Comments in test file throws exception when writing inline snapshots

[MrOrz]

🐛 Bug Report

When a test file

• has comments
• has empty toMatchInlineSnapshot()

Running jest will fail when prettier tries to prettify the file with updated snapshot.

Test file:

//
it('comment + inlinesnapshot breaks jest', () => {
  expect(true).toMatchInlineSnapshot();
});

Test result:

$ npm t -- typescript.test.ts

> snapshot-comment-error@1.0.0 test /Users/johnsonliang/workspace/snapshot-comment-error
> jest "typescript.test.ts"

 FAIL  ./typescript.test.ts
  ● Test suite failed to run

    TypeError: Property comments[0] of File expected node to be of a type ["Comment"] but instead got "Line"

      at validate (node_modules/@babel/types/lib/definitions/utils.js:132:11)
      at Object.validator [as validate] (node_modules/@babel/types/lib/definitions/utils.js:103:7)
      at validateField (node_modules/@babel/types/lib/validators/validate.js:24:9)
      at validate (node_modules/@babel/types/lib/validators/validate.js:17:3)
      at builder (node_modules/@babel/types/lib/builders/builder.js:38:27)
      at File (node_modules/@babel/types/lib/builders/generated/index.js:318:31)
      at Object.parse (node_modules/prettier/index.js:11370:19)
      at coreFormat (node_modules/prettier/index.js:14784:25)

Test Suites: 1 failed, 1 total
Tests:       0 total
Snapshots:   0 total
Time:        1.13 s, estimated 3 s
Ran all test suites matching /typescript.test.ts/i.
npm ERR! Test failed.  See above for more details.

To Reproduce

Steps to reproduce the behavior:

$ git clone git@github.com:MrOrz/tsjest-comment-error.git
$ cd tsjest-comment-error
$ npm i
$ npm t

Observations:

• The repo includes javascript.test.js and typescript.test.ts with identical code.
  • It's only reproducible in typescript files: When running npm t, javascript.test.js can have its snapshot successfully updated, while typescript.test.ts fails.
• Moving the comment in typescript.test.ts to any location can still trigger the exception
  • Not only at the end of the file. Maybe a different issue from Single-line comments existing as the final line for imported (typescript) files results in a syntax error #1730 .
• The test passes if and only if we remove all comment lines from typescript.test.ts

Expected behavior

Snapshot in test files gets updated.

Link to repo (highly encouraged)

https://github.com/MrOrz/tsjest-comment-error

Debug log:

# content of ts-jest.log :
{"context":{"allowJs":false,"logLevel":20,"namespace":"jest-preset","package":"ts-jest","version":"26.1.1"},"message":"creating jest presets not handling JavaScript files","sequence":1,"time":"2020-06-23T03:51:05.137Z"}
{"context":{"logLevel":20,"namespace":"Importer","package":"ts-jest","version":"26.1.1"},"message":"creating Importer singleton","sequence":2,"time":"2020-06-23T03:51:07.556Z"}
{"context":{"allowJs":false,"logLevel":20,"namespace":"jest-preset","package":"ts-jest","version":"26.1.1"},"message":"creating jest presets not handling JavaScript files","sequence":3,"time":"2020-06-23T03:51:07.563Z"}
{"context":{"actualVersion":"26.0.1","expectedVersion":">=26 <27","logLevel":20,"namespace":"versions","package":"ts-jest","version":"26.1.1"},"message":"checking version of jest: OK","sequence":4,"time":"2020-06-23T03:51:07.565Z"}
{"context":{"baseOptions":{},"logLevel":20,"namespace":"jest-transformer","package":"ts-jest","transformerId":1,"version":"26.1.1"},"message":"created new transformer","sequence":5,"time":"2020-06-23T03:51:07.565Z"}
{"context":{"fileName":"/Users/johnsonliang/workspace/snapshot-comment-error/typescript.test.ts","logLevel":20,"namespace":"jest-transformer","package":"ts-jest","transformOptions":{"config":{"automock":false,"cache":true,"cacheDirectory":"/private/var/folders/r4/whpnz2j55p72y0brmr1f3rdr0000gn/T/jest_dx","clearMocks":false,"coveragePathIgnorePatterns":["/node_modules/"],"cwd":"/Users/johnsonliang/workspace/snapshot-comment-error","detectLeaks":false,"detectOpenHandles":false,"errorOnDeprecated":false,"extraGlobals":[],"forceCoverageMatch":[],"globals":{},"haste":{"computeSha1":false,"throwOnModuleCollision":false},"moduleDirectories":["node_modules"],"moduleFileExtensions":["js","json","jsx","ts","tsx","node"],"moduleNameMapper":[],"modulePathIgnorePatterns":[],"name":"a715305738be4fcdea2147c3ce6123dc","prettierPath":"prettier","resetMocks":false,"resetModules":false,"restoreMocks":false,"rootDir":"/Users/johnsonliang/workspace/snapshot-comment-error","roots":["/Users/johnsonliang/workspace/snapshot-comment-error"],"runner":"jest-runner","setupFiles":[],"setupFilesAfterEnv":[],"skipFilter":false,"snapshotSerializers":[],"testEnvironment":"/Users/johnsonliang/workspace/snapshot-comment-error/node_modules/jest-environment-node/build/index.js","testEnvironmentOptions":{},"testLocationInResults":false,"testMatch":["**/__tests__/**/*.[jt]s?(x)","**/?(*.)+(spec|test).[tj]s?(x)"],"testPathIgnorePatterns":["/node_modules/"],"testRegex":[],"testRunner":"/Users/johnsonliang/workspace/snapshot-comment-error/node_modules/jest-jasmine2/build/index.js","testURL":"http://localhost","timers":"real","transform":[["^.+\\.tsx?$","/Users/johnsonliang/workspace/snapshot-comment-error/node_modules/ts-jest/dist/index.js",{}]],"transformIgnorePatterns":["/node_modules/"],"watchPathIgnorePatterns":[]},"instrument":false,"rootDir":"/Users/johnsonliang/workspace/snapshot-comment-error","supportsDynamicImport":false,"supportsStaticESM":false},"transformerId":1,"version":"26.1.1"},"message":"computing cache key for /Users/johnsonliang/workspace/snapshot-comment-error/typescript.test.ts","sequence":6,"time":"2020-06-23T03:51:07.566Z"}
{"context":{"logLevel":30,"namespace":"jest-transformer","package":"ts-jest","transformerId":1,"version":"26.1.1"},"message":"no matching config-set found, creating a new one","sequence":7,"time":"2020-06-23T03:51:07.566Z"}
{"context":{"config":{"automock":false,"cache":true,"cacheDirectory":"/private/var/folders/r4/whpnz2j55p72y0brmr1f3rdr0000gn/T/jest_dx","clearMocks":false,"coveragePathIgnorePatterns":["/node_modules/"],"cwd":"/Users/johnsonliang/workspace/snapshot-comment-error","detectLeaks":false,"detectOpenHandles":false,"errorOnDeprecated":false,"extraGlobals":[],"forceCoverageMatch":[],"globals":{},"haste":{"computeSha1":false,"throwOnModuleCollision":false},"moduleDirectories":["node_modules"],"moduleFileExtensions":["js","json","jsx","ts","tsx","node"],"moduleNameMapper":[],"modulePathIgnorePatterns":[],"name":"a715305738be4fcdea2147c3ce6123dc","prettierPath":"prettier","resetMocks":false,"resetModules":false,"restoreMocks":false,"rootDir":"/Users/johnsonliang/workspace/snapshot-comment-error","roots":["/Users/johnsonliang/workspace/snapshot-comment-error"],"runner":"jest-runner","setupFiles":[],"setupFilesAfterEnv":[],"skipFilter":false,"snapshotSerializers":[],"testEnvironment":"/Users/johnsonliang/workspace/snapshot-comment-error/node_modules/jest-environment-node/build/index.js","testEnvironmentOptions":{},"testLocationInResults":false,"testMatch":["**/__tests__/**/*.[jt]s?(x)","**/?(*.)+(spec|test).[tj]s?(x)"],"testPathIgnorePatterns":["/node_modules/"],"testRegex":[],"testRunner":"/Users/johnsonliang/workspace/snapshot-comment-error/node_modules/jest-jasmine2/build/index.js","testURL":"http://localhost","timers":"real","transform":[["^.+\\.tsx?$","/Users/johnsonliang/workspace/snapshot-comment-error/node_modules/ts-jest/dist/index.js",{}]],"transformIgnorePatterns":["/node_modules/"],"watchPathIgnorePatterns":[]},"logLevel":20,"namespace":"backports","package":"ts-jest","transformerId":1,"version":"26.1.1"},"message":"backporting config","sequence":8,"time":"2020-06-23T03:51:07.566Z"}

envinfo

System:
    OS: Mac OSX

Npm packages:
    jest: 26.0.1
    ts-jest: 26.1.1
    typescript: 3.9.5
    prettier: 2.0.5
    babel(optional): 

[MrOrz]

As a workaround, I use multiline strings as a replacement of multiline comments in my test files. Works like a charm lol

#wisdomFromPython

[ahnpnl]

The stacktrace throws out is the one from Babel core. This is not ts-jest issue :)

You should create an issue for jest team.

[MrOrz]

You should create an issue for jest team.

Thanks for the quick response!

I am afraid that it is not jest's issue, because it is not reproducible in jest & JS files. Only the combination of ts-jest & typescript test files triggers this issue.

[ahnpnl]

Updated: I checked your repo, actually you don't use babel-jest. But still the error is caused by babel-jest cannot handle the compiled output. This is the compiled output of typescript.test.ts

//
it('comment + inlinesnapshot breaks jest', function () {
    expect(true).toMatchInlineSnapshot();
});
//# sourceMappingURL=data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJmaWxlIjoiL1VzZXJzL2Fobi90c2plc3QtY29tbWVudC1lcnJvci90eXBlc2NyaXB0LnRlc3QudHMiLCJzb3VyY2VzIjpbIi9Vc2Vycy9haG4vdHNqZXN0LWNvbW1lbnQtZXJyb3IvdHlwZXNjcmlwdC50ZXN0LnRzIl0sIm5hbWVzIjpbXSwibWFwcGluZ3MiOiJBQUFBLEVBQUU7QUFDRixFQUFFLENBQUMsc0NBQXNDLEVBQUU7SUFDekMsTUFBTSxDQUFDLElBQUksQ0FBQyxDQUFDLHFCQUFxQixFQUFFLENBQUM7QUFDdkMsQ0FBQyxDQUFDLENBQUMiLCJzb3VyY2VzQ29udGVudCI6WyIvL1xuaXQoJ2NvbW1lbnQgKyBpbmxpbmVzbmFwc2hvdCBicmVha3MgamVzdCcsICgpID0

as you can see the compile output is similar to the original code. The error stack points to jest because it somehow cannot handle this output

[meyer]

I’m running into this same issue. Looks like it’s being tracked here: jestjs/jest#10208

[meyer]

here’s the fix: babel/babel#11752