From 716a7d483da73e3ed4d1f9d19ded1c6d7bc3eda1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mario=20Beltra=CC=81n=20Alarco=CC=81n?= <belco90@gmail.com>
Date: Fri, 2 Aug 2019 16:01:08 +0200
Subject: [PATCH] Add useSetState tests

---
 src/__tests__/useSetState.test.ts | 42 +++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)
 create mode 100644 src/__tests__/useSetState.test.ts

diff --git a/src/__tests__/useSetState.test.ts b/src/__tests__/useSetState.test.ts
new file mode 100644
index 00000000..684ba30b
--- /dev/null
+++ b/src/__tests__/useSetState.test.ts
@@ -0,0 +1,42 @@
+import { act, renderHook } from '@testing-library/react-hooks';
+import useSetState from '../useSetState';
+
+const setUp = (initialState?: object) => renderHook(() => useSetState(initialState));
+
+it('should init state and setter', () => {
+  const { result } = setUp({ foo: 'bar' });
+  const [state, setState] = result.current;
+
+  expect(state).toEqual({ foo: 'bar' });
+  expect(setState).toBeInstanceOf(Function);
+});
+
+it('should init empty state if not initial state provided', () => {
+  const { result } = setUp();
+
+  expect(result.current[0]).toEqual({});
+});
+
+it('should merge changes into current state when providing object', () => {
+  const { result } = setUp({ foo: 'bar', count: 1 });
+  const [state, setState] = result.current;
+
+  act(() => {
+    // @ts-ignore
+    setState({ count: state.count + 1, someBool: true });
+  });
+
+  expect(result.current[0]).toEqual({ foo: 'bar', count: 2, someBool: true });
+});
+
+it('should merge changes into current state when providing function', () => {
+  const { result } = setUp({ foo: 'bar', count: 1 });
+  const [, setState] = result.current;
+
+  act(() => {
+    // @ts-ignore
+    setState(prevState => ({ count: prevState.count + 1, someBool: true }));
+  });
+
+  expect(result.current[0]).toEqual({ foo: 'bar', count: 2, someBool: true });
+});