Fix empty label handling

index.js

@@ -130,7 +130,9 @@ function validateLabel(label, { checkHyphens, checkBidi, checkJoiners, processin
   }
 
   // https://tools.ietf.org/html/rfc5893#section-2
-  if (checkBidi) {
+  // For the codePoints length check, see discussion in https://github.com/jsdom/whatwg-url/pull/250 and the second item
+  // in https://github.com/whatwg/url/issues/744.
+  if (checkBidi && codePoints.length > 0) {
     let rtl;
 
     // 1

scripts/getLatestTests.js

@@ -14,6 +14,10 @@ const { unicodeVersion } = require("../package.json");
 
 const pipelinePromise = promisify(pipeline);
 
+// Update this by going to https://github.com/web-platform-tests/wpt/tree/master/url/resources and pressing "y" on the
+// keyboard.
+const wptSHA = "417a64d8351792b768efe089934edce3259f63d1";
+
 main().catch(e => {
   console.error(e);
   process.exit(1);
@@ -28,7 +32,12 @@ async function main() {
     })(),
     (async () => {
       const asciiTarget = fs.createWriteStream(path.resolve(__dirname, "../test/fixtures/toascii.json"));
-      const response = await fetch("https://github.com/web-platform-tests/wpt/raw/112ad5ca55d55f6da2ccc7468e6dcc91b4e5d223/url/resources/toascii.json");
+      const response = await fetch(`https://github.com/web-platform-tests/wpt/raw/${wptSHA}/url/resources/toascii.json`);
+      await pipelinePromise(response.body, asciiTarget);
+    })(),
+    (async () => {
+      const asciiTarget = fs.createWriteStream(path.resolve(__dirname, "../test/fixtures/IdnaTestV2ToASCII.json"));
+      const response = await fetch(`https://github.com/web-platform-tests/wpt/raw/${wptSHA}/url/resources/IdnaTestV2.json`);
       await pipelinePromise(response.body, asciiTarget);
     })()
   ]);

test/toascii.js

@@ -5,6 +5,7 @@ const assert = require("assert");
 const tr46 = require("../index.js");
 
 const toASCIITestCases = require("./fixtures/toascii.json");
+const idnaTestV2 = require("./fixtures/IdnaTestV2ToASCII.json");
 
 function testToASCII(testCase) {
   return () => {
@@ -29,7 +30,29 @@ describe("ToASCII", () => {
 
     let description = testCase.input;
     if (testCase.comment) {
-      description = ` (${testCase.comment})`;
+      description += ` (${testCase.comment})`;
+    }
+
+    specify(description, testToASCII(testCase));
+  }
+});
+
+describe("ToASCII via IdnaTestV2.json in wpt", () => {
+  for (const testCase of idnaTestV2) {
+    if (typeof testCase === "string") {
+      // It's a "comment"; skip it.
+      continue;
+    }
+
+    if (testCase.input.includes("?")) {
+      // ToASCII will not fail on these. But, the URL Standard will. IdnaTestV2.json is mostly focused on the URL
+      // Standard, so it expects failures. We should skip them.
+      continue;
+    }
+
+    let description = testCase.input;
+    if (testCase.comment) {
+      description += ` (${testCase.comment})`;
     }
 
     specify(description, testToASCII(testCase));