diff --git a/test/benchmark-render-dashboard-script.test.ts b/test/benchmark-render-dashboard-script.test.ts
new file mode 100644
index 00000000..19e1412a
--- /dev/null
+++ b/test/benchmark-render-dashboard-script.test.ts
@@ -0,0 +1,204 @@
+import { spawnSync } from "node:child_process";
+import { rm } from "node:fs/promises";
+import { mkdtempSync, mkdirSync, readFileSync, writeFileSync } from "node:fs";
+import { tmpdir } from "node:os";
+import path from "node:path";
+import { afterEach, describe, expect, it } from "vitest";
+
+const scriptPath = path.resolve(
+	process.cwd(),
+	"scripts",
+	"benchmark-render-dashboard.mjs",
+);
+const tempRoots: string[] = [];
+
+async function removeWithRetry(
+	targetPath: string,
+	options: { recursive?: boolean; force?: boolean },
+): Promise<void> {
+	const retryableCodes = new Set(["ENOTEMPTY", "EPERM", "EBUSY"]);
+	const maxAttempts = 6;
+
+	for (let attempt = 1; attempt <= maxAttempts; attempt += 1) {
+		try {
+			await rm(targetPath, options);
+			return;
+		} catch (error) {
+			const code =
+				error &&
+				typeof error === "object" &&
+				"code" in error &&
+				typeof error.code === "string"
+					? error.code
+					: undefined;
+			if (!code || !retryableCodes.has(code) || attempt === maxAttempts) {
+				throw error;
+			}
+			await new Promise((resolve) => setTimeout(resolve, attempt * 50));
+		}
+	}
+}
+
+function createSummaryFixture() {
+	return {
+		meta: {
+			generatedAt: "2026-03-22T00:00:00.000Z",
+			preset: "codex-core",
+			models: ["gpt-5-codex"],
+			tasks: ["task-1"],
+			modes: ["patch", "replace", "hashline", "hashline_v2"],
+			runCount: 1,
+			warmupCount: 0,
+		},
+		rows: [
+			{
+				modelId: "gpt-5-codex",
+				displayName: "GPT-5 Codex",
+				modes: {
+					patch: {
+						accuracyPct: 90,
+						wallMsP50: 1000,
+						tokensTotalP50: 100,
+					},
+					replace: {
+						accuracyPct: 85,
+						wallMsP50: 1100,
+						tokensTotalP50: 90,
+					},
+					hashline: {
+						accuracyPct: 88,
+						wallMsP50: 1050,
+						tokensTotalP50: 95,
+					},
+					hashline_v2: {
+						accuracyPct: 92,
+						wallMsP50: 980,
+						tokensTotalP50: 80,
+					},
+				},
+			},
+		],
+		failures: [],
+	};
+}
+
+function createTempRoot(suffix = ""): string {
+	const root = mkdtempSync(path.join(tmpdir(), `bench-render${suffix}-`));
+	tempRoots.push(root);
+	return root;
+}
+
+function writeSummary(inputPath: string): void {
+	writeFileSync(inputPath, JSON.stringify(createSummaryFixture(), null, 2), "utf8");
+}
+
+function runRenderDashboard(args: string[]) {
+	return spawnSync(process.execPath, [scriptPath, ...args], {
+		encoding: "utf8",
+		timeout: 10_000,
+	});
+}
+
+afterEach(async () => {
+	while (tempRoots.length > 0) {
+		const root = tempRoots.pop();
+		if (root) {
+			await removeWithRetry(root, { recursive: true, force: true });
+		}
+	}
+});
+
+describe("benchmark render dashboard script", () => {
+	it("renders HTML from a minimal summary file", () => {
+		const root = createTempRoot();
+		const inputPath = path.join(root, "summary.json");
+		const outputPath = path.join(root, "dashboard.html");
+
+		writeSummary(inputPath);
+
+		const result = runRenderDashboard([
+			`--input=${inputPath}`,
+			`--output=${outputPath}`,
+		]);
+
+		expect(result.error).toBeUndefined();
+		expect(result.status).toBe(0);
+		expect(result.stderr).toBe("");
+		expect(result.stdout).toContain("Dashboard written:");
+		const html = readFileSync(outputPath, "utf8");
+		expect(html).toContain("Code Edit Format Benchmark");
+		expect(html).toContain("GPT-5 Codex");
+	});
+
+	it("renders HTML when input and output paths contain spaces", () => {
+		const root = createTempRoot(" spaces");
+		const spacedDir = path.join(root, "with spaces");
+		mkdirSync(spacedDir, { recursive: true });
+		const inputPath = path.join(spacedDir, "summary file.json");
+		const outputPath = path.join(spacedDir, "dashboard output.html");
+
+		writeSummary(inputPath);
+
+		const result = runRenderDashboard([
+			`--input=${inputPath}`,
+			`--output=${outputPath}`,
+		]);
+
+		expect(result.error).toBeUndefined();
+		expect(result.status).toBe(0);
+		expect(result.stderr).toBe("");
+		expect(result.stdout).toContain("Dashboard written:");
+		expect(readFileSync(outputPath, "utf8")).toContain("GPT-5 Codex");
+	});
+
+	it("fails with stderr when the input file is missing", () => {
+		const root = createTempRoot();
+		const inputPath = path.join(root, "missing-summary.json");
+		const outputPath = path.join(root, "dashboard.html");
+
+		const result = runRenderDashboard([
+			`--input=${inputPath}`,
+			`--output=${outputPath}`,
+		]);
+
+		expect(result.status).toBe(1);
+		expect(result.stderr).toContain("Render failed:");
+		expect(result.stderr.toLowerCase()).toContain("no such file");
+		expect(result.stdout).not.toContain("Dashboard written:");
+	});
+
+	it("fails with stderr when the summary json is malformed", () => {
+		const root = createTempRoot();
+		const inputPath = path.join(root, "summary.json");
+		const outputPath = path.join(root, "dashboard.html");
+
+		writeFileSync(inputPath, "{ not-valid-json", "utf8");
+
+		const result = runRenderDashboard([
+			`--input=${inputPath}`,
+			`--output=${outputPath}`,
+		]);
+
+		expect(result.status).toBe(1);
+		expect(result.stderr).toContain("Render failed:");
+		expect(result.stderr.toLowerCase()).toContain("json");
+		expect(result.stdout).not.toContain("Dashboard written:");
+	});
+
+	it("fails with stderr when the output directory does not exist", () => {
+		const root = createTempRoot();
+		const inputPath = path.join(root, "summary.json");
+		const outputPath = path.join(root, "missing", "dashboard.html");
+
+		writeSummary(inputPath);
+
+		const result = runRenderDashboard([
+			`--input=${inputPath}`,
+			`--output=${outputPath}`,
+		]);
+
+		expect(result.status).toBe(1);
+		expect(result.stderr).toContain("Render failed:");
+		expect(result.stdout).not.toContain("Dashboard written:");
+	});
+});