fix(getByText): support inputs where type is either button or submit (#185)

* Make getByText support inputs where type is either `button` or `submit`

Closes testing-library/react-testing-library#248

* change quotes

Author: julienw

README.md

@@ -296,6 +296,14 @@ matching the given [`TextMatch`](#textmatch).
 const aboutAnchorNode = getByText(container, /about/i)
 ```
 
+It also works properly with `input`s whose `type` attribute is either `submit`
+or `button`:
+
+```javascript
+// <input type="submit" value="Send data" />
+const submitButton = getByText(container, /send data/i)
+```
+
 > NOTE: see [`getByLabelText`](#getbylabeltext) for more details on how and when to use the `selector` option
 
 The `ignore` option accepts a query selector. If the
@@ -702,6 +710,17 @@ This function is also used internally when querying nodes by their text content.
 This enables functions like `getByText` and `queryByText` to work as expected,
 finding elements in the DOM similarly to how users would do.
 
+The function has a special behavior for some input elements:
+
+```javascript
+// <input type="submit" value="Send data" />
+// <input type="button" value="Push me" />
+const submitText = getNodeText(container.querySelector('input[type=submit]')) // "Send data"
+const buttonText = getNodeText(container.querySelector('input[type=button]')) // "Push me"
+
+These elements use the attribute `value` and display its value to the user.
+```
+
 ## Custom Jest Matchers
 
 When using [jest][], it is convenient to import a set of custom matchers that

src/__tests__/element-queries.js

@@ -76,6 +76,19 @@ test('can get elements by matching their text across adjacent text nodes', () =>
   expect(queryByText('£24.99')).toBeTruthy()
 })
 
+test('can get input elements with type submit or button', () => {
+  const {queryByText} = render(`
+    <div>
+      <input type="submit" value="Send data"/>
+      <input type="button" value="Push me!"/>
+      <input type="text" value="user data" />
+    </div>
+  `)
+  expect(queryByText('Send data')).toBeTruthy()
+  expect(queryByText('Push me!')).toBeTruthy()
+  expect(queryByText('user data')).toBeFalsy()
+})
+
 test('matches case with RegExp matcher', () => {
   const {queryByText} = render(`
     <span>STEP 1 of 4</span>

src/get-node-text.js

@@ -1,6 +1,10 @@
 function getNodeText(node) {
   const window = node.ownerDocument.defaultView
 
+  if (node.matches('input[type=submit], input[type=button]')) {
+    return node.value;
+  }
+
   return Array.from(node.childNodes)
     .filter(
       child =>