diff --git a/site/src/utils/tar.jest.ts b/site/src/utils/tar.test.ts
similarity index 100%
rename from site/src/utils/tar.jest.ts
rename to site/src/utils/tar.test.ts
diff --git a/site/test/vitestSetup.ts b/site/test/vitestSetup.ts
new file mode 100644
index 0000000000..7a166c5a86
--- /dev/null
+++ b/site/test/vitestSetup.ts
@@ -0,0 +1,10 @@
+import { Blob as NativeBlob } from "node:buffer";
+
+// JSDom `Blob` is missing important methods[1] that have been standardized for
+// years. MDN categorizes this API as baseline[2].
+// [1]: https://github.com/jsdom/jsdom/issues/2555
+// [2]: https://developer.mozilla.org/en-US/docs/Web/API/Blob/arrayBuffer
+// @ts-expect-error - Minor type incompatibilities due to TypeScript's
+// introduction of the `ArrayBufferLife` type and the related generic parameters
+// changes.
+globalThis.Blob = NativeBlob;
diff --git a/site/vite.config.mts b/site/vite.config.mts
index fd656a11de..4319a560f4 100644
--- a/site/vite.config.mts
+++ b/site/vite.config.mts
@@ -137,7 +137,7 @@ export default defineConfig({
 		include: ["src/**/*.test.?(m)ts?(x)"],
 		globals: true,
 		environment: "jsdom",
-		setupFiles: ["@testing-library/jest-dom/vitest"],
+		setupFiles: ["@testing-library/jest-dom/vitest", "./test/vitestSetup.ts"],
 		silent: "passed-only",
 	},
 });