feat: add configurable maxBuffer option to runDiffImageToSnapshot (#344)

* feat: add configurable maxBuffer option to runDiffImageToSnapshot

* fixup! feat: add configurable maxBuffer option to runDiffImageToSnapshot

README.md

@@ -124,6 +124,7 @@ See [the examples](./examples/README.md) for more detailed usage or read about a
 * `dumpDiffToConsole`: (default `false`) Will output base64 string of a diff image to console in case of failed tests (in addition to creating a diff image). This string can be copy-pasted to a browser address string to preview the diff for a failed test.
 * `dumpInlineDiffToConsole`: (default `false`) Will output the image to the terminal using iTerm's [Inline Images Protocol](https://iterm2.com/documentation-images.html). If the term is not compatible, it does the same thing as `dumpDiffToConsole`.
 * `allowSizeMismatch`: (default `false`) If set to true, the build will not fail when the screenshots to compare have different sizes.
+* `maxChildProcessBufferSizeInBytes`: (default `10 * 1024 * 1024`) Sets the max number of bytes for stdout/stderr when running `diff-snapshot` in a child process.
 * `runtimeHooksPath`: (default `undefined`) This needs to be set to a existing file, like `require.resolve('./runtimeHooksPath.cjs')`. This file can expose a few hooks:
   * `onBeforeWriteToDisc`: before saving any image to the disc, this function will be called (can be used to write EXIF data to images for instance)
     `onBeforeWriteToDisc: (arguments: { buffer: Buffer; destination: string; testPath: string; currentTestName: string }) => Buffer`

__tests__/__snapshots__/index.spec.js.snap

@@ -48,6 +48,7 @@ exports[`toMatchImageSnapshot passes diffImageToSnapshot everything it needs to
   "diffDirection": "horizontal",
   "failureThreshold": 0,
   "failureThresholdType": "pixel",
+  "maxChildProcessBufferSizeInBytes": 10485760,
   "onlyDiff": false,
   "receivedDir": undefined,
   "receivedImageBuffer": "pretendthisisanimagebuffer",

__tests__/index.spec.js

@@ -448,6 +448,7 @@ describe('toMatchImageSnapshot', () => {
       onlyDiff: false,
       failureThreshold: 0,
       failureThresholdType: 'pixel',
+      maxChildProcessBufferSizeInBytes: 10 * 1024 * 1024,
       receivedDir: undefined,
       receivedImageBuffer: undefined,
       runtimeHooksPath: undefined,
@@ -500,6 +501,7 @@ describe('toMatchImageSnapshot', () => {
       failureThresholdType: 'percent',
       updatePassedSnapshot: true,
       blur: 1,
+      maxChildProcessBufferSizeInBytes: 1024 * 1024,
       comparisonMethod,
     });
     expect.extend({ toMatchImageSnapshot });
@@ -528,6 +530,7 @@ describe('toMatchImageSnapshot', () => {
       updatePassedSnapshot: true,
       failureThreshold: 1,
       failureThresholdType: 'percent',
+      maxChildProcessBufferSizeInBytes: 1024 * 1024,
       comparisonMethod,
     });
     expect(Chalk).toHaveBeenCalledWith({
@@ -590,6 +593,7 @@ describe('toMatchImageSnapshot', () => {
       testPath: path.join('path', 'to', 'test.spec.js'),
       updateSnapshot: false,
       updatePassedSnapshot: false,
+      maxChildProcessBufferSizeInBytes: 10 * 1024 * 1024,
       failureThreshold: 0,
       failureThresholdType: 'pixel',
       comparisonMethod: 'pixelmatch',

src/diff-snapshot.js

@@ -421,7 +421,7 @@ function runDiffImageToSnapshot(options) {
     {
       input: Buffer.from(serializedInput),
       stdio: ['pipe', 'inherit', 'inherit', 'pipe'],
-      maxBuffer: 10 * 1024 * 1024, // 10 MB
+      maxBuffer: options.maxChildProcessBufferSizeInBytes,
     }
   );
 

src/index.js

@@ -151,6 +151,10 @@ function configureToMatchImageSnapshot({
   dumpDiffToConsole: commonDumpDiffToConsole = false,
   dumpInlineDiffToConsole: commonDumpInlineDiffToConsole = false,
   allowSizeMismatch: commonAllowSizeMismatch = false,
+  // Default to 10 MB instead of node's default 1 MB
+  // See https://nodejs.org/api/child_process.html#child_processspawnsynccommand-args-options
+  maxChildProcessBufferSizeInBytes:
+    commonMaxChildProcessBufferSizeInBytes = 10 * 1024 * 1024, // 10 MB
   comparisonMethod: commonComparisonMethod = 'pixelmatch',
 } = {}) {
   return function toMatchImageSnapshot(received, {
@@ -173,6 +177,7 @@ function configureToMatchImageSnapshot({
     dumpDiffToConsole = commonDumpDiffToConsole,
     dumpInlineDiffToConsole = commonDumpInlineDiffToConsole,
     allowSizeMismatch = commonAllowSizeMismatch,
+    maxChildProcessBufferSizeInBytes = commonMaxChildProcessBufferSizeInBytes,
     comparisonMethod = commonComparisonMethod,
   } = {}) {
     const {
@@ -237,6 +242,7 @@ function configureToMatchImageSnapshot({
         updatePassedSnapshot,
         blur,
         allowSizeMismatch,
+        maxChildProcessBufferSizeInBytes,
         comparisonMethod,
         runtimeHooksPath,
       });