fix: Fix resolving of k6 executable (no-changelog) (#10511)

Co-authored-by: Iván Ovejero <ivov.src@gmail.com>

packages/@n8n/benchmark/src/testExecution/k6Executor.ts

@@ -1,4 +1,4 @@
-import { $ } from 'zx';
+import { $, which } from 'zx';
 import { Scenario } from '@/types/scenario';
 
 /**
@@ -14,15 +14,31 @@ export class K6Executor {
 		// For 1 min with 5 virtual users
 		const stage = '1m:5';
 
+		const k6ExecutablePath = await this.resolveK6ExecutablePath();
+
 		const processPromise = $({
 			cwd: scenario.scenarioDirPath,
 			env: {
 				API_BASE_URL: this.n8nApiBaseUrl,
 			},
-		})`${this.k6ExecutablePath} run --quiet --stage ${stage} ${scenario.scriptPath}`;
+		})`${k6ExecutablePath} run --quiet --stage ${stage} ${scenario.scriptPath}`;
 
 		for await (const chunk of processPromise.stdout) {
 			console.log(chunk.toString());
 		}
 	}
+
+	/**
+	 * @returns Resolved path to the k6 executable
+	 */
+	private async resolveK6ExecutablePath(): Promise<string> {
+		const k6ExecutablePath = await which(this.k6ExecutablePath, { nothrow: true });
+		if (!k6ExecutablePath) {
+			throw new Error(
+				'Could not find k6 executable based on your `PATH`. Please ensure k6 is available in your system and add it to your `PATH` or specify the path to the k6 executable using the `K6_PATH` environment variable.',
+			);
+		}
+
+		return k6ExecutablePath;
+	}
 }