diff --git a/apps/server/src/modules/school/domain/do/school.spec.ts b/apps/server/src/modules/school/domain/do/school.spec.ts
new file mode 100644
index 00000000000..b7e9c07e51b
--- /dev/null
+++ b/apps/server/src/modules/school/domain/do/school.spec.ts
@@ -0,0 +1,78 @@
+import { schoolFactory } from '../testing';
+import { SchoolFeature } from '../type';
+
+describe('School', () => {
+	describe('addFeature', () => {
+		it('should add the given feature to the features set', () => {
+			const school = schoolFactory.build();
+
+			school.addFeature('test feature' as SchoolFeature);
+
+			expect(school.getProps().features).toContain('test feature');
+		});
+	});
+
+	describe('removeFeature', () => {
+		it('should remove the given feature from the features set', () => {
+			const feature = 'test feature' as SchoolFeature;
+
+			const school = schoolFactory.build({
+				features: new Set([feature]),
+			});
+
+			school.removeFeature(feature);
+
+			expect(school.getProps().features).not.toContain('test feature');
+		});
+	});
+
+	describe('isInMaintenance', () => {
+		it('should return true if inMaintenanceSince is in the past', () => {
+			const school = schoolFactory.build({
+				inMaintenanceSince: new Date('2020-01-01'),
+			});
+
+			const result = school.isInMaintenance();
+
+			expect(result).toBe(true);
+		});
+
+		it('should return false if inMaintenanceSince is in the future', () => {
+			const school = schoolFactory.build({
+				inMaintenanceSince: new Date('2100-01-01'),
+			});
+
+			const result = school.isInMaintenance();
+
+			expect(result).toBe(false);
+		});
+
+		it('should return false if inMaintenanceSince is undefined', () => {
+			const school = schoolFactory.build();
+
+			const result = school.isInMaintenance();
+
+			expect(result).toBe(false);
+		});
+	});
+
+	describe('isExternal', () => {
+		it('should return true if externalId is set', () => {
+			const school = schoolFactory.build({
+				externalId: 'test',
+			});
+
+			const result = school.isExternal();
+
+			expect(result).toBe(true);
+		});
+
+		it('should return false if externalId is undefined', () => {
+			const school = schoolFactory.build();
+
+			const result = school.isExternal();
+
+			expect(result).toBe(false);
+		});
+	});
+});