diff --git a/test/integration/full-content/fixtures/core__4-invalid-starting-letter.parsed.json b/test/integration/full-content/fixtures/core__4-invalid-starting-letter.parsed.json
index 8916c77031765..2dfce101b41c9 100644
--- a/test/integration/full-content/fixtures/core__4-invalid-starting-letter.parsed.json
+++ b/test/integration/full-content/fixtures/core__4-invalid-starting-letter.parsed.json
@@ -1,6 +1,8 @@
 [
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "<!-- wp:core/4-invalid /-->\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__audio.parsed.json b/test/integration/full-content/fixtures/core__audio.parsed.json
index d62c5d57261cd..33926c0b889b5 100644
--- a/test/integration/full-content/fixtures/core__audio.parsed.json
+++ b/test/integration/full-content/fixtures/core__audio.parsed.json
@@ -8,7 +8,9 @@
         "innerHTML": "\n<figure class=\"wp-block-audio alignright\">\n    <audio controls=\"\" src=\"https://media.simplecast.com/episodes/audio/80564/draft-podcast-51-livePublish2.mp3\"></audio>\n</figure>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__block.parsed.json b/test/integration/full-content/fixtures/core__block.parsed.json
index d2d112cf29fc6..61b65e317a8e1 100644
--- a/test/integration/full-content/fixtures/core__block.parsed.json
+++ b/test/integration/full-content/fixtures/core__block.parsed.json
@@ -8,7 +8,9 @@
         "innerHTML": ""
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__button__center.parsed.json b/test/integration/full-content/fixtures/core__button__center.parsed.json
index e4f1bd00d126d..0094e8f264073 100644
--- a/test/integration/full-content/fixtures/core__button__center.parsed.json
+++ b/test/integration/full-content/fixtures/core__button__center.parsed.json
@@ -8,7 +8,9 @@
         "innerHTML": "\n<div class=\"wp-block-button aligncenter\"><a class=\"wp-block-button__link\" href=\"https://github.com/WordPress/gutenberg\">Help build Gutenberg</a></div>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__categories.parsed.json b/test/integration/full-content/fixtures/core__categories.parsed.json
index fd26319c672aa..df39a8078db37 100644
--- a/test/integration/full-content/fixtures/core__categories.parsed.json
+++ b/test/integration/full-content/fixtures/core__categories.parsed.json
@@ -10,7 +10,9 @@
         "innerHTML": ""
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__code.parsed.json b/test/integration/full-content/fixtures/core__code.parsed.json
index 33e16d542820e..5aea1d9a14a01 100644
--- a/test/integration/full-content/fixtures/core__code.parsed.json
+++ b/test/integration/full-content/fixtures/core__code.parsed.json
@@ -1,12 +1,14 @@
 [
     {
         "blockName": "core/code",
-        "attrs": null,
+        "attrs": {},
         "innerBlocks": [],
         "innerHTML": "\n<pre class=\"wp-block-code\"><code>export default function MyButton() {\n\treturn &lt;Button&gt;Click Me!&lt;/Button&gt;;\n}</code></pre>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__column.parsed.json b/test/integration/full-content/fixtures/core__column.parsed.json
index aa8fa31564726..74b53bdf6ae96 100644
--- a/test/integration/full-content/fixtures/core__column.parsed.json
+++ b/test/integration/full-content/fixtures/core__column.parsed.json
@@ -1,17 +1,17 @@
 [
     {
         "blockName": "core/column",
-        "attrs": null,
+        "attrs": {},
         "innerBlocks": [
             {
                 "blockName": "core/paragraph",
-                "attrs": null,
+                "attrs": {},
                 "innerBlocks": [],
                 "innerHTML": "\n\t<p>Column One, Paragraph One</p>\n\t"
             },
             {
                 "blockName": "core/paragraph",
-                "attrs": null,
+                "attrs": {},
                 "innerBlocks": [],
                 "innerHTML": "\n\t<p>Column One, Paragraph Two</p>\n\t"
             }
@@ -19,7 +19,9 @@
         "innerHTML": "\n<div class=\"wp-block-column\">\n\t\n\t\n</div>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__columns.parsed.json b/test/integration/full-content/fixtures/core__columns.parsed.json
index 5be49bbdceb12..9ec5cef66ad23 100644
--- a/test/integration/full-content/fixtures/core__columns.parsed.json
+++ b/test/integration/full-content/fixtures/core__columns.parsed.json
@@ -7,17 +7,17 @@
         "innerBlocks": [
             {
                 "blockName": "core/column",
-                "attrs": null,
+                "attrs": {},
                 "innerBlocks": [
                     {
                         "blockName": "core/paragraph",
-                        "attrs": null,
+                        "attrs": {},
                         "innerBlocks": [],
                         "innerHTML": "\n\t\t<p>Column One, Paragraph One</p>\n\t\t"
                     },
                     {
                         "blockName": "core/paragraph",
-                        "attrs": null,
+                        "attrs": {},
                         "innerBlocks": [],
                         "innerHTML": "\n\t\t<p>Column One, Paragraph Two</p>\n\t\t"
                     }
@@ -26,17 +26,17 @@
             },
             {
                 "blockName": "core/column",
-                "attrs": null,
+                "attrs": {},
                 "innerBlocks": [
                     {
                         "blockName": "core/paragraph",
-                        "attrs": null,
+                        "attrs": {},
                         "innerBlocks": [],
                         "innerHTML": "\n\t\t<p>Column Two, Paragraph One</p>\n\t\t"
                     },
                     {
                         "blockName": "core/paragraph",
-                        "attrs": null,
+                        "attrs": {},
                         "innerBlocks": [],
                         "innerHTML": "\n\t\t<p>Column Three, Paragraph One</p>\n\t\t"
                     }
@@ -47,7 +47,9 @@
         "innerHTML": "\n<div class=\"wp-block-columns has-3-columns\">\n\t\n\t\n</div>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__cover-image.parsed.json b/test/integration/full-content/fixtures/core__cover-image.parsed.json
index 25808e4279256..93bc4fbc8ddfd 100644
--- a/test/integration/full-content/fixtures/core__cover-image.parsed.json
+++ b/test/integration/full-content/fixtures/core__cover-image.parsed.json
@@ -9,7 +9,9 @@
         "innerHTML": "\n<div class=\"wp-block-cover-image has-background-dim-40 has-background-dim\" style=\"background-image:url(https://cldup.com/uuUqE_dXzy.jpg)\">\n    <p class=\"wp-block-cover-image-text\">Guten Berg!</p>\n</div>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__embed.parsed.json b/test/integration/full-content/fixtures/core__embed.parsed.json
index 70c14e2a61868..5efa23bb5f83c 100644
--- a/test/integration/full-content/fixtures/core__embed.parsed.json
+++ b/test/integration/full-content/fixtures/core__embed.parsed.json
@@ -8,7 +8,9 @@
         "innerHTML": "\n<figure class=\"wp-block-embed\">\n    <div class=\"wp-block-embed__wrapper\">\n        https://example.com/\n    </div>\n    <figcaption>Embedded content from an example URL</figcaption>\n</figure>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__file__new-window.parsed.json b/test/integration/full-content/fixtures/core__file__new-window.parsed.json
index 5781323e0750b..481c7e5c98daf 100644
--- a/test/integration/full-content/fixtures/core__file__new-window.parsed.json
+++ b/test/integration/full-content/fixtures/core__file__new-window.parsed.json
@@ -10,7 +10,9 @@
         "innerHTML": "\n<div class=\"wp-block-file\"><a href=\"http://localhost:8888/wp-content/uploads/2018/05/keycodes.js\" target=\"_blank\" rel=\"noreferrer noopener\">6546</a><a href=\"http://localhost:8888/wp-content/uploads/2018/05/keycodes.js\" class=\"wp-block-file__button\" download=\"6546\">Download</a></div>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__file__no-download-button.parsed.json b/test/integration/full-content/fixtures/core__file__no-download-button.parsed.json
index 68febde803b4c..65a2cffa5ec9a 100644
--- a/test/integration/full-content/fixtures/core__file__no-download-button.parsed.json
+++ b/test/integration/full-content/fixtures/core__file__no-download-button.parsed.json
@@ -10,7 +10,9 @@
         "innerHTML": "\n<div class=\"wp-block-file\"><a href=\"http://localhost:8888/?attachment_id=176\">lkjfijwef</a></div>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__file__no-text-link.parsed.json b/test/integration/full-content/fixtures/core__file__no-text-link.parsed.json
index 2789748adf97a..c905766eb9ca2 100644
--- a/test/integration/full-content/fixtures/core__file__no-text-link.parsed.json
+++ b/test/integration/full-content/fixtures/core__file__no-text-link.parsed.json
@@ -10,7 +10,9 @@
         "innerHTML": "\n<div class=\"wp-block-file\"><a href=\"http://localhost:8888/wp-content/uploads/2018/05/keycodes.js\" class=\"wp-block-file__button\" download=\"\">Download</a></div>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__freeform.parsed.json b/test/integration/full-content/fixtures/core__freeform.parsed.json
index dcb77b572d824..5cf330c0e9e99 100644
--- a/test/integration/full-content/fixtures/core__freeform.parsed.json
+++ b/test/integration/full-content/fixtures/core__freeform.parsed.json
@@ -1,12 +1,14 @@
 [
     {
         "blockName": "core/freeform",
-        "attrs": null,
+        "attrs": {},
         "innerBlocks": [],
         "innerHTML": "\nTesting freeform block with some\n<div class=\"wp-some-class\">\n\tHTML <span style=\"color: red;\">content</span>\n</div>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__freeform__undelimited.parsed.json b/test/integration/full-content/fixtures/core__freeform__undelimited.parsed.json
index 2301e078c045f..e0b2c76f29562 100644
--- a/test/integration/full-content/fixtures/core__freeform__undelimited.parsed.json
+++ b/test/integration/full-content/fixtures/core__freeform__undelimited.parsed.json
@@ -1,6 +1,8 @@
 [
     {
         "attrs": {},
+        "blockName": null,
+        "innerBlocks": [],
         "innerHTML": "Testing freeform block with some\n<div class=\"wp-some-class\">\n\tHTML <span style=\"color: red;\">content</span>\n</div>\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__gallery.parsed.json b/test/integration/full-content/fixtures/core__gallery.parsed.json
index aebcb2c1f36fd..3d80657c7f204 100644
--- a/test/integration/full-content/fixtures/core__gallery.parsed.json
+++ b/test/integration/full-content/fixtures/core__gallery.parsed.json
@@ -1,12 +1,14 @@
 [
     {
         "blockName": "core/gallery",
-        "attrs": null,
+        "attrs": {},
         "innerBlocks": [],
         "innerHTML": "\n<ul class=\"wp-block-gallery columns-2 is-cropped\">\n\t<li class=\"blocks-gallery-item\">\n\t\t<figure>\n\t\t\t<img src=\"https://cldup.com/uuUqE_dXzy.jpg\" alt=\"title\" />\n\t\t</figure>\n\t</li>\n\t<li class=\"blocks-gallery-item\">\n\t\t<figure>\n\t\t\t<img src=\"http://google.com/hi.png\" alt=\"title\" />\n\t\t</figure>\n\t</li>\n</ul>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__gallery__columns.parsed.json b/test/integration/full-content/fixtures/core__gallery__columns.parsed.json
index be994ed4a386a..44faed907a8fc 100644
--- a/test/integration/full-content/fixtures/core__gallery__columns.parsed.json
+++ b/test/integration/full-content/fixtures/core__gallery__columns.parsed.json
@@ -8,7 +8,9 @@
         "innerHTML": "\n<ul class=\"wp-block-gallery columns-1 is-cropped\">\n\t<li class=\"blocks-gallery-item\">\n\t\t<figure>\n\t\t\t<img src=\"https://cldup.com/uuUqE_dXzy.jpg\" alt=\"title\" />\n\t\t</figure>\n\t</li>\n\t<li class=\"blocks-gallery-item\">\n\t\t<figure>\n\t\t\t<img src=\"http://google.com/hi.png\" alt=\"title\" />\n\t\t</figure>\n\t</li>\n</ul>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__heading__h2-em.parsed.json b/test/integration/full-content/fixtures/core__heading__h2-em.parsed.json
index 1875c71488482..76d235d42c896 100644
--- a/test/integration/full-content/fixtures/core__heading__h2-em.parsed.json
+++ b/test/integration/full-content/fixtures/core__heading__h2-em.parsed.json
@@ -1,12 +1,14 @@
 [
     {
         "blockName": "core/heading",
-        "attrs": null,
+        "attrs": {},
         "innerBlocks": [],
         "innerHTML": "\n<h2>The <em>Inserter</em> Tool</h2>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__heading__h2.parsed.json b/test/integration/full-content/fixtures/core__heading__h2.parsed.json
index 3da53cb01d05d..700f5f941e3fd 100644
--- a/test/integration/full-content/fixtures/core__heading__h2.parsed.json
+++ b/test/integration/full-content/fixtures/core__heading__h2.parsed.json
@@ -1,12 +1,14 @@
 [
     {
         "blockName": "core/heading",
-        "attrs": null,
+        "attrs": {},
         "innerBlocks": [],
         "innerHTML": "\n<h2>A picture is worth a thousand words, or so the saying goes</h2>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__html.parsed.json b/test/integration/full-content/fixtures/core__html.parsed.json
index 353e0ad63792b..2bfdc658667ae 100644
--- a/test/integration/full-content/fixtures/core__html.parsed.json
+++ b/test/integration/full-content/fixtures/core__html.parsed.json
@@ -1,12 +1,14 @@
 [
     {
         "blockName": "core/html",
-        "attrs": null,
+        "attrs": {},
         "innerBlocks": [],
         "innerHTML": "\n<h1>Some HTML code</h1>\n<marquee>This text will scroll from right to left</marquee>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__image.parsed.json b/test/integration/full-content/fixtures/core__image.parsed.json
index eba958b3ec9a3..fff414d9b01ba 100644
--- a/test/integration/full-content/fixtures/core__image.parsed.json
+++ b/test/integration/full-content/fixtures/core__image.parsed.json
@@ -1,12 +1,14 @@
 [
     {
         "blockName": "core/image",
-        "attrs": null,
+        "attrs": {},
         "innerBlocks": [],
         "innerHTML": "\n<figure class=\"wp-block-image\"><img src=\"https://cldup.com/uuUqE_dXzy.jpg\" alt=\"\" /></figure>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__image__attachment-link.parsed.json b/test/integration/full-content/fixtures/core__image__attachment-link.parsed.json
index ddf8f9ba6a264..e5da07242d556 100644
--- a/test/integration/full-content/fixtures/core__image__attachment-link.parsed.json
+++ b/test/integration/full-content/fixtures/core__image__attachment-link.parsed.json
@@ -8,7 +8,9 @@
         "innerHTML": "\n<figure class=\"wp-block-image\"><a href=\"http://localhost:8888/?attachment_id=7\"><img src=\"https://cldup.com/uuUqE_dXzy.jpg\" alt=\"\" /></a></figure>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__image__center-caption.parsed.json b/test/integration/full-content/fixtures/core__image__center-caption.parsed.json
index e3a0f7abeb76a..290057c2876a7 100644
--- a/test/integration/full-content/fixtures/core__image__center-caption.parsed.json
+++ b/test/integration/full-content/fixtures/core__image__center-caption.parsed.json
@@ -8,7 +8,9 @@
         "innerHTML": "\n<div class=\"wp-block-image\"><figure class=\"aligncenter\"><img src=\"https://cldup.com/YLYhpou2oq.jpg\" alt=\"\" /><figcaption>Give it a try. Press the &quot;really wide&quot; button on the image toolbar.</figcaption></figure></div>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__image__custom-link.parsed.json b/test/integration/full-content/fixtures/core__image__custom-link.parsed.json
index fc004f13447ea..d814737aaedf2 100644
--- a/test/integration/full-content/fixtures/core__image__custom-link.parsed.json
+++ b/test/integration/full-content/fixtures/core__image__custom-link.parsed.json
@@ -8,7 +8,9 @@
         "innerHTML": "\n<figure class=\"wp-block-image\"><a href=\"https://wordpress.org/\"><img src=\"https://cldup.com/uuUqE_dXzy.jpg\" alt=\"\" /></a></figure>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__image__media-link.parsed.json b/test/integration/full-content/fixtures/core__image__media-link.parsed.json
index a7101b0afa410..345c5d4e258ed 100644
--- a/test/integration/full-content/fixtures/core__image__media-link.parsed.json
+++ b/test/integration/full-content/fixtures/core__image__media-link.parsed.json
@@ -8,7 +8,9 @@
         "innerHTML": "\n<figure class=\"wp-block-image\"><a href=\"https://cldup.com/uuUqE_dXzy.jpg\"><img src=\"https://cldup.com/uuUqE_dXzy.jpg\" alt=\"\" /></a></figure>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__invalid-Capitals.parsed.json b/test/integration/full-content/fixtures/core__invalid-Capitals.parsed.json
index 51888e4529cfb..c17c81b398cf3 100644
--- a/test/integration/full-content/fixtures/core__invalid-Capitals.parsed.json
+++ b/test/integration/full-content/fixtures/core__invalid-Capitals.parsed.json
@@ -1,6 +1,8 @@
 [
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "<!-- wp:core/invalid-Capitals /-->\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__invalid-special.parsed.json b/test/integration/full-content/fixtures/core__invalid-special.parsed.json
index 97c7af3387253..3198b43be513a 100644
--- a/test/integration/full-content/fixtures/core__invalid-special.parsed.json
+++ b/test/integration/full-content/fixtures/core__invalid-special.parsed.json
@@ -1,6 +1,8 @@
 [
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "<!-- wp:core/invalid-$special /-->\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__latest-comments.parsed.json b/test/integration/full-content/fixtures/core__latest-comments.parsed.json
index a8806d27be5a4..7e8bb541adc0c 100644
--- a/test/integration/full-content/fixtures/core__latest-comments.parsed.json
+++ b/test/integration/full-content/fixtures/core__latest-comments.parsed.json
@@ -10,7 +10,9 @@
         "innerHTML": ""
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__latest-posts.parsed.json b/test/integration/full-content/fixtures/core__latest-posts.parsed.json
index 8a1e08c3de8ea..f1c800291d9bc 100644
--- a/test/integration/full-content/fixtures/core__latest-posts.parsed.json
+++ b/test/integration/full-content/fixtures/core__latest-posts.parsed.json
@@ -9,7 +9,9 @@
         "innerHTML": ""
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__latest-posts__displayPostDate.parsed.json b/test/integration/full-content/fixtures/core__latest-posts__displayPostDate.parsed.json
index 05537ff5f9d1b..a92b392679099 100644
--- a/test/integration/full-content/fixtures/core__latest-posts__displayPostDate.parsed.json
+++ b/test/integration/full-content/fixtures/core__latest-posts__displayPostDate.parsed.json
@@ -9,7 +9,9 @@
         "innerHTML": ""
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__list__ul.parsed.json b/test/integration/full-content/fixtures/core__list__ul.parsed.json
index ede855355021f..c42181ba553ac 100644
--- a/test/integration/full-content/fixtures/core__list__ul.parsed.json
+++ b/test/integration/full-content/fixtures/core__list__ul.parsed.json
@@ -1,12 +1,14 @@
 [
     {
         "blockName": "core/list",
-        "attrs": null,
+        "attrs": {},
         "innerBlocks": [],
         "innerHTML": "\n<ul><li>Text & Headings</li><li>Images & Videos</li><li>Galleries</li><li>Embeds, like YouTube, Tweets, or other WordPress posts.</li><li>Layout blocks, like Buttons, Hero Images, Separators, etc.</li><li>And <em>Lists</em> like this one of course :)</li></ul>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__more.parsed.json b/test/integration/full-content/fixtures/core__more.parsed.json
index cdf33d5851657..176e7fe7f7c16 100644
--- a/test/integration/full-content/fixtures/core__more.parsed.json
+++ b/test/integration/full-content/fixtures/core__more.parsed.json
@@ -1,12 +1,14 @@
 [
     {
         "blockName": "core/more",
-        "attrs": null,
+        "attrs": {},
         "innerBlocks": [],
         "innerHTML": "\n<!--more-->\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__more__custom-text-teaser.parsed.json b/test/integration/full-content/fixtures/core__more__custom-text-teaser.parsed.json
index 6bf85564708c2..a533e3c09c471 100644
--- a/test/integration/full-content/fixtures/core__more__custom-text-teaser.parsed.json
+++ b/test/integration/full-content/fixtures/core__more__custom-text-teaser.parsed.json
@@ -9,7 +9,9 @@
         "innerHTML": "\n<!--more Continue Reading-->\n<!--noteaser-->\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__nextpage.parsed.json b/test/integration/full-content/fixtures/core__nextpage.parsed.json
index 0dde31a4bf41a..e4dd2534c821e 100644
--- a/test/integration/full-content/fixtures/core__nextpage.parsed.json
+++ b/test/integration/full-content/fixtures/core__nextpage.parsed.json
@@ -1,12 +1,14 @@
 [
     {
         "blockName": "core/nextpage",
-        "attrs": null,
+        "attrs": {},
         "innerBlocks": [],
         "innerHTML": "\n<!--nextpage-->\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__paragraph__align-right.parsed.json b/test/integration/full-content/fixtures/core__paragraph__align-right.parsed.json
index 754b7905b1331..060d40a38de5a 100644
--- a/test/integration/full-content/fixtures/core__paragraph__align-right.parsed.json
+++ b/test/integration/full-content/fixtures/core__paragraph__align-right.parsed.json
@@ -8,7 +8,9 @@
         "innerHTML": "\n<p style=\"text-align:right;\">... like this one, which is separate from the above and right aligned.</p>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__paragraph__deprecated.parsed.json b/test/integration/full-content/fixtures/core__paragraph__deprecated.parsed.json
index 11217876b3cb4..ac11af1b3a92c 100644
--- a/test/integration/full-content/fixtures/core__paragraph__deprecated.parsed.json
+++ b/test/integration/full-content/fixtures/core__paragraph__deprecated.parsed.json
@@ -1,12 +1,14 @@
 [
     {
         "blockName": "core/paragraph",
-        "attrs": null,
+        "attrs": {},
         "innerBlocks": [],
         "innerHTML": "\nUnwrapped is <em>still</em> valid.\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__preformatted.parsed.json b/test/integration/full-content/fixtures/core__preformatted.parsed.json
index ae7e771924c29..247fdda2e3eee 100644
--- a/test/integration/full-content/fixtures/core__preformatted.parsed.json
+++ b/test/integration/full-content/fixtures/core__preformatted.parsed.json
@@ -1,12 +1,14 @@
 [
     {
         "blockName": "core/preformatted",
-        "attrs": null,
+        "attrs": {},
         "innerBlocks": [],
         "innerHTML": "\n<pre class=\"wp-block-preformatted\">Some <em>preformatted</em> text...<br>And more!</pre>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__pullquote.parsed.json b/test/integration/full-content/fixtures/core__pullquote.parsed.json
index bafaa101c2d0a..0e39eea4ec89c 100644
--- a/test/integration/full-content/fixtures/core__pullquote.parsed.json
+++ b/test/integration/full-content/fixtures/core__pullquote.parsed.json
@@ -1,12 +1,14 @@
 [
     {
         "blockName": "core/pullquote",
-        "attrs": null,
+        "attrs": {},
         "innerBlocks": [],
         "innerHTML": "\n<figure class=\"wp-block-pullquote\">\n    <blockquote>\n    <p>Testing pullquote block...</p><cite>...with a caption</cite>\n    </blockquote>\n</figure>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__pullquote__multi-paragraph.parsed.json b/test/integration/full-content/fixtures/core__pullquote__multi-paragraph.parsed.json
index ee9cee5764b70..3b303a0d8d157 100644
--- a/test/integration/full-content/fixtures/core__pullquote__multi-paragraph.parsed.json
+++ b/test/integration/full-content/fixtures/core__pullquote__multi-paragraph.parsed.json
@@ -1,12 +1,14 @@
 [
     {
         "blockName": "core/pullquote",
-        "attrs": null,
+        "attrs": {},
         "innerBlocks": [],
         "innerHTML": "\n<figure class=\"wp-block-pullquote\">\n    <blockquote>\n        <p>Paragraph <strong>one</strong></p>\n        <p>Paragraph two</p>\n        <cite>by whomever</cite>\n\t</blockquote>\n</figure>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__quote__style-1.parsed.json b/test/integration/full-content/fixtures/core__quote__style-1.parsed.json
index 09553fed152db..12f480ef313fe 100644
--- a/test/integration/full-content/fixtures/core__quote__style-1.parsed.json
+++ b/test/integration/full-content/fixtures/core__quote__style-1.parsed.json
@@ -1,12 +1,14 @@
 [
     {
         "blockName": "core/quote",
-        "attrs": null,
+        "attrs": {},
         "innerBlocks": [],
         "innerHTML": "\n<blockquote class=\"wp-block-quote\"><p>The editor will endeavour to create a new page and post building experience that makes writing rich posts effortless, and has “blocks” to make it easy what today might take shortcodes, custom HTML, or “mystery meat” embed discovery.</p><cite>Matt Mullenweg, 2017</cite></blockquote>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__quote__style-2.parsed.json b/test/integration/full-content/fixtures/core__quote__style-2.parsed.json
index d1098fffcdf0a..87a9377e2e9ed 100644
--- a/test/integration/full-content/fixtures/core__quote__style-2.parsed.json
+++ b/test/integration/full-content/fixtures/core__quote__style-2.parsed.json
@@ -8,7 +8,9 @@
         "innerHTML": "\n<blockquote class=\"wp-block-quote is-style-large\"><p>There is no greater agony than bearing an untold story inside you.</p><cite>Maya Angelou</cite></blockquote>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__separator.parsed.json b/test/integration/full-content/fixtures/core__separator.parsed.json
index fc45ffa4171c9..d01eb1eed1f59 100644
--- a/test/integration/full-content/fixtures/core__separator.parsed.json
+++ b/test/integration/full-content/fixtures/core__separator.parsed.json
@@ -1,12 +1,14 @@
 [
     {
         "blockName": "core/separator",
-        "attrs": null,
+        "attrs": {},
         "innerBlocks": [],
         "innerHTML": "\n<hr class=\"wp-block-separator\" />\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__shortcode.parsed.json b/test/integration/full-content/fixtures/core__shortcode.parsed.json
index 0716f8f3ee3d3..70d24dc276253 100644
--- a/test/integration/full-content/fixtures/core__shortcode.parsed.json
+++ b/test/integration/full-content/fixtures/core__shortcode.parsed.json
@@ -1,12 +1,14 @@
 [
     {
         "blockName": "core/shortcode",
-        "attrs": null,
+        "attrs": {},
         "innerBlocks": [],
         "innerHTML": "\n[gallery ids=\"238,338\"]\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__spacer.parsed.json b/test/integration/full-content/fixtures/core__spacer.parsed.json
index e5dad726275f4..8b8baa2a7fc61 100644
--- a/test/integration/full-content/fixtures/core__spacer.parsed.json
+++ b/test/integration/full-content/fixtures/core__spacer.parsed.json
@@ -1,12 +1,14 @@
 [
     {
         "blockName": "core/spacer",
-        "attrs": null,
+        "attrs": {},
         "innerBlocks": [],
         "innerHTML": "\n<div style=\"height:100px\" aria-hidden=\"true\" class=\"wp-block-spacer\"></div>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__subhead.parsed.json b/test/integration/full-content/fixtures/core__subhead.parsed.json
index effd9c882a99f..06ca46da1b88d 100644
--- a/test/integration/full-content/fixtures/core__subhead.parsed.json
+++ b/test/integration/full-content/fixtures/core__subhead.parsed.json
@@ -1,12 +1,14 @@
 [
     {
         "blockName": "core/subhead",
-        "attrs": null,
+        "attrs": {},
         "innerBlocks": [],
         "innerHTML": "\n<p class=\"wp-block-subhead\">This is a <em>subhead</em>.</p>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__table.parsed.json b/test/integration/full-content/fixtures/core__table.parsed.json
index 737ac5ea49098..8c24b96113b94 100644
--- a/test/integration/full-content/fixtures/core__table.parsed.json
+++ b/test/integration/full-content/fixtures/core__table.parsed.json
@@ -1,12 +1,14 @@
 [
     {
         "blockName": "core/table",
-        "attrs": null,
+        "attrs": {},
         "innerBlocks": [],
         "innerHTML": "\n<table class=\"wp-block-table\"><thead><tr><th>Version</th><th>Musician</th><th>Date</th></tr></thead><tbody><tr><td><a href=\"https://wordpress.org/news/2003/05/wordpress-now-available/\">.70</a></td><td>No musician chosen.</td><td>May 27, 2003</td></tr><tr><td><a href=\"https://wordpress.org/news/2004/01/wordpress-10/\">1.0</a></td><td>Miles Davis</td><td>January 3, 2004</td></tr><tr><td>Lots of versions skipped, see <a href=\"https://codex.wordpress.org/WordPress_Versions\">the full list</a></td><td>&hellip;</td><td>&hellip;</td></tr><tr><td><a href=\"https://wordpress.org/news/2015/12/clifford/\">4.4</a></td><td>Clifford Brown</td><td>December 8, 2015</td></tr><tr><td><a href=\"https://wordpress.org/news/2016/04/coleman/\">4.5</a></td><td>Coleman Hawkins</td><td>April 12, 2016</td></tr><tr><td><a href=\"https://wordpress.org/news/2016/08/pepper/\">4.6</a></td><td>Pepper Adams</td><td>August 16, 2016</td></tr><tr><td><a href=\"https://wordpress.org/news/2016/12/vaughan/\">4.7</a></td><td>Sarah Vaughan</td><td>December 6, 2016</td></tr></tbody></table>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__text-columns.parsed.json b/test/integration/full-content/fixtures/core__text-columns.parsed.json
index a03bb73ef0112..293c930ac59e6 100644
--- a/test/integration/full-content/fixtures/core__text-columns.parsed.json
+++ b/test/integration/full-content/fixtures/core__text-columns.parsed.json
@@ -8,7 +8,9 @@
         "innerHTML": "\n<div class=\"wp-block-text-columns aligncenter columns-2\">\n    <div class=\"wp-block-column\">\n        <p>One</p>\n    </div>\n    <div class=\"wp-block-column\">\n        <p>Two</p>\n    </div>\n</div>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__text__converts-to-paragraph.parsed.json b/test/integration/full-content/fixtures/core__text__converts-to-paragraph.parsed.json
index cf43c349c48ad..958d2a2921327 100644
--- a/test/integration/full-content/fixtures/core__text__converts-to-paragraph.parsed.json
+++ b/test/integration/full-content/fixtures/core__text__converts-to-paragraph.parsed.json
@@ -1,12 +1,14 @@
 [
     {
         "blockName": "core/text",
-        "attrs": null,
+        "attrs": {},
         "innerBlocks": [],
         "innerHTML": "\n<p>This is an old-style text block.  Changed to <code>paragraph</code> in #2135.</p>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__verse.parsed.json b/test/integration/full-content/fixtures/core__verse.parsed.json
index f2c3df3867f3c..4f244cb551d50 100644
--- a/test/integration/full-content/fixtures/core__verse.parsed.json
+++ b/test/integration/full-content/fixtures/core__verse.parsed.json
@@ -1,12 +1,14 @@
 [
     {
         "blockName": "core/verse",
-        "attrs": null,
+        "attrs": {},
         "innerBlocks": [],
         "innerHTML": "\n<pre class=\"wp-block-verse\">A <em>verse</em>…<br>And more!</pre>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]
diff --git a/test/integration/full-content/fixtures/core__video.parsed.json b/test/integration/full-content/fixtures/core__video.parsed.json
index 5d445ce5c0ab3..7b448d6f380d9 100644
--- a/test/integration/full-content/fixtures/core__video.parsed.json
+++ b/test/integration/full-content/fixtures/core__video.parsed.json
@@ -1,12 +1,14 @@
 [
     {
         "blockName": "core/video",
-        "attrs": null,
+        "attrs": {},
         "innerBlocks": [],
         "innerHTML": "\n<figure class=\"wp-block-video\"><video controls src=\"https://awesome-fake.video/file.mp4\"></video></figure>\n"
     },
     {
+        "blockName": null,
         "attrs": {},
+        "innerBlocks": [],
         "innerHTML": "\n"
     }
 ]