test(NotificationModel-type-compiler): verify TypeScript Compiler Validation & Schema Constraints Stability (Variation 10) (JhaSourav07#3103)

## Description

Fixes JhaSourav07#2902 

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closes JhaSourav07#2902

Author: JhaSourav07

models/Notification.type-compiler.test.ts

@@ -0,0 +1,64 @@
+import { describe, it, expect, expectTypeOf } from 'vitest';
+import { INotification, Notification } from './Notification';
+import { Document } from 'mongoose';
+
+describe('Notification.ts - TypeScript Compiler Validation & Schema Constraints Stability', () => {
+  it('Import the interfaces, types, or validation schemas associated with the file.', () => {
+    // 1st condition: Ensure types and schemas are importable
+    expect(Notification).toBeDefined();
+    // Simply asserting that the exported mongoose Model exists and is a valid constructor
+    expect(typeof Notification).toBe('function');
+  });
+
+  it('Use type-testing assertions (expectTypeOf) to enforce field property configurations.', () => {
+    // 2nd condition: Enforce field properties via vitest's expectTypeOf
+    // This is largely a compile-time check but works in vitest runners natively.
+    expectTypeOf<INotification>().toHaveProperty('username').toBeString();
+    expectTypeOf<INotification>().toHaveProperty('email').toBeString();
+    expectTypeOf<INotification>().toHaveProperty('notifyOnCommit').toBeBoolean();
+    expectTypeOf<INotification>().toHaveProperty('createdAt').toEqualTypeOf<Date>();
+  });
+
+  it('Assert that invalid prop parameters are blocked during static type checking.', () => {
+    // 3rd condition: Block invalid props (runtime mongoose schematic equivalent verification)
+    const invalidDoc = new Notification({
+      username: 'testuser',
+      // Intentionally omitting required 'email'
+    });
+
+    // Mongoose synchronusly validates and returns an error for invalid constraints
+    const validationError = invalidDoc.validateSync();
+    expect(validationError).toBeDefined();
+    expect(validationError!.errors.email.name).toBe('ValidatorError');
+    expect(validationError!.errors.email.kind).toBe('required');
+  });
+
+  it('Verify custom types accept optional values without compile errors.', () => {
+    // 4th condition: Verify standard TS partiality/optional values
+    // Using TS standard utility types to confirm flexible compatibility
+    type OptionalNotification = Partial<INotification>;
+
+    // Testing object declaration won't fail static compile
+    const strictlyPartialData: OptionalNotification = {
+      email: 'partial@example.com',
+    };
+
+    expectTypeOf(strictlyPartialData).toMatchTypeOf<Partial<INotification>>();
+    expect(strictlyPartialData.email).toBe('partial@example.com');
+    expect(strictlyPartialData.username).toBeUndefined(); // strictly isolated optional value
+  });
+
+  it('Verify schema validation constraints return strict validation reports.', () => {
+    // 5th condition: Schema constraints returning strict reporting objects
+    const docWithInvalidEnum = new Notification({
+      username: 'test',
+      email: 'test@example.com',
+      frequency: 'not-a-valid-frequency', // Must be 'realtime' | 'daily' | 'weekly'
+    });
+
+    const errorReport = docWithInvalidEnum.validateSync();
+    expect(errorReport).toBeDefined();
+    expect(errorReport!.errors.frequency).toBeDefined();
+    expect(errorReport!.errors.frequency.kind).toBe('enum');
+  });
+});