fix: add missing async test fixes

internal/linker/link_node_modules.ts

@@ -31,7 +31,7 @@ async function symlink(target: string, path: string) {
   try{
     await fs.promises.symlink(target, path, 'junction');
   } catch(e){
-    if(e.code !== 'ENOENT'){
+    if(e.code !== 'EEXIST'){
       throw e;
     }
     // We assume here that the path is already linked to the correct target.

internal/linker/test/link_node_modules.spec.ts

@@ -31,25 +31,25 @@ describe('link_node_modules', () => {
     mkdirp(workspace);
   });
 
-  it('should report when modules manifest absent', () => {
+  it('should report when modules manifest absent',async () => {
     try {
-      (linker as any).main();
+      await (linker as any).main();
     } catch (expected) {
       expect(expected.message).toContain('requires one argument');
     }
     try {
-      (linker as any).main([]);
+      await (linker as any).main([]);
     } catch (expected) {
       expect(expected.message).toContain('requires one argument');
     }
     try {
-      (linker as any).main(['bad_path']);
+      await (linker as any).main(['bad_path']);
     } catch (expected) {
       expect(expected.message).toContain('ENOENT');
     }
   });
 
-  it('should handle first-party packages in workspace', () => {
+  it('should handle first-party packages in workspace', async() => {
     // Set the cwd() like Bazel would in the execroot
     process.chdir(workspace);
 
@@ -62,15 +62,15 @@ describe('link_node_modules', () => {
       'workspace': workspace,
     });
 
-    linker.main(['manifest.json'], {dir: process.env['RUNFILES_DIR']} as any);
+    await linker.main(['manifest.json'], {dir: process.env['RUNFILES_DIR']} as any);
 
     // The linker expects to run as its own process, so it changes the wd
     process.chdir(path.join());
     expect(fs.readdirSync(path.join(process.env['TEST_TMPDIR']!, workspace, 'node_modules', 'a')))
         .toContain('index.js');
   });
 
-  it('should handle third-party packages in runfiles', () => {
+  it('should handle third-party packages in runfiles', async () => {
     mkdirp('npm/node_modules/some-package');
     const idx = 'npm/node_modules/some-package/index.js';
     fs.writeFileSync(idx, 'exports = {}', 'utf-8');
@@ -82,7 +82,7 @@ describe('link_node_modules', () => {
     writeManifest({'root': 'npm/node_modules'});
     writeRunfiles(runfilesManifest);
 
-    linker.main(['manifest.json'], new linker.Runfiles());
+    await linker.main(['manifest.json'], new linker.Runfiles());
 
     // The linker expects to run as its own process, so it changes the wd
     process.chdir(path.join(process.env['TEST_TMPDIR']!, workspace));