fix: toHaveTextContent("") causing false positive (#138)

* throw when matching against empty string sugget toBeEmpty

fix #104

* allow empty content to match empty string

Author: kandros

src/__tests__/to-have-text-content.js

@@ -82,4 +82,13 @@ describe('.toHaveTextContent', () => {
       'sensitive text',
     )
   })
+
+  test('when matching with empty string and element with content suggest using toBeEmpty instead', () => {
+    // https://github.com/testing-library/jest-dom/issues/104
+    const {container} = render('<span>not empty</span>')
+
+    expect(() =>
+      expect(container.querySelector('span')).toHaveTextContent(''),
+    ).toThrowError(/toBeEmpty()/)
+  })
 })

src/to-have-text-content.js

@@ -12,8 +12,10 @@ export function toHaveTextContent(
     ? normalize(htmlElement.textContent)
     : htmlElement.textContent.replace(/\u00a0/g, ' ') // Replace   with normal spaces
 
+  const checkingWithEmptyString = textContent !== '' && checkWith === ''
+
   return {
-    pass: matches(textContent, checkWith),
+    pass: !checkingWithEmptyString && matches(textContent, checkWith),
     message: () => {
       const to = this.isNot ? 'not to' : 'to'
       return getMessage(
@@ -22,7 +24,9 @@ export function toHaveTextContent(
           'element',
           '',
         ),
-        `Expected element ${to} have text content`,
+        checkingWithEmptyString
+          ? `Checking with empty string will always match, use .toBeEmpty() instead`
+          : `Expected element ${to} have text content`,
         checkWith,
         'Received',
         textContent,