fix(test): Use join for FileTree path

bids-validator/src/files/browser.test.ts

@@ -1,5 +1,6 @@
 import { FileIgnoreRules } from './ignore.ts'
 import { FileTree } from '../types/filetree.ts'
+import { join } from '../deps/path.ts'
 import { assertEquals, assertObjectMatch } from '../deps/asserts.ts'
 import { BIDSFileBrowser, fileListToTree } from './browser.ts'
 
@@ -59,7 +60,7 @@ Deno.test('Browser implementation of FileTree', async (t) => {
     const tree = await fileListToTree(files)
     const expectedTree = new FileTree('', '/', undefined)
     const sub01Tree = new FileTree('sub-01', 'sub-01', expectedTree)
-    const anatTree = new FileTree('sub-01/anat', 'anat', sub01Tree)
+    const anatTree = new FileTree(join('sub-01', 'anat'), 'anat', sub01Tree)
     expectedTree.files = files
       .slice(0, 3)
       .map((f) => new BIDSFileBrowser(f, ignore))
@@ -86,4 +87,4 @@ Deno.test("Spread copies of BIDSFileBrowser contain name and path properties", a
   assertEquals(tree, expectedTree)
   const spreadFile = {...expectedTree.files[0], evidence: "test evidence"}
   assertObjectMatch(spreadFile, {name: "dataset_description.json", path: "/dataset_description.json", evidence: "test evidence"})
-})
+})