Refactor RestartTest to set up using 'eden start'

Summary:
RestartTest uses 'eden restart' during setup to start the fake_edenfs process. There are two issues with doing this:

* I want to extend the tests in RestartTest so they also tests with an ad-hoc fake_edenfs process (D10414995). Restarting edenfs during setup makes no sense in that context.
* I think using 'eden restart' during setup is clunky and unintuitive. 'eden start' is more appropriate.

Refactor RestartTest's setup so it uses 'eden start' instead. Also add a test which explicitly verifies that 'eden restart' starts fake_edenfs if no daemon is already running.

Reviewed By: chadaustin

Differential Revision: D10417304

fbshipit-source-id: 20f8190026cd153dd9b539067f6f63b6bd27abed

eden/integration/lib/fake_edenfs.py

@@ -20,13 +20,34 @@ from .find_executables import FindExe
 class FakeEdenFS(typing.ContextManager[int]):
     """A running fake_edenfs process."""
 
-    @staticmethod
+    @classmethod
     def spawn(
-        eden_dir: pathlib.Path, extra_arguments: typing.Sequence[str] = ()
+        cls, eden_dir: pathlib.Path, extra_arguments: typing.Sequence[str] = ()
     ) -> "FakeEdenFS":
         command = [FindExe.FAKE_EDENFS, "--edenDir", str(eden_dir)]
         command.extend(extra_arguments)
         subprocess.check_call(command)
+        return cls.from_existing_process(eden_dir=eden_dir)
+
+    @classmethod
+    def spawn_via_cli(
+        cls, eden_dir: pathlib.Path, extra_arguments: typing.Sequence[str] = ()
+    ) -> "FakeEdenFS":
+        command = [
+            FindExe.EDEN_CLI,
+            "--config-dir",
+            str(eden_dir),
+            "start",
+            "--daemon-binary",
+            FindExe.FAKE_EDENFS,
+            "--",
+        ]
+        command.extend(extra_arguments)
+        subprocess.check_call(command)
+        return cls.from_existing_process(eden_dir=eden_dir)
+
+    @staticmethod
+    def from_existing_process(eden_dir: pathlib.Path) -> "FakeEdenFS":
         edenfs_pid = int((eden_dir / "lock").read_text())
         return FakeEdenFS(process_id=edenfs_pid)
 

eden/integration/restart_test.py

@@ -8,16 +8,16 @@
 # of patent rights can be found in the PATENTS file in the same directory.
 
 import os
-import shutil
+import pathlib
 import subprocess
 import sys
 import unittest
-from typing import Any
 
 import eden.thrift
 import eden.thrift.client
 import pexpect
 
+from .lib.fake_edenfs import FakeEdenFS
 from .lib.find_executables import FindExe
 from .lib.temporary_directory import TemporaryDirectoryMixin
 
@@ -49,16 +49,21 @@ class RestartTest(unittest.TestCase, TemporaryDirectoryMixin):
         )
 
     def _start_fake_edenfs(self) -> int:
-        # Run "eden restart".  It should start it without prompting since edenfs is not
-        # already running.
+        daemon = FakeEdenFS.spawn_via_cli(eden_dir=pathlib.Path(self.tmp_dir))
+        return daemon.process_id
+
+    def test_restart_starts_edenfs_if_not_running(self) -> None:
+        """
+        Run "eden restart".  It should start it without prompting since edenfs
+        is not already running.
+        """
         p = self._spawn_restart()
         p.expect_exact("Eden is not currently running.  Starting it...")
         p.expect_exact("Starting fake edenfs daemon")
         p.expect(r"Started edenfs \(pid ([0-9]+)\)")
-        pid = int(p.match.group(1))
+        int(p.match.group(1))
         p.wait()
         self.assertEqual(p.exitstatus, 0)
-        return pid
 
     def _get_thrift_client(self) -> eden.thrift.EdenClient:
         return eden.thrift.create_thrift_client(self.tmp_dir)