Prevent the no-import-test rule to crash when imported path is not a string (#228)

Author: GMartigny

rules/no-import-test-files.js

@@ -28,6 +28,10 @@ function getProjectInfo() {
 
 function createImportValidator(context, files, projectInfo, filename) {
 	return (node, importPath) => {
+		if (!importPath || typeof importPath !== 'string') {
+			return;
+		}
+
 		const isImportingExternalModule = isExternalModule(importPath);
 		if (isImportingExternalModule) {
 			return;
@@ -70,7 +74,7 @@ const create = context => {
 				return;
 			}
 
-			if (node.arguments[0] && node.arguments[0].type === 'Literal') {
+			if (node.arguments[0]) {
 				validateImportPath(node, node.arguments[0].value);
 			}
 		}

test/no-import-test-files.js

@@ -33,7 +33,9 @@ ruleTester.run('no-import-test-files', rule, {
 		{
 			code: 'var highlight = require(\'highlight.js\')',
 			filename: toPath('test/index.js')
-		}
+		},
+		'const value = require(true);',
+		'const value = require();'
 	],
 	invalid: [
 		{