CI with GitHub Action: run tokenizer fuzzing tests (#18841)

.github/workflows/fuzzing.yml

+name: Fuzzing
+
+on:
+  push:
+    branches:
+      - '**'
+    paths:
+    - 'frontend/**'
+    - 'shared/**'
+    - 'enterprise/frontend/**'
+    - 'docs/**'
+    - '**/package.json'
+    - '**/yarn.lock'
+    - '**/.eslintrc'
+    - '.github/workflows/**'
+  pull_request:
+
+jobs:
+
+  fe-fuzz-tokenizer:
+    runs-on: ubuntu-20.04
+    timeout-minutes: 7
+    steps:
+    - uses: actions/checkout@v2
+    - name: Prepare Node.js
+      uses: actions/setup-node@v1
+      with:
+        node-version: 14.x
+    - name: Get M2 cache
+      uses: actions/cache@v2
+      with:
+        path: ~/.m2
+        key: ${{ runner.os }}-cljs-${{ hashFiles('**/shadow-cljs.edn') }}
+    - name: Get yarn cache
+      uses: actions/cache@v2
+      with:
+        path: ~/.cache/yarn
+        key: ${{ runner.os }}-yarn-${{ hashFiles('**/yarn.lock') }}
+    - run: yarn install --frozen-lockfile --prefer-offline
+    - run: yarn test-unit frontend/test/metabase/lib/expressions/fuzz.tokenizer.unit.spec.js
+      env:
+        MB_FUZZ: 1
+      name: Run fuzz testing on the tokenizer

frontend/test/metabase/lib/expressions/fuzz.tokenizer.unit.spec.js

+import { tokenize } from "metabase/lib/expressions/tokenizer";
+
+import { generateExpression } from "./generator";
+
+const fuzz = process.env.MB_FUZZ ? describe : describe.skip;
+
+describe("metabase/lib/expressions/tokenizer", () => {
+  // quick sanity check before the real fuzzing
+  it("should tokenize custom expresssion", () => {
+    expect(() => tokenize("CASE([Deal],[Price]*7e-1,[Price]")).not.toThrow();
+  });
+});
+
+fuzz("FUZZING metabase/lib/expressions/tokenizer", () => {
+  const MAX_SEED = 5e4;
+
+  for (let seed = 0; seed < MAX_SEED; ++seed) {
+    it("should handle generated expression from seed " + seed, () => {
+      const { expression } = generateExpression(seed);
+      expect(() => tokenize(expression)).not.toThrow();
+    });
+    it("should not error on generated expression from seed " + seed, () => {
+      const { expression } = generateExpression(seed);
+      expect(tokenize(expression).errors).toEqual([]);
+    });
+  }
+});

frontend/test/metabase/lib/expressions/tokenizer.unit.spec.js

@@ -4,8 +4,6 @@ import {
   OPERATOR as OP,
 } from "metabase/lib/expressions/tokenizer";
 
-import { generateExpression } from "./generator";
-
 describe("metabase/lib/expressions/tokenizer", () => {
   const types = expr => tokenize(expr).tokens.map(t => t.type);
   const ops = expr => tokenize(expr).tokens.map(t => t.op);
@@ -142,20 +140,3 @@ describe("metabase/lib/expressions/tokenizer", () => {
     expect(errors("    #")[0].pos).toEqual(4);
   });
 });
-
-if (process.env.MB_FUZZ) {
-  describe("FUZZING metabase/lib/expressions/tokenizer", () => {
-    const MAX_SEED = 5e4;
-
-    for (let seed = 0; seed < MAX_SEED; ++seed) {
-      it("should handle generated expression from seed " + seed, () => {
-        const { expression } = generateExpression(seed);
-        expect(() => tokenize(expression)).not.toThrow();
-      });
-      it("should not error on generated expression from seed " + seed, () => {
-        const { expression } = generateExpression(seed);
-        expect(tokenize(expression).errors).toEqual([]);
-      });
-    }
-  });
-}