Fix failing unit tests on Node 14 and 16

Author: rubensworks

package.json

@@ -73,7 +73,8 @@
     "typescript": "^5.0.0",
     "readable-stream-node-to-web": "^1.0.1",
     "webpack": "^5.73.0",
-    "webpack-cli": "^4.10.0"
+    "webpack-cli": "^4.10.0",
+    "web-streams-ponyfill": "^1.4.2"
   },
   "jest": {
     "transform": {

test/SparqlEndpointFetcher-test.ts

@@ -9,6 +9,10 @@ const DF = new DataFactory();
 
 // tslint:disable:no-trailing-whitespace
 
+if (!globalThis.ReadableStream) {
+  globalThis.ReadableStream = require('web-streams-ponyfill').ReadableStream;
+}
+
 describe('SparqlEndpointFetcher', () => {
 
   describe('constructed without fetch callback', () => {

yarn.lock

@@ -3880,6 +3880,11 @@ watchpack@^2.3.1:
     glob-to-regexp "^0.4.1"
     graceful-fs "^4.1.2"
 
+web-streams-ponyfill@^1.4.2:
+  version "1.4.2"
+  resolved "https://registry.yarnpkg.com/web-streams-ponyfill/-/web-streams-ponyfill-1.4.2.tgz#0ae863cc5f7493903679f16b08cbf14d432b62f4"
+  integrity sha512-LCHW+fE2UBJ2vjhqJujqmoxh1ytEDEr0dPO3CabMdMDJPKmsaxzS90V1Ar6LtNE5VHLqxR4YMEj1i4lzMAccIA==
+
 webidl-conversions@^3.0.0:
   version "3.0.1"
   resolved "https://registry.yarnpkg.com/webidl-conversions/-/webidl-conversions-3.0.1.tgz#24534275e2a7bc6be7bc86611cc16ae0a5654871"