diff --git a/src/docker-build-cache.test.ts b/src/docker-build-cache.test.ts
index 434751341d2..65b59ab0342 100644
--- a/src/docker-build-cache.test.ts
+++ b/src/docker-build-cache.test.ts
@@ -1,12 +1,39 @@
 import { readFile } from "node:fs/promises";
 import { resolve } from "node:path";
 import { fileURLToPath } from "node:url";
-import { describe, expect, it } from "vitest";
+import { beforeAll, describe, expect, it } from "vitest";
 
 const repoRoot = resolve(fileURLToPath(new URL(".", import.meta.url)), "..");
+const dockerfilePaths = [
+  "Dockerfile",
+  "Dockerfile.sandbox",
+  "Dockerfile.sandbox-browser",
+  "Dockerfile.sandbox-common",
+  "scripts/docker/cleanup-smoke/Dockerfile",
+  "scripts/docker/install-sh-smoke/Dockerfile",
+  "scripts/docker/install-sh-e2e/Dockerfile",
+  "scripts/docker/install-sh-nonroot/Dockerfile",
+  "scripts/e2e/Dockerfile",
+  "scripts/e2e/Dockerfile.qr-import",
+] as const;
+const aptCacheDockerfilePaths = dockerfilePaths.filter(
+  (path) => path !== "scripts/e2e/Dockerfile.qr-import" && path !== "scripts/e2e/Dockerfile",
+);
+const shellContinuationDockerfilePaths = dockerfilePaths.filter(
+  (path) =>
+    path !== "Dockerfile" &&
+    path !== "scripts/e2e/Dockerfile" &&
+    path !== "scripts/e2e/Dockerfile.qr-import",
+);
+const repoFileCache = new Map<string, Promise<string>>();
 
 async function readRepoFile(path: string): Promise<string> {
-  return readFile(resolve(repoRoot, path), "utf8");
+  let cached = repoFileCache.get(path);
+  if (!cached) {
+    cached = readFile(resolve(repoRoot, path), "utf8");
+    repoFileCache.set(path, cached);
+  }
+  return cached;
 }
 
 function indexOfPattern(source: string, pattern: RegExp): number {
@@ -14,6 +41,10 @@ function indexOfPattern(source: string, pattern: RegExp): number {
 }
 
 describe("docker build cache layout", () => {
+  beforeAll(async () => {
+    await Promise.all(dockerfilePaths.map((path) => readRepoFile(path)));
+  });
+
   it("keeps the root dependency layer independent from scripts changes", async () => {
     const dockerfile = await readRepoFile("Dockerfile");
     const installIndex = dockerfile.indexOf("pnpm install --frozen-lockfile");
@@ -42,16 +73,7 @@ describe("docker build cache layout", () => {
   });
 
   it("uses apt cache mounts in Dockerfiles that install system packages", async () => {
-    for (const path of [
-      "Dockerfile",
-      "Dockerfile.sandbox",
-      "Dockerfile.sandbox-browser",
-      "Dockerfile.sandbox-common",
-      "scripts/docker/cleanup-smoke/Dockerfile",
-      "scripts/docker/install-sh-smoke/Dockerfile",
-      "scripts/docker/install-sh-e2e/Dockerfile",
-      "scripts/docker/install-sh-nonroot/Dockerfile",
-    ]) {
+    for (const path of aptCacheDockerfilePaths) {
       const dockerfile = await readRepoFile(path);
       expect(dockerfile, `${path} should cache apt package archives`).toContain(
         "target=/var/cache/apt,sharing=locked",
@@ -71,15 +93,7 @@ describe("docker build cache layout", () => {
   });
 
   it("does not leave blank lines after shell continuation markers", async () => {
-    for (const path of [
-      "Dockerfile.sandbox",
-      "Dockerfile.sandbox-browser",
-      "Dockerfile.sandbox-common",
-      "scripts/docker/cleanup-smoke/Dockerfile",
-      "scripts/docker/install-sh-smoke/Dockerfile",
-      "scripts/docker/install-sh-e2e/Dockerfile",
-      "scripts/docker/install-sh-nonroot/Dockerfile",
-    ]) {
+    for (const path of shellContinuationDockerfilePaths) {
       const dockerfile = await readRepoFile(path);
       expect(
         dockerfile,