Use custom program rather than yes

Yes may be too IO intensive, and may not exist on all systems

tests/__init__.py

@@ -1,4 +1,5 @@
 import functools
+import os
 from multiprocessing import Process
 
 from aiohttp.test_utils import unused_port
@@ -12,6 +13,8 @@ from catfish.utils.sockets import create_base_socket_dir, delete_base_socket_dir
 
 
 class BaseTestCase(AsyncTestCase):
+    DUMMY_EXE = os.path.join(os.path.dirname(__file__), "dummy_program.py")
+
     def setUp(self):
         create_base_socket_dir()
         worker.stop_worker()

tests/dummy_program.py

@@ -0,0 +1,10 @@
+#!/usr/bin/env python3
+
+import sys
+import time
+from itertools import count
+
+for num in count():
+    time.sleep(0.5)
+    sys.stdout.write("Round {}\n".format(num))
+    sys.stdout.flush()

tests/test_router/test_utils.py

@@ -13,7 +13,7 @@ class ProcessForHostnameTestCase(BaseTestCase):
 
     def test_finds_process(self):
         proc = subprocess.Popen(
-            "yes",
+            self.DUMMY_EXE,
             stdout=subprocess.PIPE,
             env={**os.environ, utils.HOSTNAME_ENV_VAR: "localhost"},
         )
@@ -22,7 +22,7 @@ class ProcessForHostnameTestCase(BaseTestCase):
 
     def test_finds_process_with_multiple_hostnames(self):
         proc = subprocess.Popen(
-            "yes",
+            self.DUMMY_EXE,
             stdout=subprocess.PIPE,
             env={**os.environ, utils.HOSTNAME_ENV_VAR: "localhost,test.local"},
         )

tests/test_utils/test_processes.py

@@ -22,7 +22,9 @@ class TerminateProcessesTestCase(BaseTestCase):
     def test_kills_lots_of_processes(self):
         created_processes = []
         for _ in range(10):
-            created_processes.append(subprocess.Popen("yes", stdout=subprocess.PIPE))
+            created_processes.append(
+                subprocess.Popen(self.DUMMY_EXE, stdout=subprocess.PIPE)
+            )
 
         for proc in created_processes:
             self.assertIsNone(proc.poll())

tests/test_worker/test_server.py

@@ -5,7 +5,7 @@ from tests import BaseWorkerTestCase
 
 class WorkerServerTestCase(BaseWorkerTestCase):
     def test_server_creates_process(self):
-        response = send_to_server({"type": "process", "command": "yes"})
+        response = send_to_server({"type": "process", "command": self.DUMMY_EXE})
         self.assertTrue(is_process_running(response["pid"]))
 
     def test_unknown_command_type(self):