feat: add getScriptPubKeyLength function in test

Issue: BTC-1451

Author: OttoAllmendinger

packages/wasm-miniscript/test/test.ts

@@ -17,6 +17,25 @@ function removeChecksum(descriptor: string): string {
   return parts[0];
 }
 
+function getScriptPubKeyLength(descType: string): number {
+  switch (descType) {
+    case "Wpkh":
+      return 22;
+    case "Sh":
+    case "ShWsh":
+    case "ShWpkh":
+      return 23;
+    case "Pkh":
+      return 25;
+    case "Wsh":
+      return 34;
+    case "Bare":
+      throw new Error("cannot determine scriptPubKey length for Bare descriptor");
+    default:
+      throw new Error("unexpected descriptor type " + descType);
+  }
+}
+
 describe("Descriptor fixtures", function () {
   fixtures.valid.forEach((fixture, i) => {
     it("should parse fixture " + i, function () {
@@ -51,12 +70,17 @@ describe("Descriptor fixtures", function () {
           descriptorString = removeChecksum(descriptorString);
         }
         const descriptor = Descriptor.fromString(descriptorString, "derivable");
-        assert.strictEqual(
-          Buffer.from(descriptor.atDerivationIndex(fixture.index ?? 0).scriptPubkey()).toString(
-            "hex",
-          ),
-          fixture.script,
+        const scriptPubKey = Buffer.from(
+          descriptor.atDerivationIndex(fixture.index ?? 0).scriptPubkey(),
         );
+        assert.strictEqual(scriptPubKey.toString("hex"), fixture.script);
+        if (descriptor.descType() !== "Bare") {
+          assert.strictEqual(
+            scriptPubKey.length,
+            getScriptPubKeyLength(descriptor.descType()),
+            `Unexpected scriptPubKey length for descriptor ${descriptor.descType()}: ${scriptPubKey.length}`,
+          );
+        }
       }
 
       assert.ok(Number.isInteger(descriptor.maxWeightToSatisfy()));