Add some tests for Result

src/Result.test.ts

@@ -0,0 +1,41 @@
+import { failure, success } from './Result';
+
+describe('Success', () => {
+	it('should be a success', () => {
+		const s = success(123);
+		expect(s.isSuccess()).toBe(true);
+	});
+
+	it('should be no failure', () => {
+		const s = success(123);
+		expect(s.isFailure()).toBe(false);
+	});
+
+	it('should apply map', () => {
+		const s = success(123);
+		const mapped = s.map((x) => x > 5);
+		expect(mapped.isSuccess()).toBe(true);
+		expect(mapped.getUnsafe()).toBe(true);
+	});
+});
+
+describe('Failure', () => {
+	it('should be a failure', () => {
+		const f = failure('failure');
+		expect(f.isSuccess()).toBe(false);
+	});
+
+	it('should be no success', () => {
+		const f = failure('failure');
+		expect(f.isFailure()).toBe(true);
+	});
+
+	it('should apply map', () => {
+		const f = failure('failure');
+		const mapped = f.map(() => false);
+		expect(mapped.isSuccess()).toBe(false);
+		expect(() => {
+			mapped.getUnsafe();
+		}).toThrow(Error);
+	});
+});