test: harden business boundary conditions

apps/server/src/classes/classes.boundaries.spec.ts

@@ -0,0 +1,69 @@
+import { BadRequestException, NotFoundException } from '@nestjs/common';
+import { ClassesService } from './classes.service';
+
+function createService(classRepo: Record<string, jest.Mock>, classTeacherRepo = {}) {
+  return new ClassesService(
+    classRepo as never,
+    {} as never,
+    classTeacherRepo as never,
+    {} as never,
+    {} as never,
+    {} as never,
+    {} as never,
+    {} as never,
+  );
+}
+
+describe('ClassesService — archive and teacher boundaries', () => {
+  it('rejects repeated archive and restore operations', async () => {
+    await expect(
+      createService({ findOne: jest.fn().mockResolvedValue({ isArchived: true }) }).archive(1),
+    ).rejects.toBeInstanceOf(BadRequestException);
+    await expect(
+      createService({ findOne: jest.fn().mockResolvedValue({ isArchived: false }) }).restore(1),
+    ).rejects.toBeInstanceOf(BadRequestException);
+  });
+
+  it('rejects assigning a teacher to a missing class', async () => {
+    const classTeacherRepo = { findOne: jest.fn(), create: jest.fn(), save: jest.fn() };
+    await expect(
+      createService({ findOne: jest.fn().mockResolvedValue(null) }, classTeacherRepo).addTeacher(
+        9,
+        {
+          userId: 2,
+          roleType: 'head_teacher',
+        },
+      ),
+    ).rejects.toBeInstanceOf(NotFoundException);
+    expect(classTeacherRepo.save).not.toHaveBeenCalled();
+  });
+
+  it('rejects duplicate teacher roles', async () => {
+    const classTeacherRepo = {
+      findOne: jest.fn().mockResolvedValue({ id: 3 }),
+      create: jest.fn(),
+      save: jest.fn(),
+    };
+    await expect(
+      createService(
+        { findOne: jest.fn().mockResolvedValue({ id: 1 }) },
+        classTeacherRepo,
+      ).addTeacher(1, {
+        userId: 2,
+        roleType: 'head_teacher',
+      }),
+    ).rejects.toBeInstanceOf(BadRequestException);
+  });
+
+  it('rejects removing a teacher or assignment that is not in the class', async () => {
+    const classTeacherRepo = {
+      find: jest.fn().mockResolvedValue([]),
+      findOne: jest.fn().mockResolvedValue(null),
+      delete: jest.fn(),
+    };
+    const service = createService({}, classTeacherRepo);
+    await expect(service.removeTeacher(1, 2)).rejects.toBeInstanceOf(NotFoundException);
+    await expect(service.removeTeacherAssignment(1, 3)).rejects.toBeInstanceOf(NotFoundException);
+    expect(classTeacherRepo.delete).not.toHaveBeenCalled();
+  });
+});