Custom message for assertions about files existing in packs

Author: Dave Bartolomeo

extensions/ql-vscode/test/vscode-tests/cli-integration/variant-analysis/variant-analysis-manager.test.ts

@@ -20,10 +20,47 @@ import { ExtensionApp } from "../../../../src/common/vscode/vscode-app";
 import { DbConfigStore } from "../../../../src/databases/config/db-config-store";
 import { mockedQuickPickItem } from "../../utils/mocking.helpers";
 import { QueryLanguage } from "../../../../src/common/query-language";
+import type { QueryPackFS } from "../../utils/bundled-pack-helpers";
 import { readBundledPack } from "../../utils/bundled-pack-helpers";
 import { load } from "js-yaml";
 import type { ExtensionPackMetadata } from "../../../../src/model-editor/extension-pack-metadata";
 import type { QlPackLockFile } from "../../../../src/packaging/qlpack-lock-file";
+import { expect } from "@jest/globals";
+import type { ExpectationResult } from "expect";
+
+/**
+ * Custom Jest matcher to check if a file exists in a query pack.
+ */
+function toExistInPack(
+  this: jest.MatcherContext,
+  actual: unknown,
+  packFS: QueryPackFS,
+): ExpectationResult {
+  if (typeof actual !== "string") {
+    throw new TypeError("Expected actual value to be a string.");
+  }
+
+  const pass = packFS.fileExists(actual);
+  if (pass) {
+    return {
+      pass: true,
+      message: () => `expected ${actual} not to exist in pack`,
+    };
+  } else {
+    return {
+      pass: false,
+      message: () => `expected ${actual} to exist in pack`,
+    };
+  }
+}
+
+expect.extend({ toExistInPack });
+
+declare module "expect" {
+  interface Matchers<R> {
+    toExistInPack(packFS: QueryPackFS): R;
+  }
+}
 
 describe("Variant Analysis Manager", () => {
   let cli: CodeQLCliServer;
@@ -331,14 +368,14 @@ describe("Variant Analysis Manager", () => {
 
       const packFS = await readBundledPack(request.query.pack);
       filesThatExist.forEach((file) => {
-        expect(packFS.fileExists(file)).toBe(true);
+        expect(file).toExistInPack(packFS);
       });
 
       qlxFilesThatExist.forEach((file) => {
-        expect(packFS.fileExists(file)).toBe(true);
+        expect(file).toExistInPack(packFS);
       });
       filesThatDoNotExist.forEach((file) => {
-        expect(packFS.fileExists(file)).toBe(false);
+        expect(file).not.toExistInPack(packFS);
       });
 
       expect(

extensions/ql-vscode/test/vscode-tests/utils/bundled-pack-helpers.ts

@@ -4,7 +4,7 @@ import { extract as tar_extract } from "tar-stream";
 import { pipeline } from "stream/promises";
 import { createGunzip } from "zlib";
 
-interface QueryPackFS {
+export interface QueryPackFS {
   fileExists: (name: string) => boolean;
   fileContents: (name: string) => Buffer;
   directoryContents: (name: string) => string[];