From 6ff06e6392ecef8da941f6b9ccc4432b603f8c9c Mon Sep 17 00:00:00 2001
From: Sebastian Good <git@scagood.co.uk>
Date: Mon, 26 Oct 2020 20:02:43 +0000
Subject: [PATCH 1/2] Add tests that will fail

---
 .../expect/src/__tests__/asymmetricMatchers.test.ts   | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/packages/expect/src/__tests__/asymmetricMatchers.test.ts b/packages/expect/src/__tests__/asymmetricMatchers.test.ts
index dac1a7c1b804..843e51b8719c 100644
--- a/packages/expect/src/__tests__/asymmetricMatchers.test.ts
+++ b/packages/expect/src/__tests__/asymmetricMatchers.test.ts
@@ -169,6 +169,17 @@ test('ObjectContaining matches', () => {
     objectContaining({first: objectContaining({second: {}})}).asymmetricMatch({
       first: {second: {}},
     }),
+    objectContaining({foo: Buffer.from('foo')}).asymmetricMatch({
+      foo: Buffer.from('foo'),
+      jest: 'jest',
+    }),
+    objectContaining({foo: {bar: [Buffer.from('foo')]}}).asymmetricMatch({
+      foo: {
+        bar: [Buffer.from('foo'), 1],
+        qux: 'qux',
+      },
+      jest: 'jest',
+    }),
   ].forEach(test => {
     jestExpect(test).toEqual(true);
   });

From c523b65b58fc31681c28fa3a7cc27fbcbfe3c89b Mon Sep 17 00:00:00 2001
From: Sebastian Good <git@scagood.co.uk>
Date: Mon, 26 Oct 2020 20:04:45 +0000
Subject: [PATCH 2/2] Resolve stepping into non vanilla objects

---
 packages/expect/src/asymmetricMatchers.ts | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/packages/expect/src/asymmetricMatchers.ts b/packages/expect/src/asymmetricMatchers.ts
index 280ebc9d5fe2..86db22aac4fe 100644
--- a/packages/expect/src/asymmetricMatchers.ts
+++ b/packages/expect/src/asymmetricMatchers.ts
@@ -178,11 +178,21 @@ class ObjectContaining extends AsymmetricMatcher<Record<string, unknown>> {
       return true;
     } else {
       for (const property in this.sample) {
-        const expected =
-          typeof this.sample[property] === 'object' &&
-          !(this.sample[property] instanceof AsymmetricMatcher)
-            ? objectContaining(this.sample[property] as Record<string, unknown>)
-            : this.sample[property];
+        let expected = this.sample[property];
+
+        if (typeof this.sample[property] === 'object') {
+          const samplePropertyPrototype = Object.getPrototypeOf(
+            this.sample[property],
+          );
+          if (
+            samplePropertyPrototype === Object.prototype ||
+            samplePropertyPrototype === Array.prototype
+          ) {
+            expected = objectContaining(
+              this.sample[property] as Record<string, unknown>,
+            );
+          }
+        }
 
         if (
           !hasProperty(other, property) ||