Revert "Support searching for a plain text string in to contain"

This reverts commit d586657.

documentation/assertions/DOMElement/to-contain.md

@@ -21,13 +21,7 @@ string:
 expect(element, 'to contain', '<h1>Assert on text content</h1>');
 ```
 
-You can also assert that the element contains a given text node:
-
-```js
-expect(element, 'to contain', 'Assert on text content');
-```
-
-Or you can also assert against a DOM element:
+You can also assert against a DOM element:
 
 ```js
 expect(element, 'to contain', createElement('<h1>Assert on text content</h1>'));

src/index.js

@@ -1651,15 +1651,15 @@ module.exports = {
           );
 
           if (typeof spec === 'string') {
-            spec = {
-              textContent: spec
-            };
-          } else {
-            ensureSupportedSpecOptions(spec);
-
-            expect.argsOutput = output =>
-              output.appendInspected(documentFragment.childNodes[0]);
+            throw new Error(
+              'HTMLElement to contain string: please provide a HTML structure as a string'
+            );
           }
+
+          expect.argsOutput = output =>
+            output.appendInspected(documentFragment.childNodes[0]);
+
+          ensureSupportedSpecOptions(spec);
         }
 
         const scoredElements = findMatchesWithGoodScore(nodes, spec);

test/index.spec.js

@@ -3158,12 +3158,18 @@ describe('unexpected-dom', () => {
       );
     });
 
-    it('supports searching for a plain string', () => {
+    it('fails searching for a plain string', () => {
       expect(
-        '<div><span class="greeting"><span>Hello</span><span class="name">Jane Doe</span></span></div>',
-        'when parsed as HTML',
-        'to contain',
-        'Jane Doe'
+        () => {
+          expect(
+            '<div><span class="greeting"><span>Hello</span><span class="name">Jane Doe</span></span></div>',
+            'when parsed as HTML',
+            'to contain',
+            'Jane Doe'
+          );
+        },
+        'to throw',
+        'HTMLElement to contain string: please provide a HTML structure as a string'
       );
     });