integration-tests: use HttpWaitStrategy

Use URL's .path property instead of .path() method when removing stale
control sockets in ControlSocket.run(). The .path() method returns only
the relative component ('control.sock') while .path resolves to the
full absolute path. Since the cwd change happens after the cleanup,
removeItem silently failed to find the socket.

Add unit tests verifying controlSocketURL resolves correctly for both
absolute cleanup and relative binding use cases.

Fixes: https://github.com/cirruslabs/tart/issues/1220

Sources/tart/ControlSocket.swift

@@ -19,7 +19,7 @@ class ControlSocket {
   func run() async throws {
     // Remove control socket file from previous "tart run" invocations,
     // if any, otherwise we may get the "address already in use" error
-    try? FileManager.default.removeItem(atPath: controlSocketURL.path())
+    try? FileManager.default.removeItem(atPath: controlSocketURL.path)
 
     // Change the current working directory to a VM's base directory
     // to work around Unix domain socket 104 byte limitation [1]

Tests/TartTests/ControlSocketURLTests.swift

@@ -0,0 +1,28 @@
+import XCTest
+@testable import tart
+
+final class ControlSocketURLTests: XCTestCase {
+  func testControlSocketURLResolvesToAbsolutePath() throws {
+    let baseURL = URL(fileURLWithPath: "/Users/test/.tart/vms/myvm/")
+    let vmDir = VMDirectory(baseURL: baseURL)
+
+    // The .path property resolves relative URLs to absolute paths,
+    // which is required for stale socket cleanup in ControlSocket.run()
+    // since it happens before the working directory is changed.
+    XCTAssertEqual(
+      vmDir.controlSocketURL.path,
+      "/Users/test/.tart/vms/myvm/control.sock"
+    )
+  }
+
+  func testControlSocketURLRelativePathIsJustFilename() throws {
+    let baseURL = URL(fileURLWithPath: "/Users/test/.tart/vms/myvm/")
+    let vmDir = VMDirectory(baseURL: baseURL)
+
+    // The .relativePath is used for socket binding after cwd is changed
+    XCTAssertEqual(
+      vmDir.controlSocketURL.relativePath,
+      "control.sock"
+    )
+  }
+}

docs/faq.md

@@ -59,7 +59,7 @@ Remote images are pulled into `~/.tart/cache/OCIs/`.
 ## Nested virtualization support?
 
 Tart is limited by functionality of Apple's `Virtualization.Framework`. At the moment `Virtualization.Framework`
-supports nested virtualization only on M3 or M4 chips running macOS 15 (Sequoia) or later. By default, it is disabled, but can be enabled by passing the `--nested` flag to `tart run`.
+supports nested virtualization only on M3 or M4 chips running macOS 15 (Sequoia) or later and [only for Linux VMs](https://github.com/cirruslabs/tart/issues/1231#issuecomment-4410915463). By default, it is disabled, but can be enabled by passing the `--nested` flag to `tart run`.
 
 ## Connecting to a service running on host
 

integration-tests/docker_registry.py

@@ -1,7 +1,5 @@
-import requests
-
-from testcontainers.core.waiting_utils import wait_container_is_ready
 from testcontainers.core.container import DockerContainer
+from testcontainers.core.wait_strategies import HttpWaitStrategy
 
 
 class DockerRegistry(DockerContainer):
@@ -10,11 +8,9 @@ class DockerRegistry(DockerContainer):
     def __init__(self):
         super().__init__("registry:2")
         self.with_exposed_ports(self._default_exposed_port)
+        self.waiting_for(HttpWaitStrategy(self._default_exposed_port, "/v2/").for_status_code(200))
 
-    @wait_container_is_ready(requests.exceptions.ConnectionError)
     def remote_name(self, for_vm: str):
         exposed_port = self.get_exposed_port(self._default_exposed_port)
 
-        requests.get(f"http://127.0.0.1:{exposed_port}/v2/")
-
         return f"127.0.0.1:{exposed_port}/tart/{for_vm}:latest"

integration-tests/test_oci.py

@@ -46,7 +46,7 @@ def vm_with_random_disk(tart):
     disk_path = os.path.join(tart.home(), "vms", vm_name, "disk.img")
 
     with tempfile.NamedTemporaryFile(delete=False) as tf:
-        tf.write(os.urandom(amount_to_transfer.bytes))
+        tf.write(os.urandom(int(amount_to_transfer.bytes)))
         tf.close()
         os.rename(tf.name, disk_path)