add some basic testing for useAsync

package.json

@@ -55,15 +55,29 @@
     "singleQuote": true,
     "trailingComma": "es5"
   },
+  "jest": {
+    "globals": {
+      "ts-jest": {
+        "tsConfig": "tsconfig.test.json"
+      }
+    },
+    "setupFilesAfterEnv": [
+      "@testing-library/jest-dom/extend-expect"
+    ]
+  },
   "devDependencies": {
+    "@testing-library/jest-dom": "^4.1.2",
+    "@testing-library/react": "^9.3.0",
+    "@testing-library/react-hooks": "^3.1.0",
     "@types/jest": "^24.0.12",
-    "@types/react": "^16.8.16",
-    "@types/react-dom": "^16.8.4",
+    "@types/react": "^16.9.9",
+    "@types/react-dom": "^16.9.2",
     "husky": "^2.2.0",
     "prettier": "^1.17.0",
     "pretty-quick": "^1.10.0",
-    "react": "^16.8.6",
-    "react-dom": "^16.8.6",
+    "react": "^16.10.2",
+    "react-dom": "^16.10.2",
+    "react-test-renderer": "^16.10.2",
     "tsdx": "^0.7.2",
     "tslib": "^1.9.3",
     "typescript": "^3.4.5"

test/useAsync.test.ts

@@ -0,0 +1,75 @@
+import { useAsync } from '../src';
+import { renderHook } from '@testing-library/react-hooks';
+
+interface StarwarsHero {
+  name: string;
+}
+
+export const generateMockResponseData = (amount: number = 5): StarwarsHero[] =>
+  [...Array(amount).keys()].map(n => ({
+    id: n + 1,
+    name: `Starwars Hero ${n + 1}`,
+  }));
+
+describe('useAync', () => {
+  const fakeResults = generateMockResponseData();
+
+  it('should have a useAsync hook', () => {
+    expect(useAsync).toBeDefined();
+  });
+
+  it('should resolve a successful request', async () => {
+    const onSuccess = jest.fn();
+    const onError = jest.fn();
+
+    const { result, waitForNextUpdate } = renderHook(() =>
+      useAsync(
+        async () => {
+          return Promise.resolve(fakeResults);
+        },
+        [],
+        {
+          onSuccess: () => onSuccess(),
+          onError: () => onError(),
+        }
+      )
+    );
+
+    expect(result.current.loading).toBe(true);
+
+    await waitForNextUpdate();
+
+    expect(result.current.result).toEqual(fakeResults);
+    expect(result.current.loading).toBe(false);
+    expect(result.current.error).toBeUndefined();
+    expect(onSuccess).toHaveBeenCalled();
+    expect(onError).not.toHaveBeenCalled();
+  });
+
+  it('should set error detail for unsuccessful request', async () => {
+    const onSuccess = jest.fn();
+    const onError = jest.fn();
+
+    const { result, waitForNextUpdate } = renderHook(() =>
+      useAsync(
+        async () => {
+          throw new Error('something went wrong');
+        },
+        [],
+        {
+          onSuccess: () => onSuccess(),
+          onError: () => onError(),
+        }
+      )
+    );
+
+    await waitForNextUpdate();
+
+    expect(result.current.error).toBeDefined();
+    expect(result.current.error!.message).toBe('something went wrong');
+    expect(result.current.loading).toBe(false);
+    expect(result.current.result).toBeUndefined();
+    expect(onSuccess).not.toHaveBeenCalled();
+    expect(onError).toHaveBeenCalled();
+  });
+});

tsconfig.json

@@ -1,5 +1,6 @@
 {
   "include": ["src", "types"],
+  "exclude": ["test"],
   "compilerOptions": {
     "target": "es5",
     "module": "esnext",

tsconfig.test.json

@@ -0,0 +1,7 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "downlevelIteration": true
+  },
+  "include": ["src/**/*.ts", "test/**/*.ts"]
+}