Improve tests following lint advice from eslint-node-test

eslint.config.js

@@ -3,6 +3,7 @@ import esLintjs from '@eslint/js';
 import { defineConfig } from 'eslint/config';
 import tseslint from 'typescript-eslint';
 import prettier from 'eslint-config-prettier';
+import nodeTest from 'eslint-node-test';
 
 // Only run tseslint on the files that we have included for TypeScript.
 const tsconfigTsFiles = ['**/*.{ts,mts}']; // match "include" in tsconfig.ts.json;
@@ -65,4 +66,17 @@ export default defineConfig(
       ],
     },
   },
+  {
+    files: ['**/*.js'],
+    plugins: {
+      'node-test': nodeTest,
+    },
+    extends: ['node-test/recommended'],
+    rules: {
+      'node-test/prefer-test-context-assert': 'off', // we use callback parameter t to generate mocks, but do not want to use t.assertX (as t.assertX not automatically strict)
+      'node-test/no-useless-assertion': 'off', // we use `assert.doesNotThrow()` as only assert in multiple tests (so removing that assert triggers a different lint error)
+      'node-test/no-process-env-mutation': 'off', // we manage env in ways node-test does not recognise
+      'node-test/require-top-level-describe': 'error', // Enforce top-level describe for providing context in test output. Disable by hand on single test files.
+    },
+  },
 );

examples/help-centered.mjs

@@ -25,8 +25,6 @@ class MyCommand extends Command {
 
 const program = new MyCommand();
 
-program.configureHelp({ MyCommand });
-
 program
   .option('-s', 'short flag')
   .option('-f, --flag', 'short and long flag')

package.json

@@ -50,6 +50,7 @@
     "@types/node": "^22.7.4",
     "eslint": "^10.0.2",
     "eslint-config-prettier": "^10.0.1",
+    "eslint-node-test": "^0.4.0",
     "globals": "^17.3.0",
     "prettier": "^3.2.5",
     "tsd": "^0.33.0",

tests/argument.choices.test.js

@@ -22,9 +22,12 @@ describe('Argument.choices()', () => {
     program.addArgument(
       new commander.Argument('<shade>').choices(['red', 'blue']),
     );
-    assert.throws(() => {
-      program.parse(['orange'], { from: 'user' });
-    });
+    assert.throws(
+      () => {
+        program.parse(['orange'], { from: 'user' });
+      },
+      { code: 'commander.invalidArgument' },
+    );
   });
 });
 
@@ -50,8 +53,11 @@ describe('Argument.choices() parameter is treated as readonly, per TypeScript de
     const param = ['red', 'blue'];
     program.addArgument(new commander.Argument('<shade>').choices(param));
     param.push('orange');
-    assert.throws(() => {
-      program.parse(['orange'], { from: 'user' });
-    });
+    assert.throws(
+      () => {
+        program.parse(['orange'], { from: 'user' });
+      },
+      { code: 'commander.invalidArgument' },
+    );
   });
 });

tests/argument.custom-processing.test.js

@@ -171,7 +171,7 @@ describe('custom processing function for command-argument', () => {
     const program = new commander.Command();
     assert.throws(() => {
       program.argument('<number>', 'float argument', 4);
-    });
+    }, /a default value for a required argument is never used/);
   });
 
   test('when custom processing for argument throws plain error then not CommanderError caught', () => {

tests/argument.variadic.test.js

@@ -4,7 +4,7 @@ import assert from 'node:assert/strict';
 
 // Testing variadic arguments. Testing all the action arguments, but could test just variadicArg.
 
-describe('Command variadic argument using .argument()', (t) => {
+describe('Command variadic argument using .argument()', () => {
   test('when no extra arguments specified for program then variadic arg is empty array', (t) => {
     const actionMock = t.mock.fn();
     const program = new commander.Command();
@@ -117,17 +117,4 @@ describe('Command variadic argument using .argument()', (t) => {
     program.parse(['one', 'two'], { from: 'user' });
     assert.deepEqual(passedArg, ['one', 'two']);
   });
-
-  test('when variadic has default array then specified value is used instead of default (not appended)', () => {
-    const program = new commander.Command();
-    let passedArg;
-    program
-      .addArgument(new commander.Argument('[value...]').default(['DEFAULT']))
-      .action((value) => {
-        passedArg = value;
-      });
-
-    program.parse(['one', 'two'], { from: 'user' });
-    assert.deepEqual(passedArg, ['one', 'two']);
-  });
 });

tests/command.action.test.js

@@ -54,9 +54,12 @@ describe('Command.action()', () => {
       test(`via ${methodName}`, (t) => {
         const actionMock = t.mock.fn();
         program.action(actionMock);
-        assert.throws(() => {
-          program.parse(['node', 'test']);
-        });
+        assert.throws(
+          () => {
+            program.parse(['node', 'test']);
+          },
+          { code: 'commander.missingArgument' },
+        );
         assert.equal(actionMock.mock.callCount(), 0);
       });
     });

tests/command.addCommand.test.js

@@ -36,6 +36,7 @@ describe('Command.addCommand()', () => {
         case 'number':
         case 'undefined':
           // Compare values in a way that will be readable in test failure message.
+          // eslint-disable-next-line node-test/no-conditional-assertion
           assert.equal(`${key}:${cmd1[key]}`, `${key}:${cmd2[key]}`);
           break;
       }
@@ -47,7 +48,7 @@ describe('Command.addCommand()', () => {
     const cmd = new commander.Command();
     assert.throws(() => {
       program.addCommand(cmd);
-    });
+    }, /Command passed to \.addCommand\(\) must have a name/);
   });
 
   test('when executable command with custom executableFile passed to .addCommand then ok', () => {

tests/command.addHelpText.test.js

@@ -97,7 +97,7 @@ describe('Command.addHelpText(): program calls to addHelpText', () => {
     const program = new commander.Command();
     assert.throws(() => {
       program.addHelpText('silly', 'text');
-    });
+    }, /Unexpected value for position to addHelpText/);
   });
 });
 
@@ -157,18 +157,24 @@ describe('Command.addHelpText(): context checks with full parse', () => {
   test('when help requested then text is on stdout', () => {
     const program = new commander.Command();
     program.exitOverride().addHelpText('before', 'text');
-    assert.throws(() => {
-      program.parse(['--help'], { from: 'user' });
-    });
+    assert.throws(
+      () => {
+        program.parse(['--help'], { from: 'user' });
+      },
+      { code: 'commander.helpDisplayed' },
+    );
     assert.equal(stdoutSpy.mock.calls[0].arguments[0], 'text\n');
   });
 
   test('when help for error then text is on stderr', () => {
     const program = new commander.Command();
     program.exitOverride().addHelpText('before', 'text').command('sub');
-    assert.throws(() => {
-      program.parse([], { from: 'user' });
-    });
+    assert.throws(
+      () => {
+        program.parse([], { from: 'user' });
+      },
+      { code: 'commander.help' },
+    );
     assert.equal(stderrSpy.mock.calls[0].arguments[0], 'text\n');
   });
 
@@ -178,9 +184,12 @@ describe('Command.addHelpText(): context checks with full parse', () => {
     program.exitOverride().addHelpText('before', (contextParam) => {
       context = contextParam;
     });
-    assert.throws(() => {
-      program.parse(['--help'], { from: 'user' });
-    });
+    assert.throws(
+      () => {
+        program.parse(['--help'], { from: 'user' });
+      },
+      { code: 'commander.helpDisplayed' },
+    );
     assert.equal(context.error, false);
   });
 
@@ -193,9 +202,12 @@ describe('Command.addHelpText(): context checks with full parse', () => {
         context = contextParam;
       })
       .command('sub');
-    assert.throws(() => {
-      program.parse([], { from: 'user' });
-    });
+    assert.throws(
+      () => {
+        program.parse([], { from: 'user' });
+      },
+      { code: 'commander.help' },
+    );
     assert.equal(context.error, true);
   });
 
@@ -205,9 +217,12 @@ describe('Command.addHelpText(): context checks with full parse', () => {
     program.exitOverride().addHelpText('before', (contextParam) => {
       context = contextParam;
     });
-    assert.throws(() => {
-      program.parse(['--help'], { from: 'user' });
-    });
+    assert.throws(
+      () => {
+        program.parse(['--help'], { from: 'user' });
+      },
+      { code: 'commander.helpDisplayed' },
+    );
     assert.equal(context.command, program);
   });
 
@@ -218,9 +233,12 @@ describe('Command.addHelpText(): context checks with full parse', () => {
     const sub = program.command('sub').addHelpText('before', (contextParam) => {
       context = contextParam;
     });
-    assert.throws(() => {
-      program.parse(['sub', '--help'], { from: 'user' });
-    });
+    assert.throws(
+      () => {
+        program.parse(['sub', '--help'], { from: 'user' });
+      },
+      { code: 'commander.helpDisplayed' },
+    );
     assert.equal(context.command, sub);
   });
 
@@ -231,9 +249,12 @@ describe('Command.addHelpText(): context checks with full parse', () => {
       context = contextParam;
     });
     const sub = program.command('sub');
-    assert.throws(() => {
-      program.parse(['sub', '--help'], { from: 'user' });
-    });
+    assert.throws(
+      () => {
+        program.parse(['sub', '--help'], { from: 'user' });
+      },
+      { code: 'commander.helpDisplayed' },
+    );
     assert.equal(context.command, sub);
   });
 });