test: Insert default test class for ModIO

The standard tests provide a prepared process image and a defined
config.rsc.

tests/__init__.py

@@ -0,0 +1,44 @@
+# -*- coding: utf-8 -*-
+"""Shared functions for tests."""
+__author__ = "Sven Sager"
+__copyright__ = "Copyright (C) 2024 Sven Sager"
+__license__ = "GPLv2"
+
+from os.path import dirname, join
+from tempfile import NamedTemporaryFile
+from unittest import TestCase
+
+import revpimodio2
+
+DEFAULT_PROCIMG = join(dirname(__file__), "proc.img")
+RUN_ON_REVPI = False  # todo: Check revpi system
+
+
+class TestRevPiModIO(TestCase):
+
+    data_dir = dirname(__file__)
+
+    def setUp(self):
+        self.fh_procimg = NamedTemporaryFile("wb+", 0, prefix="test_procimg_")
+        self.fh_procimg.write(b"\x00" * 4096)
+        self.fh_procimg.seek(0)
+
+    def tearDown(self):
+        self.fh_procimg.close()
+
+    def modio(self, **kwargs):
+        """Default ModIO object with temp process image."""
+        if not RUN_ON_REVPI:
+            if "procimg" in kwargs:
+                # Use a copy of given prepared process image
+                with open(kwargs["procimg"], "rb") as fh:
+                    self.fh_procimg.write(fh.read())
+                    self.fh_procimg.seek(0)
+
+            # Always use the temporary process image of testing class
+            kwargs["procimg"] = self.fh_procimg.name
+
+            # Always use a config inside the testing folder (default config.rsc)
+            kwargs["configrsc"] = join(self.data_dir, kwargs.get("configrsc", "config.rsc"))
+
+        return revpimodio2.RevPiModIO(**kwargs)