From 56f330a34415156ef7644d5290cc81fd52485607 Mon Sep 17 00:00:00 2001
From: Danny Canter <danny_canter@apple.com>
Date: Fri, 7 Nov 2025 02:05:06 -0800
Subject: [PATCH] Integration: Add stdio ingest test

Add a test to ingest 500MiB of data across stdout/stderr. Useful to test
how fast we can ingest stdio. The timing will always be a tad off as it
times between start and wait returning, and there's quite a lot in the way..
but it's a good enough metric.
---
 Sources/Integration/ContainerTests.swift | 75 ++++++++++++++++++++++++
 Sources/Integration/Suite.swift          |  1 +
 2 files changed, 76 insertions(+)

diff --git a/Sources/Integration/ContainerTests.swift b/Sources/Integration/ContainerTests.swift
index 36cd447b..89cb96a2 100644
--- a/Sources/Integration/ContainerTests.swift
+++ b/Sources/Integration/ContainerTests.swift
@@ -64,6 +64,18 @@ extension IntegrationSuite {
         }
     }
 
+    final class DiscardingWriter: @unchecked Sendable, Writer {
+        var count: Int = 0
+
+        func write(_ data: Data) throws {
+            count += data.count
+        }
+
+        func close() throws {
+            return
+        }
+    }
+
     final class BufferWriter: Writer {
         // `data` isn't used concurrently.
         nonisolated(unsafe) var data = Data()
@@ -1027,4 +1039,67 @@ extension IntegrationSuite {
         try "hello".write(to: dir.appendingPathComponent("hi.txt"), atomically: true, encoding: .utf8)
         return dir
     }
+
+    func testLargeStdioOutput() async throws {
+        let id = "test-large-stdout-stderr-output"
+
+        let bs = try await bootstrap(id)
+        let container = try LinuxContainer(id, rootfs: bs.rootfs, vmm: bs.vmm) { config in
+            config.process.arguments = ["/bin/sleep", "1000"]
+            config.bootlog = bs.bootlog
+        }
+
+        do {
+            try await container.create()
+            try await container.start()
+
+            let stdoutBuffer = DiscardingWriter()
+            let stderrBuffer = DiscardingWriter()
+
+            let exec = try await container.exec("large-output") { config in
+                config.arguments = [
+                    "sh",
+                    "-c",
+                    """
+                    dd if=/dev/zero bs=1M count=250 status=none && \
+                    dd if=/dev/zero bs=1M count=250 status=none >&2
+                    """,
+                ]
+                config.stdout = stdoutBuffer
+                config.stderr = stderrBuffer
+            }
+
+            let started = CFAbsoluteTimeGetCurrent()
+
+            try await exec.start()
+            let status = try await exec.wait()
+
+            let lasted = CFAbsoluteTimeGetCurrent() - started
+            print("Test \(id) finished process ingesting stdio in \(lasted)")
+
+            guard status.exitCode == 0 else {
+                throw IntegrationError.assert(msg: "exec process status \(status) != 0")
+            }
+
+            try await exec.delete()
+
+            let expectedSize = 250 * 1024 * 1024
+            guard stdoutBuffer.count == expectedSize else {
+                throw IntegrationError.assert(
+                    msg: "stdout size \(stdoutBuffer.count) != expected \(expectedSize)")
+            }
+
+            guard stderrBuffer.count == expectedSize else {
+                throw IntegrationError.assert(
+                    msg: "stderr size \(stderrBuffer.count) != expected \(expectedSize)")
+            }
+
+            try await container.kill(SIGKILL)
+            try await container.wait()
+            try await container.stop()
+        } catch {
+            try? await container.stop()
+            throw error
+        }
+    }
 }
diff --git a/Sources/Integration/Suite.swift b/Sources/Integration/Suite.swift
index 23d22a8d..7dc6624a 100644
--- a/Sources/Integration/Suite.swift
+++ b/Sources/Integration/Suite.swift
@@ -295,6 +295,7 @@ struct IntegrationSuite: AsyncParsableCommand {
             Test("container no serial console", testNoSerialConsole),
             Test("unix socket into guest", testUnixSocketIntoGuest),
             Test("container non-closure constructor", testNonClosureConstructor),
+            Test("container test large stdio ingest", testLargeStdioOutput),
 
             // Pods
             Test("pod single container", testPodSingleContainer),