Add tests to detect changes native fetch error behavior

packages/utils/test/unit/fetch.test.ts

@@ -0,0 +1,112 @@
+import "../setup.js";
+import crypto from "node:crypto";
+import http from "node:http";
+import {expect} from "chai";
+import {FetchError, FetchErrorType, fetch} from "../../src/fetch.js";
+
+describe("FetchError", function () {
+  const port = 37421;
+  const randomHex = crypto.randomBytes(32).toString("hex");
+
+  const testCases: {
+    id: string;
+    url?: string;
+    requestListener?: http.RequestListener;
+    abort?: true;
+    timeout?: number;
+    errorType: FetchErrorType;
+    errorCode: string;
+    expectCause: boolean;
+  }[] = [
+    {
+      id: "Bad domain",
+      // Use random bytes to ensure no collisions
+      url: `https://${randomHex}.infura.io`,
+      errorType: "failed",
+      errorCode: "ENOTFOUND",
+      expectCause: true,
+    },
+    {
+      id: "Bad port",
+      url: `http://localhost:${port + 1}`,
+      requestListener: (_req, res) => res.end(),
+      errorType: "failed",
+      errorCode: "ECONNREFUSED",
+      expectCause: true,
+    },
+    {
+      id: "Socket error",
+      requestListener: (_req, res) => res.socket?.destroy(),
+      errorType: "failed",
+      errorCode: "UND_ERR_SOCKET",
+      expectCause: true,
+    },
+    {
+      id: "Unknown scheme",
+      url: `httsp://localhost:${port}`,
+      errorType: "failed",
+      errorCode: "ERR_FETCH_FAILED",
+      expectCause: true,
+    },
+    {
+      id: "Invalid URL",
+      url: "invalid-url",
+      errorType: "input",
+      errorCode: "ERR_INVALID_URL",
+      expectCause: true,
+    },
+    {
+      id: "Aborted request",
+      abort: true,
+      requestListener: () => {
+        // leave the request open until aborted
+      },
+      errorType: "aborted",
+      errorCode: "ERR_ABORTED",
+      expectCause: false,
+    },
+  ];
+
+  const afterHooks: (() => Promise<void>)[] = [];
+
+  afterEach(async function () {
+    while (afterHooks.length) {
+      const afterHook = afterHooks.pop();
+      if (afterHook)
+        await afterHook().catch((e: Error) => {
+          // eslint-disable-next-line no-console
+          console.error("Error in afterEach hook", e);
+        });
+    }
+  });
+
+  for (const testCase of testCases) {
+    const {id, url = `http://localhost:${port}`, requestListener, abort} = testCase;
+
+    it(id, async function () {
+      if (requestListener) {
+        const server = http.createServer(requestListener);
+        await new Promise<void>((resolve) => server.listen(port, resolve));
+        afterHooks.push(
+          () =>
+            new Promise((resolve, reject) =>
+              server.close((err) => {
+                if (err) reject(err);
+                else resolve();
+              })
+            )
+        );
+      }
+
+      const controller = new AbortController();
+      if (abort) setTimeout(() => controller.abort(), 20);
+      await expect(fetch(url, {signal: controller.signal})).to.be.rejected.then((error: FetchError) => {
+        expect(error.type).to.be.equal(testCase.errorType);
+        expect(error.code).to.be.equal(testCase.errorCode);
+        if (testCase.expectCause) {
+          expect(error.cause).to.be.instanceof(Error);
+        }
+      });
+    });
+  }
+});