold;');
+        } else {
+            // eslint-disable-next-line no-console
+            console.log(`%c✅ Failed: ${failed}, passed: ${passed}.`, 'color: #3c3; font-weight: bold;');
+        }
+        failed = passed = 0;
+    };
+}
diff --git a/app/data/ct.libs/assert/module.json b/app/data/ct.libs/assert/module.json
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+++ b/app/data/ct.libs/assert/module.json
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+{
+  "main": {
+    "name": "ct.assert",
+    "version": "1.0.0",
+    "packageName": "assert",
+    "authors": [{
+      "name": "Comigo",
+      "mail": "admin@nersta.ru"
+    }]
+  }
+}
diff --git a/app/data/ct.libs/assert/types.d.ts b/app/data/ct.libs/assert/types.d.ts
new file mode 100644
index 000000000..704bc4126
--- /dev/null
+++ b/app/data/ct.libs/assert/types.d.ts
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+declare namespace ct {
+    /**
+     * A tiny module to simplify tests in ct.js projects.
+     * @param condition may be either boolean or a function — other values (numbers, strings) will fail. Functions are executed first and then tested against their returned result.
+     * @param message The message to show in console.
+     */
+    function assert(condition: boolean | Function, message: string): void;
+
+    namespace assert {
+        /**
+         * Displays a summary with a number of failed and passed tasks, and resets the counter of failed and passed tasks.
+         */
+        function summary(): void;
+    }
+}
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