wpt: add FormData wpts

lib/fetch/formdata.js

@@ -11,11 +11,11 @@ class FormData {
   static name = 'FormData'
 
   constructor (form) {
-    if (arguments.length > 0 && form != null) {
+    if (form !== undefined) {
       webidl.errors.conversionFailed({
         prefix: 'FormData constructor',
         argument: 'Argument 1',
-        types: ['null']
+        types: ['undefined']
       })
     }
 
@@ -297,9 +297,15 @@ function makeEntry (name, value, filename) {
     // 2. If filename is given, then set value to a new File object,
     //    representing the same bytes, whose name attribute is filename.
     if (filename !== undefined) {
+      /** @type {FilePropertyBag} */
+      const options = {
+        type: value.type,
+        lastModified: value.lastModified
+      }
+
       value = value instanceof File
-        ? new File([value], filename, { type: value.type })
-        : new FileLike(value, filename, { type: value.type })
+        ? new File([value], filename, options)
+        : new FileLike(value, filename, options)
     }
   }
 

package.json

@@ -53,7 +53,7 @@
     "test:tap": "tap test/*.js test/diagnostics-channel/*.js",
     "test:tdd": "tap test/*.js test/diagnostics-channel/*.js -w",
     "test:typescript": "tsd",
-    "test:wpt": "node scripts/verifyVersion 18 || (node test/wpt/start-fetch.mjs && node test/wpt/start-FileAPI.mjs && node test/wpt/start-mimesniff.mjs)",
+    "test:wpt": "node scripts/verifyVersion 18 || (node test/wpt/start-fetch.mjs && node test/wpt/start-FileAPI.mjs && node test/wpt/start-mimesniff.mjs && node test/wpt/start-xhr.mjs)",
     "coverage": "nyc --reporter=text --reporter=html npm run test",
     "coverage:ci": "nyc --reporter=lcov npm run test",
     "bench": "PORT=3042 concurrently -k -s first npm:bench:server npm:bench:run",