test: add tests for REPL custom evals

dario-piotrowicz · targos · commit 704b1fa075b6 · 2025-06-16T08:52:18.000+02:00
this commit reintroduces the REPL custom eval tests that have been introduced in #57691 but reverted in #57793 the tests turned out problematic before because `getReplOutput`, the function used to return the repl output wasn't taking into account that input processing and output emitting are asynchronous operation can resolve with a small delay the new implementation here replaces `getReplOutput` with `getReplRunOutput` that resolves repl inputs by running them and using the repl prompt as an indicator to when the input processing has completed PR-URL: #57850 Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
diff --git a/lib/repl.js b/lib/repl.js
@@ -310,7 +310,6 @@ function REPLServer(prompt,
 options.useColors = shouldColorize(options.output);
 }
 
- // TODO(devsnek): Add a test case for custom eval functions.
 const preview = options.terminal &&
 (options.preview !== undefined ? !!options.preview : !eval_);
 
diff --git a/test/parallel/test-repl-custom-eval-previews.js b/test/parallel/test-repl-custom-eval-previews.js
@@ -0,0 +1,101 @@
+'use strict';
+
+const common = require('../common');
+const ArrayStream = require('../common/arraystream');
+const assert = require('assert');
+const { describe, it } = require('node:test');
+
+common.skipIfInspectorDisabled();
+
+const repl = require('repl');
+
+const testingReplPrompt = '_REPL_TESTING_PROMPT_>';
+
+// Processes some input in a REPL instance and returns a promise that
+// resolves to the produced output (as a string).
+function getReplRunOutput(input, replOptions) {
+ return new Promise((resolve) => {
+ const inputStream = new ArrayStream();
+ const outputStream = new ArrayStream();
+
+ const replServer = repl.start({
+ input: inputStream,
+ output: outputStream,
+ prompt: testingReplPrompt,
+ ...replOptions,
+ });
+
+ let output = '';
+
+ outputStream.write = (chunk) => {
+ output += chunk;
+ // The prompt appears after the input has been processed
+ if (output.includes(testingReplPrompt)) {
+ replServer.close();
+ resolve(output);
+ }
+ };
+
+ inputStream.emit('data', input);
+
+ inputStream.run(['']);
+ });
+}
+
+describe('with previews', () => {
+ it("doesn't show previews by default", async () => {
+ const input = "'Hello custom' + ' eval World!'";
+ const output = await getReplRunOutput(
+ input,
+ {
+ terminal: true,
+ eval: (code, _ctx, _replRes, cb) => cb(null, eval(code)),
+ },
+ );
+ const lines = getSingleCommandLines(output);
+ assert.match(lines.command, /^'Hello custom' \+ ' eval World!'/);
+ assert.match(lines.prompt, new RegExp(`${testingReplPrompt}$`));
+ assert.strictEqual(lines.result, "'Hello custom eval World!'");
+ assert.strictEqual(lines.preview, undefined);
+ });
+
+ it('does show previews if `preview` is set to `true`', async () => {
+ const input = "'Hello custom' + ' eval World!'";
+ const output = await getReplRunOutput(
+ input,
+ {
+ terminal: true,
+ eval: (code, _ctx, _replRes, cb) => cb(null, eval(code)),
+ preview: true,
+ },
+ );
+ const lines = getSingleCommandLines(output);
+ assert.match(lines.command, /^'Hello custom' \+ ' eval World!'/);
+ assert.match(lines.prompt, new RegExp(`${testingReplPrompt}$`));
+ assert.strictEqual(lines.result, "'Hello custom eval World!'");
+ assert.match(lines.preview, /'Hello custom eval World!'/);
+ });
+});
+
+function getSingleCommandLines(output) {
+ const outputLines = output.split('\n');
+
+ // The first line contains the command being run
+ const command = outputLines.shift();
+
+ // The last line contains the prompt (asking for some new input)
+ const prompt = outputLines.pop();
+
+ // The line before the last one contains the result of the command
+ const result = outputLines.pop();
+
+ // The line before that contains the preview of the command
+ const preview = outputLines.shift();
+
+ return {
+ command,
+ prompt,
+ result,
+ preview,
+ };
+}
diff --git a/test/parallel/test-repl-custom-eval.js b/test/parallel/test-repl-custom-eval.js
@@ -0,0 +1,121 @@
+'use strict';
+
+require('../common');
+const ArrayStream = require('../common/arraystream');
+const assert = require('assert');
+const { describe, it } = require('node:test');
+
+const repl = require('repl');
+
+// Processes some input in a REPL instance and returns a promise that
+// resolves to the produced output (as a string).
+function getReplRunOutput(input, replOptions) {
+ return new Promise((resolve) => {
+ const inputStream = new ArrayStream();
+ const outputStream = new ArrayStream();
+
+ const testingReplPrompt = '_REPL_TESTING_PROMPT_>';
+
+ const replServer = repl.start({
+ input: inputStream,
+ output: outputStream,
+ prompt: testingReplPrompt,
+ ...replOptions,
+ });
+
+ let output = '';
+
+ outputStream.write = (chunk) => {
+ output += chunk;
+ // The prompt appears after the input has been processed
+ if (output.includes(testingReplPrompt)) {
+ replServer.close();
+ resolve(output);
+ }
+ };
+
+ inputStream.emit('data', input);
+
+ inputStream.run(['']);
+ });
+}
+
+describe('repl with custom eval', { concurrency: true }, () => {
+ it('uses the custom eval function as expected', async () => {
+ const output = await getReplRunOutput('Convert this to upper case', {
+ terminal: true,
+ eval: (code, _ctx, _replRes, cb) => cb(null, code.toUpperCase()),
+ });
+ assert.match(
+ output,
+ /Convert this to upper case\r\n'CONVERT THIS TO UPPER CASE\\n'/
+ );
+ });
+
+ it('surfaces errors as expected', async () => {
+ const output = await getReplRunOutput('Convert this to upper case', {
+ terminal: true,
+ eval: (_code, _ctx, _replRes, cb) => cb(new Error('Testing Error')),
+ });
+ assert.match(output, /Uncaught Error: Testing Error\n/);
+ });
+
+ it('provides a repl context to the eval callback', async () => {
+ const context = await new Promise((resolve) => {
+ const r = repl.start({
+ eval: (_cmd, context) => resolve(context),
+ });
+ r.context = { foo: 'bar' };
+ r.write('\n.exit\n');
+ });
+ assert.strictEqual(context.foo, 'bar');
+ });
+
+ it('provides the global context to the eval callback', async () => {
+ const context = await new Promise((resolve) => {
+ const r = repl.start({
+ useGlobal: true,
+ eval: (_cmd, context) => resolve(context),
+ });
+ global.foo = 'global_foo';
+ r.write('\n.exit\n');
+ });
+
+ assert.strictEqual(context.foo, 'global_foo');
+ delete global.foo;
+ });
+
+ it('inherits variables from the global context but does not use it afterwords if `useGlobal` is false', async () => {
+ global.bar = 'global_bar';
+ const context = await new Promise((resolve) => {
+ const r = repl.start({
+ useGlobal: false,
+ eval: (_cmd, context) => resolve(context),
+ });
+ global.baz = 'global_baz';
+ r.write('\n.exit\n');
+ });
+
+ assert.strictEqual(context.bar, 'global_bar');
+ assert.notStrictEqual(context.baz, 'global_baz');
+ delete global.bar;
+ delete global.baz;
+ });
+
+ /**
+ * Default preprocessor transforms
+ * function f() {} to
+ * var f = function f() {}
+ * This test ensures that original input is preserved.
+ * Reference: https://github.com/nodejs/node/issues/9743
+ */
+ it('preserves the original input', async () => {
+ const cmd = await new Promise((resolve) => {
+ const r = repl.start({
+ eval: (cmd) => resolve(cmd),
+ });
+ r.write('function f() {}\n.exit\n');
+ });
+ assert.strictEqual(cmd, 'function f() {}\n');
+ });
+});
diff --git a/test/parallel/test-repl-eval.js b/test/parallel/test-repl-eval.js

Original file line number	Diff line number	Diff line change
`@@ -310,7 +310,6 @@ function REPLServer(prompt,`
`310`	`310`	`options.useColors=shouldColorize(options.output);`
`311`	`311`	`}`
`312`	`312`
`313`		`-// TODO(devsnek): Add a test case for custom eval functions.`
`314`	`313`	`constpreview=options.terminal&&`
`315`	`314`	`(options.preview!==undefined ? !!options.preview : !eval_);`
`316`	`315`
-Original file line number
+Diff line change
@@ @@ -0,0 +1,101 @@ @@
 +'use strict';
++
 +constcommon=require('../common');
 +constArrayStream=require('../common/arraystream');
 +constassert=require('assert');
 +const{ describe, it }=require('node:test');
++
 +common.skipIfInspectorDisabled();
++
 +constrepl=require('repl');
++
 +consttestingReplPrompt='_REPL_TESTING_PROMPT_>';
++
 +// Processes some input in a REPL instance and returns a promise that
 +// resolves to the produced output (as a string).
 +functiongetReplRunOutput(input,replOptions){
 +returnnewPromise((resolve)=>{
 +constinputStream=newArrayStream();
 +constoutputStream=newArrayStream();
++
 +constreplServer=repl.start({
 +input: inputStream,
 +output: outputStream,
 +prompt: testingReplPrompt,
 + ...replOptions,
 +});
++
 +letoutput='';
++
 +outputStream.write=(chunk)=>{
 +output+=chunk;
 +// The prompt appears after the input has been processed
 +if(output.includes(testingReplPrompt)){
 +replServer.close();
 +resolve(output);
 +}
 +};
++
 +inputStream.emit('data',input);
++
 +inputStream.run(['']);
 +});
 +}
++
 +describe('with previews',()=>{
 +it("doesn't show previews by default",async()=>{
 +constinput="'Hello custom' + ' eval World!'";
 +constoutput=awaitgetReplRunOutput(
 +input,
 +{
 +terminal: true,
 +eval: (code,_ctx,_replRes,cb)=>cb(null,eval(code)),
 +},
 +);
 +constlines=getSingleCommandLines(output);
 +assert.match(lines.command,/^'Hellocustom'\+'evalWorld!'/);
 +assert.match(lines.prompt,newRegExp(`${testingReplPrompt}$`));
 +assert.strictEqual(lines.result,"'Hello custom eval World!'");
 +assert.strictEqual(lines.preview,undefined);
 +});
++
 +it('does show previews if `preview` is set to `true`',async()=>{
 +constinput="'Hello custom' + ' eval World!'";
 +constoutput=awaitgetReplRunOutput(
 +input,
 +{
 +terminal: true,
 +eval: (code,_ctx,_replRes,cb)=>cb(null,eval(code)),
 +preview: true,
 +},
 +);
 +constlines=getSingleCommandLines(output);
 +assert.match(lines.command,/^'Hellocustom'\+'evalWorld!'/);
 +assert.match(lines.prompt,newRegExp(`${testingReplPrompt}$`));
 +assert.strictEqual(lines.result,"'Hello custom eval World!'");
 +assert.match(lines.preview,/'HellocustomevalWorld!'/);
 +});
 +});
++
 +functiongetSingleCommandLines(output){
 +constoutputLines=output.split('\n');
++
 +// The first line contains the command being run
 +constcommand=outputLines.shift();
++
 +// The last line contains the prompt (asking for some new input)
 +constprompt=outputLines.pop();
++
 +// The line before the last one contains the result of the command
 +constresult=outputLines.pop();
++
 +// The line before that contains the preview of the command
 +constpreview=outputLines.shift();
++
 +return{
 + command,
 + prompt,
 + result,
 + preview,
 +};
 +}