feat: Add unit tests for backend validators and configure Jest.

Backend/tests/unit/validators/AdminCourseApproval.validator.test.ts

@@ -0,0 +1,67 @@
+import {
+    ApproveCourseValidator,
+    RejectCourseValidator,
+} from '@/validators/AdminCourseApproval.validator';
+
+describe('ApproveCourseValidator', () => {
+    it('should pass with no body (comment optional)', () => {
+        const { error } = ApproveCourseValidator.validate({});
+        expect(error).toBeUndefined();
+    });
+
+    it('should pass with optional comment', () => {
+        const { error } = ApproveCourseValidator.validate({
+            comment: 'Looks great!',
+        });
+        expect(error).toBeUndefined();
+    });
+
+    it('should fail when comment exceeds 1000 characters', () => {
+        const { error } = ApproveCourseValidator.validate({
+            comment: 'a'.repeat(1001),
+        });
+        expect(error).toBeDefined();
+        expect(error?.details[0].message).toMatch(/must not exceed 1000/i);
+    });
+
+    it('should pass with comment exactly 1000 characters', () => {
+        const { error } = ApproveCourseValidator.validate({
+            comment: 'a'.repeat(1000),
+        });
+        expect(error).toBeUndefined();
+    });
+});
+
+describe('RejectCourseValidator', () => {
+    it('should pass with valid rejection comment', () => {
+        const { error } = RejectCourseValidator.validate({
+            comment: 'The content is incomplete and needs more details.',
+        });
+        expect(error).toBeUndefined();
+    });
+
+    it('should fail without comment', () => {
+        const { error } = RejectCourseValidator.validate({});
+        expect(error).toBeDefined();
+        expect(error?.details[0].message).toMatch(/Comment is required when rejecting/i);
+    });
+
+    it('should fail when comment is too short (< 10 chars)', () => {
+        const { error } = RejectCourseValidator.validate({ comment: 'Too short' });
+        expect(error).toBeDefined();
+        expect(error?.details[0].message).toMatch(/at least 10 characters/i);
+    });
+
+    it('should pass with exactly 10 characters', () => {
+        const { error } = RejectCourseValidator.validate({ comment: '1234567890' });
+        expect(error).toBeUndefined();
+    });
+
+    it('should fail when comment exceeds 1000 characters', () => {
+        const { error } = RejectCourseValidator.validate({
+            comment: 'a'.repeat(1001),
+        });
+        expect(error).toBeDefined();
+        expect(error?.details[0].message).toMatch(/must not exceed 1000/i);
+    });
+});