diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 8f40d9880d..436d585254 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -48,6 +48,32 @@ jobs:
       - name: Build package
         run: npm run build
 
+  fuzz:
+    name: Run fuzzing tests on Node v${{ matrix.node_version }}
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repo
+        uses: actions/checkout@v2
+
+      - name: Setup Node.js v${{ matrix.node_version }}
+        uses: actions/setup-node@v1
+        with:
+          node-version: ${{ matrix.node_version }}
+
+      - name: Cache Node.js modules
+        uses: actions/cache@v1
+        with:
+          path: ~/.npm
+          key: ${{ runner.OS }}-node-${{ hashFiles('**/package-lock.json') }}
+          restore-keys: |
+            ${{ runner.OS }}-node-
+
+      - name: Install Dependencies
+        run: npm ci
+
+      - name: Run Tests
+        run: npm run fuzzonly
+
   coverage:
     name: Measure test coverage
     runs-on: ubuntu-latest
@@ -114,7 +140,7 @@ jobs:
       github.event_name == 'push' &&
       github.repository == 'graphql/graphql-js' &&
       github.ref == 'refs/heads/master'
-    needs: [test, lint]
+    needs: [test, fuzz, lint]
     steps:
       - name: Checkout repo
         uses: actions/checkout@v2
diff --git a/.nycrc.yml b/.nycrc.yml
index b057456271..ad74db4ae2 100644
--- a/.nycrc.yml
+++ b/.nycrc.yml
@@ -3,6 +3,7 @@ include:
   - 'src/'
 exclude:
   - 'src/polyfills'
+  - '**/*-fuzz.js'
   - '**/*-benchmark.js'
   - '**/*.d.ts'
   - 'src/validation/rules/ExecutableDefinitions.js'
diff --git a/package.json b/package.json
index bdf39204e3..7c4da5ead3 100644
--- a/package.json
+++ b/package.json
@@ -27,6 +27,7 @@
   "scripts": {
     "test": "npm run prettier:check && npm run lint && npm run check && npm run testonly && npm run check:ts && npm run check:spelling",
     "test:ci": "npm run prettier:check && npm run lint -- --no-cache && npm run check && npm run testonly:cover && npm run check:ts && npm run check:spelling && npm run build",
+    "fuzzonly": "mocha --full-trace src/**/__tests__/**/*-fuzz.js",
     "testonly": "mocha --full-trace src/**/__tests__/**/*-test.js",
     "testonly:cover": "nyc npm run testonly",
     "lint": "eslint --cache --ext .js,.ts src resources",
diff --git a/src/language/__tests__/blockString-fuzz.js b/src/language/__tests__/blockString-fuzz.js
new file mode 100644
index 0000000000..7f11302e6d
--- /dev/null
+++ b/src/language/__tests__/blockString-fuzz.js
@@ -0,0 +1,68 @@
+// @flow strict
+
+import { describe, it } from 'mocha';
+
+import dedent from '../../__testUtils__/dedent';
+import inspectStr from '../../__testUtils__/inspectStr';
+import genFuzzStrings from '../../__testUtils__/genFuzzStrings';
+
+import invariant from '../../jsutils/invariant';
+
+import { Lexer } from '../lexer';
+import { Source } from '../source';
+import { printBlockString } from '../blockString';
+
+function lexValue(str) {
+  const lexer = new Lexer(new Source(str));
+  const value = lexer.advance().value;
+
+  invariant(lexer.advance().kind === '<EOF>', 'Expected EOF');
+  return value;
+}
+
+describe('printBlockString', () => {
+  it('correctly print random strings', () => {
+    // Testing with length >7 is taking exponentially more time. However it is
+    // highly recommended to test with increased limit if you make any change.
+    for (const fuzzStr of genFuzzStrings({
+      allowedChars: ['\n', '\t', ' ', '"', 'a', '\\'],
+      maxLength: 7,
+    })) {
+      const testStr = '"""' + fuzzStr + '"""';
+
+      let testValue;
+      try {
+        testValue = lexValue(testStr);
+      } catch (e) {
+        continue; // skip invalid values
+      }
+      invariant(typeof testValue === 'string');
+
+      const printedValue = lexValue(printBlockString(testValue));
+
+      invariant(
+        testValue === printedValue,
+        dedent`
+          Expected lexValue(printBlockString(${inspectStr(testValue)}))
+            to equal ${inspectStr(testValue)}
+            but got  ${inspectStr(printedValue)}
+        `,
+      );
+
+      const printedMultilineString = lexValue(
+        printBlockString(testValue, ' ', true),
+      );
+
+      invariant(
+        testValue === printedMultilineString,
+        dedent`
+          Expected lexValue(printBlockString(${inspectStr(
+            testValue,
+          )}, ' ', true))
+            to equal ${inspectStr(testValue)}
+            but got  ${inspectStr(printedMultilineString)}
+        `,
+      );
+    }
+  }).timeout(20000);
+});
diff --git a/src/language/__tests__/blockString-test.js b/src/language/__tests__/blockString-test.js
index f4968cdafc..efd7abbd45 100644
--- a/src/language/__tests__/blockString-test.js
+++ b/src/language/__tests__/blockString-test.js
@@ -3,14 +3,6 @@
 import { expect } from 'chai';
 import { describe, it } from 'mocha';
 
-import dedent from '../../__testUtils__/dedent';
-import inspectStr from '../../__testUtils__/inspectStr';
-import genFuzzStrings from '../../__testUtils__/genFuzzStrings';
-
-import invariant from '../../jsutils/invariant';
-
-import { Lexer } from '../lexer';
-import { Source } from '../source';
 import {
   dedentBlockStringValue,
   getBlockStringIndentation,
@@ -189,57 +181,4 @@ describe('printBlockString', () => {
       ),
     );
   });
-
-  it('correctly print random strings', () => {
-    // Testing with length >5 is taking exponentially more time. However it is
-    // highly recommended to test with increased limit if you make any change.
-    for (const fuzzStr of genFuzzStrings({
-      allowedChars: ['\n', '\t', ' ', '"', 'a', '\\'],
-      maxLength: 5,
-    })) {
-      const testStr = '"""' + fuzzStr + '"""';
-
-      let testValue;
-      try {
-        testValue = lexValue(testStr);
-      } catch (e) {
-        continue; // skip invalid values
-      }
-      invariant(typeof testValue === 'string');
-
-      const printedValue = lexValue(printBlockString(testValue));
-
-      invariant(
-        testValue === printedValue,
-        dedent`
-          Expected lexValue(printBlockString(${inspectStr(testValue)}))
-            to equal ${inspectStr(testValue)}
-            but got  ${inspectStr(printedValue)}
-        `,
-      );
-
-      const printedMultilineString = lexValue(
-        printBlockString(testValue, ' ', true),
-      );
-
-      invariant(
-        testValue === printedMultilineString,
-        dedent`
-          Expected lexValue(printBlockString(${inspectStr(
-            testValue,
-          )}, ' ', true))
-            to equal ${inspectStr(testValue)}
-            but got  ${inspectStr(printedMultilineString)}
-        `,
-      );
-    }
-
-    function lexValue(str) {
-      const lexer = new Lexer(new Source(str));
-      const value = lexer.advance().value;
-
-      invariant(lexer.advance().kind === '<EOF>', 'Expected EOF');
-      return value;
-    }
-  });
 });
diff --git a/src/utilities/__tests__/stripIgnoredCharacters-fuzz.js b/src/utilities/__tests__/stripIgnoredCharacters-fuzz.js
new file mode 100644
index 0000000000..c853e1e768
--- /dev/null
+++ b/src/utilities/__tests__/stripIgnoredCharacters-fuzz.js
@@ -0,0 +1,53 @@
+// @flow strict
+
+import { describe, it } from 'mocha';
+
+import dedent from '../../__testUtils__/dedent';
+import inspectStr from '../../__testUtils__/inspectStr';
+import genFuzzStrings from '../../__testUtils__/genFuzzStrings';
+
+import invariant from '../../jsutils/invariant';
+
+import { Lexer } from '../../language/lexer';
+import { Source } from '../../language/source';
+
+import { stripIgnoredCharacters } from '../stripIgnoredCharacters';
+
+function lexValue(str) {
+  const lexer = new Lexer(new Source(str));
+  const value = lexer.advance().value;
+
+  invariant(lexer.advance().kind === '<EOF>', 'Expected EOF');
+  return value;
+}
+
+describe('stripIgnoredCharacters', () => {
+  it('strips ignored characters inside random block strings', () => {
+    // Testing with length >7 is taking exponentially more time. However it is
+    // highly recommended to test with increased limit if you make any change.
+    for (const fuzzStr of genFuzzStrings({
+      allowedChars: ['\n', '\t', ' ', '"', 'a', '\\'],
+      maxLength: 7,
+    })) {
+      const testStr = '"""' + fuzzStr + '"""';
+
+      let testValue;
+      try {
+        testValue = lexValue(testStr);
+      } catch (e) {
+        continue; // skip invalid values
+      }
+
+      const strippedValue = lexValue(stripIgnoredCharacters(testStr));
+
+      invariant(
+        testValue === strippedValue,
+        dedent`
+          Expected lexValue(stripIgnoredCharacters(${inspectStr(testStr)}))
+            to equal ${inspectStr(testValue)}
+            but got  ${inspectStr(strippedValue)}
+        `,
+      );
+    }
+  }).timeout(20000);
+});
diff --git a/src/utilities/__tests__/stripIgnoredCharacters-test.js b/src/utilities/__tests__/stripIgnoredCharacters-test.js
index cd4e675dc9..8ac48694f0 100644
--- a/src/utilities/__tests__/stripIgnoredCharacters-test.js
+++ b/src/utilities/__tests__/stripIgnoredCharacters-test.js
@@ -5,7 +5,6 @@ import { describe, it } from 'mocha';
 
 import dedent from '../../__testUtils__/dedent';
 import inspectStr from '../../__testUtils__/inspectStr';
-import genFuzzStrings from '../../__testUtils__/genFuzzStrings';
 
 import invariant from '../../jsutils/invariant';
 
@@ -438,35 +437,6 @@ describe('stripIgnoredCharacters', () => {
     expectStrippedString('"""\na\n b\nc"""').toEqual('"""a\n b\nc"""');
   });
 
-  it('strips ignored characters inside random block strings', () => {
-    // Testing with length >5 is taking exponentially more time. However it is
-    // highly recommended to test with increased limit if you make any change.
-    for (const fuzzStr of genFuzzStrings({
-      allowedChars: ['\n', '\t', ' ', '"', 'a', '\\'],
-      maxLength: 5,
-    })) {
-      const testStr = '"""' + fuzzStr + '"""';
-
-      let testValue;
-      try {
-        testValue = lexValue(testStr);
-      } catch (e) {
-        continue; // skip invalid values
-      }
-
-      const strippedValue = lexValue(stripIgnoredCharacters(testStr));
-
-      invariant(
-        testValue === strippedValue,
-        dedent`
-          Expected lexValue(stripIgnoredCharacters(${inspectStr(testStr)}))
-            to equal ${inspectStr(testValue)}
-            but got  ${inspectStr(strippedValue)}
-        `,
-      );
-    }
-  });
-
   it('strips kitchen sink query but maintains the exact same AST', () => {
     const strippedQuery = stripIgnoredCharacters(kitchenSinkQuery);
     expect(stripIgnoredCharacters(strippedQuery)).to.equal(strippedQuery);