test: use index.js if package.json "main" is empty

Verify that the module loader uses index.js when the "main" property of package.json is the empty string. Refs: #32013 PR-URL: #32040 Reviewed-By: Colin Ihrig <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Denys Otrishko <[email protected]> Reviewed-By: Richard Lau <[email protected]> Reviewed-By: Luigi Pinca <[email protected]>

Author: bnoordhuis

test/fixtures/require-empty-main/index.js

@@ -0,0 +1,2 @@
+'use strict';
+module.exports=42;

test/fixtures/require-empty-main/package.json

@@ -0,0 +1 @@
+{"main":""}

test/parallel/test-require-empty-main.js

@@ -0,0 +1,25 @@
+'use strict';
+require('../common');
+
+// A package.json with an empty "main" property should use index.js if present.
+// require.resolve() should resolve to index.js for the same reason.
+//
+// In fact, any "main" property that doesn't resolve to a file should result
+// in index.js being used, but that's already checked for by other tests.
+// This test only concerns itself with the empty string.
+
+constassert=require('assert');
+constpath=require('path');
+constfixtures=require('../common/fixtures');
+
+constwhere=fixtures.path('require-empty-main');
+constexpected=path.join(where,'index.js');
+
+test();
+setImmediate(test);
+
+functiontest(){
+assert.strictEqual(require.resolve(where),expected);
+assert.strictEqual(require(where),42);
+assert.strictEqual(require.resolve(where),expected);
+}