test: Check the context line seen through n steps after calling setContextLineNumber

Author: Dailyscat

test/fixtures/debugger/twenty-lines.js

@@ -0,0 +1,20 @@
+let x = 0;
+x = 1;
+x = 2;
+x = 3;
+x = 4;
+x = 5;
+x = 6;
+x = 7;
+x = 8;
+x = 9;
+x = 10;
+x = 11;
+x = 12;
+x = 13;
+x = 14;
+x = 15;
+x = 16;
+x = 17;
+x = 18;
+module.exports = x;

test/sequential/test-debugger-set-context-line-number.mjs

@@ -0,0 +1,46 @@
+import { skipIfInspectorDisabled } from '../common/index.mjs';
+skipIfInspectorDisabled();
+
+import { path } from '../common/fixtures.mjs';
+import startCLI from '../common/debugger.js';
+
+import assert from 'assert';
+
+const script = path('debugger', 'twenty-lines.js');
+const cli = startCLI([script]);
+
+function onFatal(error) {
+  cli.quit();
+  throw error;
+}
+
+function getLastline(output) {
+  const splitedByLine = output.split('\n');
+  return splitedByLine[splitedByLine.length - 2];
+}
+
+// Stepping through breakpoints.
+try {
+  await cli.waitForInitialBreak();
+  await cli.waitForPrompt();
+
+  // Make sure the initial value is 2.
+  await cli.stepCommand('n');
+  assert.ok(getLastline(cli.output).includes('4 x = 3;'));
+
+  await cli.command('setContextLineNumber(5)');
+  await cli.stepCommand('n');
+  assert.ok(getLastline(cli.output).includes('8 x = 7;'));
+
+  await cli.command('setContextLineNumber(3)');
+  await cli.stepCommand('n');
+  assert.ok(getLastline(cli.output).includes('7 x = 6;'));
+
+  await cli.command('list(3)');
+  await cli.stepCommand('n');
+  assert.ok(getLastline(cli.output).includes('7 x = 6;'));
+
+  await cli.quit();
+} catch (error) {
+  onFatal(error);
+}