diff --git a/tests/json/json-superset/jsfmt.spec.js b/tests/json/json-superset/jsfmt.spec.js
new file mode 100644
index 000000000..4bc498ad7
--- /dev/null
+++ b/tests/json/json-superset/jsfmt.spec.js
@@ -0,0 +1,78 @@
+const LINE_SEPARATOR = "\u2028";
+const PARAGRAPH_SEPARATOR = "\u2029";
+const SPACE = " ";
+const LINE_FEED = "\n";
+const UNDERSCORE = "_";
+const BACKSLASH = "\\";
+const SINGLE_QUOTE = "'";
+const DOUBLE_QUOTE = '"';
+
+const characters = [LINE_SEPARATOR, PARAGRAPH_SEPARATOR, UNDERSCORE, SPACE];
+const characterCode = (character) =>
+  `U+${character.charCodeAt(0).toString(16).toUpperCase().padStart(4, "0")}`;
+
+run_spec(
+  {
+    dirname: __dirname,
+    snippets: [
+      ...characters.map((character) => ({
+        name: `json(${characterCode(character)})`,
+        code: SINGLE_QUOTE + character + SINGLE_QUOTE,
+        output: DOUBLE_QUOTE + character + DOUBLE_QUOTE + LINE_FEED,
+      })),
+      ...[...characters, LINE_FEED].map((character) => ({
+        name: `json(\\${characterCode(character)})`,
+        code: SINGLE_QUOTE + BACKSLASH + character + SINGLE_QUOTE,
+        output:
+          character === UNDERSCORE || character === SPACE
+            ? DOUBLE_QUOTE + character + DOUBLE_QUOTE + LINE_FEED
+            : DOUBLE_QUOTE + BACKSLASH + character + DOUBLE_QUOTE + LINE_FEED,
+      })),
+      ...characters.map((character) => ({
+        name: `json(\\\\${characterCode(character)})`,
+        code: SINGLE_QUOTE + BACKSLASH + BACKSLASH + character + SINGLE_QUOTE,
+        output:
+          DOUBLE_QUOTE +
+          BACKSLASH +
+          BACKSLASH +
+          character +
+          DOUBLE_QUOTE +
+          LINE_FEED,
+      })),
+    ],
+  },
+  ["json", "json5"]
+);
+
+run_spec(
+  {
+    dirname: __dirname,
+    snippets: [
+      ...characters.map((character) => ({
+        name: `json-stringify(${characterCode(character)})`,
+        code: SINGLE_QUOTE + character + SINGLE_QUOTE,
+        output: DOUBLE_QUOTE + character + DOUBLE_QUOTE + LINE_FEED,
+      })),
+      ...[...characters, LINE_FEED].map((character) => ({
+        name: `json-stringify(\\${characterCode(character)})`,
+        code: SINGLE_QUOTE + BACKSLASH + character + SINGLE_QUOTE,
+        output:
+          character === UNDERSCORE || character === SPACE
+            ? DOUBLE_QUOTE + character + DOUBLE_QUOTE + LINE_FEED
+            : DOUBLE_QUOTE + DOUBLE_QUOTE + LINE_FEED,
+      })),
+      ...characters.map((character) => ({
+        name: `json-stringify(\\\\${characterCode(character)})`,
+        code: SINGLE_QUOTE + BACKSLASH + BACKSLASH + character + SINGLE_QUOTE,
+        output:
+          DOUBLE_QUOTE +
+          BACKSLASH +
+          BACKSLASH +
+          character +
+          DOUBLE_QUOTE +
+          LINE_FEED,
+      })),
+    ],
+  },
+  ["json-stringify"]
+);
diff --git a/tests_config/utils/check-parsers.js b/tests_config/utils/check-parsers.js
index dfd2b683c..38ba9966f 100644
--- a/tests_config/utils/check-parsers.js
+++ b/tests_config/utils/check-parsers.js
@@ -67,7 +67,7 @@ const categoryParsers = new Map([
     "json",
     {
       parsers: ["json", "json5", "json-stringify"],
-      verifyParsers: [],
+      verifyParsers: ["json", "json5", "json-stringify"],
       extensions: [".json"],
     },
   ],