test: refactor to avoid reaching outside package

---
type: pre_commit_static_analysis_report
description: Results of running static analysis checks when committing changes.
report:
  - task: lint_filenames
    status: passed
  - task: lint_editorconfig
    status: passed
  - task: lint_markdown
    status: na
  - task: lint_package_json
    status: na
  - task: lint_repl_help
    status: na
  - task: lint_javascript_src
    status: na
  - task: lint_javascript_cli
    status: na
  - task: lint_javascript_examples
    status: na
  - task: lint_javascript_tests
    status: passed
  - task: lint_javascript_benchmarks
    status: na
  - task: lint_python
    status: na
  - task: lint_r
    status: na
  - task: lint_c_src
    status: na
  - task: lint_c_examples
    status: na
  - task: lint_c_benchmarks
    status: na
  - task: lint_c_tests_fixtures
    status: na
  - task: lint_shell
    status: na
  - task: lint_typescript_declarations
    status: na
  - task: lint_typescript_tests
    status: na
  - task: lint_license_headers
    status: passed
---

Author: Planeshifter

lib/node_modules/@stdlib/_tools/eslint/rules/require-file-extensions/test/fixtures/valid.js

@@ -22,12 +22,6 @@
 
 var resolve = require( 'path' ).resolve;
 var join = require( 'path' ).join;
-var rootDir = require( '@stdlib/_tools/utils/root-dir' );
-
-
-// VARIABLES //
-
-var ROOT_DIR = rootDir();
 
 
 // MAIN //
@@ -117,9 +111,9 @@ test = {
 	'code': [
 		'// MODULES //',
 		'',
-		'var main = require( \'./main.js\' );'
+		'var invalid = require( \'./invalid.js\' );'
 	].join( '\n' ),
-	'filename': join( ROOT_DIR, 'lib/index.js' )
+	'filename': join( __dirname, 'valid.js' ) // need to be able to resolve relative paths
 };
 valid.push( test );