From 67ec4d3a29d6907ba84a8bfafbffe80e4f58b349 Mon Sep 17 00:00:00 2001
From: Sune Simonsen <sune@we-knowhow.dk>
Date: Tue, 26 Feb 2019 09:19:15 +0100
Subject: [PATCH] Don't allow to contain to match directly on the subject

---
 .../assertions/DOMElement/to-contain.md       |  2 +-
 src/index.js                                  |  7 +++--
 test/index.spec.js                            | 26 +++++++++++++++++++
 3 files changed, 30 insertions(+), 5 deletions(-)

diff --git a/documentation/assertions/DOMElement/to-contain.md b/documentation/assertions/DOMElement/to-contain.md
index 5d8cdbd3..e2699d15 100644
--- a/documentation/assertions/DOMElement/to-contain.md
+++ b/documentation/assertions/DOMElement/to-contain.md
@@ -1,4 +1,4 @@
-Assert that an element contains elements satisfying a given specification.
+Assert that an element contains descendant elements satisfying a given specification.
 
 ```js
 var element = createElement(`
diff --git a/src/index.js b/src/index.js
index 9bbfba8f..24218179 100644
--- a/src/index.js
+++ b/src/index.js
@@ -1625,9 +1625,8 @@ module.exports = {
     expect.exportAssertion(
       '<DOMDocument|DOMElement|DOMDocumentFragment|DOMNodeList> to contain <DOMElement|object|string>',
       (expect, subject, value) => {
-        const isHtml = isInsideHtmlDocument(
-          typeof subject.length === 'number' ? subject[0] : subject
-        );
+        const nodes = subject.childNodes || subject;
+        const isHtml = isInsideHtmlDocument(nodes[0]);
         const valueType = expect.findTypeOf(value);
         let spec = value;
 
@@ -1652,7 +1651,7 @@ module.exports = {
 
         ensureSupportedSpecOptions(spec);
 
-        const scoredElements = findMatchesWithGoodScore(subject, spec);
+        const scoredElements = findMatchesWithGoodScore(nodes, spec);
 
         if (scoredElements.length === 0) {
           expect.subjectOutput = output =>
diff --git a/test/index.spec.js b/test/index.spec.js
index ac572195..dcb2f691 100644
--- a/test/index.spec.js
+++ b/test/index.spec.js
@@ -3147,6 +3147,32 @@ describe('unexpected-dom', () => {
       );
     });
 
+    it('should not match directly on the subject', () => {
+      expect(
+        () => {
+          expect(
+            parseHtmlNode(
+              '<span class="greeting"><span>Hello</span><span class="name">Jane Doe</span></span>'
+            ),
+            'to contain',
+            '<span><span>Hello</span><!--ignore--></span>'
+          );
+        },
+        'to throw',
+        'expected\n' +
+          '<span class="greeting">\n' +
+          '  <span>Hello</span>\n' +
+          '  <span class="name">Jane Doe</span>\n' +
+          '</span>\n' +
+          "to contain '<span><span>Hello</span><!--ignore--></span>'\n" +
+          '\n' +
+          '<span>\n' +
+          "  // missing { name: 'span', attributes: {}, children: [ 'Hello' ] }\n" +
+          '  Hello\n' +
+          '</span>'
+      );
+    });
+
     it('fails without a diff if no good candidates can be found in the given structure', () => {
       expect(
         () => {