Feature/add tests

.babelrc

@@ -11,11 +11,7 @@
     ],
     "@babel/preset-react"
   ],
-  "env": {
-    "test": {
-      "plugins": ["@babel/plugin-transform-react-jsx-source", "istanbul"]
-    }
-  },
+
   "plugins": [
     "@babel/plugin-syntax-dynamic-import",
     "@babel/plugin-syntax-import-meta",

package-scripts.js

@@ -6,6 +6,10 @@ const rimraf = npsUtils.rimraf
 
 module.exports = {
   scripts: {
+    test: {
+      default: 'jest --coverage',
+      watch: 'jest --coverage --watch'
+    },
     size: {
       description: 'check the size of the bundle',
       script: 'bundlesize'

package.json

@@ -12,6 +12,7 @@
   ],
   "scripts": {
     "start": "nps",
+    "test": "nps test",
     "doctoc": "doctoc README.md && doctoc docs/faq.md && prettier --write README.md && prettier --write docs/faq.md",
     "precommit": "lint-staged && npm start validate",
     "prepublish": "npm start validate",
@@ -69,6 +70,7 @@
     "prop-types": "^15.6.2",
     "react": "^16.8.1",
     "react-dom": "^16.8.1",
+    "react-hooks-testing-library": "^0.4.0",
     "rollup": "^1.1.2",
     "rollup-plugin-babel": "^4.0.1",
     "rollup-plugin-commonjs": "^9.2.0",

src/useField.test.js

@@ -0,0 +1,157 @@
+import { renderHook, cleanup } from 'react-hooks-testing-library'
+import useField, { all } from './useField'
+
+describe('useField()', () => {
+  let form, name, subscription
+
+  beforeEach(() => {
+    name = 'foo'
+    subscription = { value: true }
+  })
+  afterEach(cleanup)
+
+  describe("form hook parameter's registerField", () => {
+    beforeEach(() => {
+      form = {
+        registerField: jest.fn()
+      }
+    })
+
+    it('is called with correct params', () => {
+      renderHook(() => useField(name, form, subscription))
+
+      expect(form.registerField).toHaveBeenCalledWith(
+        name,
+        expect.any(Function),
+        subscription
+      )
+    })
+
+    it('receives all subscriptions by default', () => {
+      renderHook(() => useField(name, form))
+
+      expect(form.registerField).toHaveBeenCalledWith(
+        name,
+        expect.any(Function),
+        all
+      )
+    })
+  })
+
+  describe('field input props return object', () => {
+    let value, blur, change, focus
+
+    const setupHook = () => {
+      const { result } = renderHook(() => useField(name, form, subscription))
+      const { input } = result.current
+
+      return input
+    }
+
+    beforeEach(() => {
+      value = 'bar'
+      blur = jest.fn()
+      change = jest.fn()
+      focus = jest.fn()
+
+      form = {
+        registerField: jest.fn((name, callback, subscription) =>
+          callback({ blur, change, focus, value })
+        )
+      }
+    })
+
+    it('has the correct name', () => {
+      const { name: returnName } = setupHook()
+
+      expect(returnName).toBe(name)
+    })
+
+    it('has the correct value', () => {
+      const { value: returnValue } = setupHook()
+
+      expect(returnValue).toBe(value)
+    })
+
+    describe('onBlur()', () => {
+      it('calls the correct event handler', () => {
+        const { onBlur } = setupHook()
+
+        onBlur()
+
+        expect(blur).toHaveBeenCalled()
+      })
+    })
+
+    describe('onChange()', () => {
+      describe('when event is not an usual input event', () => {
+        const event = { foo: 'bar' }
+
+        it('calls the provided handler with event object', () => {
+          const { onChange } = setupHook()
+
+          onChange(event)
+
+          expect(change).toHaveBeenCalledWith(event)
+        })
+      })
+
+      describe('when event has a value prop', () => {
+        const event = { target: { value: 'foo' } }
+
+        it('calls provided handler with value', () => {
+          const { onChange } = setupHook()
+
+          onChange(event)
+
+          expect(change).toHaveBeenLastCalledWith(event.target.value)
+        })
+      })
+
+      describe('when event has a checked prop', () => {
+        const event = { target: { type: 'radio', checked: false } }
+
+        it('calls provided handler with value', () => {
+          const { onChange } = setupHook()
+
+          onChange(event)
+
+          expect(change).toHaveBeenLastCalledWith(event.target.checked)
+        })
+      })
+    })
+
+    describe('onFocus()', () => {
+      it('calls the correct event handler', () => {
+        const { onFocus } = setupHook()
+
+        onFocus()
+
+        expect(focus).toHaveBeenCalled()
+      })
+    })
+  })
+
+  describe('field meta return object', () => {
+    let meta
+
+    beforeEach(() => {
+      meta = { name: 'foo', bar: 'bar', biz: 'biz' }
+
+      form = {
+        registerField: jest.fn((name, callback, subscription) =>
+          callback({ ...meta })
+        )
+      }
+    })
+
+    it('has the correct values', () => {
+      const { result } = renderHook(() => useField(name, form, subscription))
+      const { meta: returnMeta } = result.current
+
+      delete meta.name
+
+      expect(returnMeta).toEqual(meta)
+    })
+  })
+})