Fix devIocStats by including posix headers

This relies on the config_var "POSIX" being defined as True/False for
the current platform.

The test is pretty simple, just the CPU count and IOC CPU load as
they're fairly easy to calculate

setup.py

@@ -41,6 +41,7 @@
 ]
 
 devIocStats_src = os.path.join("softioc", "iocStats", "devIocStats")
+devIocStats_posix = os.path.join(devIocStats_src, "os", "posix")
 devIocStats_os = os.path.join(devIocStats_src, "os", get_config_var('OS_CLASS'))
 devIocStats_default = os.path.join(devIocStats_src, "os", "default")
 
@@ -52,14 +53,26 @@
     else:
         sources.append(os.path.join(devIocStats_default, f))
 
+include_dirs = [
+    epicscorelibs.path.include_path,
+    devIocStats_src,
+    devIocStats_os,
+    devIocStats_default
+]
+
+if get_config_var("POSIX"):
+    # If we're on a POSIX system, insert the POSIX folder into the list after
+    # the os-specific one so that os-specific header files are used first.
+    include_dirs.insert(
+        include_dirs.index(devIocStats_os) + 1,
+        devIocStats_posix
+    )
+
 # Extension with all our C code
 ext = Extension(
     name='softioc._extension',
     sources = sources,
-    include_dirs=[
-        epicscorelibs.path.include_path,
-        devIocStats_src, devIocStats_os, devIocStats_default
-    ],
+    include_dirs = include_dirs,
     dsos = [
         'epicscorelibs.lib.qsrv',
         'epicscorelibs.lib.pvAccessIOC',

tests/test_deviocstats.py

@@ -0,0 +1,70 @@
+# File for tests related to devIocStats support module, which at time of writing
+# is built alongside PythonSoftIOC and optionally turned on at runtime
+
+import multiprocessing
+import pytest
+
+from conftest import (
+    create_random_prefix,
+    TIMEOUT,
+    select_and_recv,
+    get_multiprocessing_context
+)
+
+from softioc import asyncio_dispatcher, builder, softioc
+
+def deviocstats_test_func(
+        device_name,
+        child_conn):
+    """Start the IOC with the specified validate method"""
+
+    builder.SetDeviceName(device_name)
+
+    dispatcher = asyncio_dispatcher.AsyncioDispatcher()
+    builder.LoadDatabase()
+    softioc.devIocStats(device_name)
+    softioc.iocInit(dispatcher)
+
+    child_conn.send("R")
+
+    # Keep process alive while main thread runs CAGET
+    if child_conn.poll(TIMEOUT):
+        val = child_conn.recv()
+        assert val == "D", "Did not receive expected Done character"
+
+def test_deviocstats():
+
+    ctx = get_multiprocessing_context()
+
+    parent_conn, child_conn = ctx.Pipe()
+
+    device_name = create_random_prefix()
+
+    process = ctx.Process(
+        target=deviocstats_test_func,
+        args=(device_name, child_conn),
+    )
+
+    process.start()
+
+    from cothread.catools import caget, _channel_cache
+
+    try:
+        # Wait for message that IOC has started
+        select_and_recv(parent_conn, "R")
+
+        # Suppress potential spurious warnings
+        _channel_cache.purge()
+
+        cpu_cnt = caget(device_name + ":CPU_CNT")
+        assert cpu_cnt == multiprocessing.cpu_count()
+
+        ioc_cpu_load = caget(device_name + ":IOC_CPU_LOAD")
+        assert ioc_cpu_load == pytest.approx(0, abs=1e-2)
+
+
+    finally:
+        # Suppress potential spurious warnings
+        _channel_cache.purge()
+        parent_conn.send("D")  # "Done"
+        process.join(timeout=TIMEOUT)