fix: support node:test snapshot corner-cases

Author: ChALkeR

.github/workflows/checks.yaml

@@ -34,7 +34,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        node-version: ['25', '24', '24.0.0', '22.22.0', '22.12.0', '20', '20.19.0']
+        node-version: ['25', '24', '24.0.0', '22.22.0', '22.12.0', '22.13.0', '20', '20.19.0']
     steps:
       - uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29
       - uses: pnpm/action-setup@a7487c7e89a18df4991f7f222e4898a00d66ddda
@@ -61,7 +61,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        node-version: ['25', '24', '24.0.0', '22.22.0', '22.12.0', '20', '20.19.0']
+        node-version: ['25', '24', '24.0.0', '22.22.0', '22.12.0', '22.13.0', '20', '20.19.0']
     steps:
       - uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29
       - uses: pnpm/action-setup@a7487c7e89a18df4991f7f222e4898a00d66ddda

src/engine.pure.cjs

@@ -564,7 +564,7 @@ if (process.env.EXODUS_TEST_ENVIRONMENT === 'bundle') {
 
 // eslint-disable-next-line no-undef
 let snapshotResolver = (dir, name) => [dir, `${name}.snapshot`] // default per Node.js docs
-let snapshotSerializers = [(obj) => JSON.stringify(obj, null, 2)]
+let snapshotSerializers = [(obj) => (obj === undefined ? `${obj}` : JSON.stringify(obj, null, 2))]
 const serializeSnapshot = (obj) => {
   let val = obj
   for (const fn of snapshotSerializers) val = fn(val)

src/engine.pure.snapshot.cjs

@@ -2,6 +2,7 @@ const nameCounts = new Map()
 let snapshotText, snapshotTextClean
 
 const escapeSnapshot = (str) => str.replaceAll(/([\\`]|\$\{)/gu, '\\$1')
+const escapeSnapshotKey = (s) => escapeSnapshot(s).replaceAll('\n', '\\n').replaceAll('"', '\\"')
 
 function matchSnapshot(readSnapshot, assert, name, serialized) {
   // We don't have native snapshots, polyfill reading
@@ -25,12 +26,16 @@ function matchSnapshot(readSnapshot, assert, name, serialized) {
   nameCounts.set(name, count)
   const escaped = escapeSnapshot(serialized)
   const key = `${name} ${count}`
-  const makeEntry = (x) => `\nexports[\`${escapeSnapshot(key)}\`] = \`${x}\`;\n`
-  const fixedText = escaped.includes('\r') ? snapshotText : snapshotTextClean // well, if we expect \r let's preserve them
-  const final = escaped.includes('\n') ? `\n${escaped}\n` : escaped
-  if (fixedText.includes(makeEntry(final))) return
-  // Perhaps wrapped with newlines from Node.js snapshots?
-  if (!final.includes('\n') && fixedText.includes(makeEntry(`\n${final}\n`))) return
+  // Node.js and jest escape keys differently, both result to same strings, accept both
+  for (const keyfun of [escapeSnapshot, escapeSnapshotKey]) {
+    const makeEntry = (x) => `\nexports[\`${keyfun(key)}\`] = \`${x}\`;\n`
+    const fixedText = escaped.includes('\r') ? snapshotText : snapshotTextClean // well, if we expect \r let's preserve them
+    const final = escaped.includes('\n') ? `\n${escaped}\n` : escaped
+    if (fixedText.includes(makeEntry(final))) return
+    // Perhaps wrapped with newlines from Node.js snapshots?
+    if (!final.includes('\n') && fixedText.includes(makeEntry(`\n${final}\n`))) return
+  }
+
   return assert.fail(`Could not match "${key}" in snapshot. ${addFail}`)
 }
 

tests/node/snapshot.test.js

@@ -0,0 +1,155 @@
+import { describe, it } from 'node:test'
+import * as nodeTest from 'node:test'
+
+const skip = !nodeTest.snapshot // Node.js 20.x and 22.12 (22.13 has it)
+const wrongSerialization = process.env.EXODUS_TEST_PLATFORM === 'xs' // https://github.com/Moddable-OpenSource/moddable/issues/1564
+
+it('simple', { skip: skip || wrongSerialization }, (t) => {
+  t.assert.snapshot(10)
+  t.assert.snapshot(null)
+  t.assert.snapshot()
+  t.assert.snapshot([])
+  t.assert.snapshot(/xx/)
+  t.assert.snapshot(Infinity)
+  t.assert.snapshot(false)
+  t.assert.snapshot(true)
+  t.assert.snapshot({})
+})
+
+it('complex', { skip: skip || wrongSerialization }, (t) => {
+  t.assert.snapshot([10])
+  t.assert.snapshot([{ a: 10 }])
+  t.assert.snapshot({ a: 10 })
+  t.assert.snapshot({ a: 10, b: 20 })
+  t.assert.snapshot(Buffer.from(''))
+})
+
+// repeat test name
+it('simple', { skip: skip || wrongSerialization }, (t) => {
+  t.assert.snapshot(/hello/)
+  t.assert.snapshot(true)
+  t.assert.snapshot(NaN)
+  t.assert.snapshot({})
+  t.assert.snapshot(42)
+  t.assert.snapshot([])
+  t.assert.snapshot(-Infinity)
+})
+
+it('mixed', { skip: skip || wrongSerialization }, (t) => {
+  t.assert.snapshot(true)
+  t.assert.snapshot([1, 2, 3])
+  t.assert.snapshot({ foo: 'bar' })
+  t.assert.snapshot(43)
+  t.assert.snapshot({})
+  t.assert.snapshot([])
+})
+
+// repeat test name
+it('mixed', { skip: skip || wrongSerialization }, (t) => {
+  t.assert.snapshot([5, 4, 3])
+  t.assert.snapshot([])
+  t.assert.snapshot(false)
+  t.assert.snapshot(41)
+  t.assert.snapshot({ bar: 'buz' })
+  t.assert.snapshot({})
+})
+
+it('escape', { skip }, (t) => {
+  t.assert.snapshot('\\')
+  t.assert.snapshot('${')
+  t.assert.snapshot('$$\\${')
+})
+
+const TEST_ONE = { a: 20, d: Buffer.from('foo'), b: [1, 2, 'bar', 5], e: { foo: 'bar' } }
+// eslint-disable-next-line no-sparse-arrays
+const TEST_TWO = { ['__proto__']: [], b: [1, 2, , , 5], e: { foo: 'bar' }, f: -Infinity }
+const TEST_THREE = [new Error('?!'), new TypeError('bar'), new Uint16Array([4, 2, 65_123]), null]
+
+// Test names repeat on a purpose!
+
+it('test A', { skip }, (t) => {
+  t.assert.snapshot(TEST_ONE)
+})
+
+it('test B', { skip: skip || wrongSerialization }, (t) => {
+  t.assert.snapshot(TEST_TWO)
+})
+
+it('test B', { skip: skip || wrongSerialization }, (t) => {
+  t.assert.snapshot(TEST_THREE)
+})
+
+// Repeat name
+it('test B', { skip: skip || wrongSerialization }, (t) => {
+  t.assert.snapshot({ x: 1337 })
+})
+
+describe('nested test', { skip }, () => {
+  it('test A', { skip: wrongSerialization }, (t) => {
+    t.assert.snapshot(TEST_TWO)
+  })
+
+  it('test A', { skip: wrongSerialization }, (t) => {
+    t.assert.snapshot(TEST_THREE)
+  })
+
+  it('nested test one', (t) => {
+    t.assert.snapshot(TEST_ONE)
+  })
+})
+
+describe('weird  names', { skip }, () => {
+  const ascii = Array.from({ length: 128 })
+    .fill()
+    .map((a, i) => i)
+    .slice(0x20)
+    .map((i) => String.fromCodePoint(i))
+    .join('')
+  for (const key of [
+    '\n',
+    '{}',
+    '$',
+    '`',
+    '>',
+    '` ` `',
+    '` `\n `',
+    '\\',
+    '\\\n`\n\\``',
+    '${',
+    ascii,
+  ]) {
+    it(key, (t) => {
+      t.assert.snapshot(key)
+    })
+  }
+
+  it('multi\nline', { skip }, (t) => {
+    t.assert.snapshot(0)
+  })
+
+  it('with `', { skip }, (t) => {
+    t.assert.snapshot(42)
+  })
+})
+
+describe('', { skip }, () => {
+  it('', (t) => {
+    t.assert.snapshot('empty names test')
+    t.assert.snapshot(t.fullName)
+    t.assert.snapshot(t.name)
+  })
+
+  it((t) => {
+    t.assert.snapshot('no name test')
+    t.assert.snapshot(t.fullName)
+    t.assert.snapshot(t.name)
+  })
+
+  // non-string names
+  for (const name of [false, true, 0, 1, null, undefined, {}, ['arr'], 'str']) {
+    it(name, (t) => {
+      t.assert.snapshot(t.fullName)
+      t.assert.snapshot(t.name)
+    })
+  }
+})