Stub feature flag API endpoint in tests

src/testing-utils.ts

@@ -1,8 +1,11 @@
+import * as github from "@actions/github";
 import { TestInterface } from "ava";
 import * as sinon from "sinon";
 
+import * as apiClient from "./api-client";
 import * as CodeQL from "./codeql";
 import { Logger } from "./logging";
+import { HTTPError } from "./util";
 
 type TestContext = {
   stdoutWrite: any;
@@ -119,3 +122,30 @@ export function getRecordingLogger(messages: LoggedMessage[]): Logger {
     endGroup: () => undefined,
   };
 }
+
+/** Mock the HTTP request to the feature flags enablement API endpoint. */
+export function mockFeatureFlagApiEndpoint(
+  responseStatusCode: number,
+  response: { [flagName: string]: boolean }
+) {
+  // Passing an auth token is required, so we just use a dummy value
+  const client = github.getOctokit("123");
+
+  const requestSpy = sinon.stub(client, "request");
+
+  const optInSpy = requestSpy.withArgs(
+    "GET /repos/:owner/:repo/code-scanning/codeql-action/features"
+  );
+  if (responseStatusCode < 300) {
+    optInSpy.resolves({
+      status: responseStatusCode,
+      data: response,
+      headers: {},
+      url: "GET /repos/:owner/:repo/code-scanning/codeql-action/features",
+    });
+  } else {
+    optInSpy.throws(new HTTPError("some error message", responseStatusCode));
+  }
+
+  sinon.stub(apiClient, "getApiClient").value(() => client);
+}