Add tmpdirs and initial build so test works with xdist

tests/midi_test_helpers.py

@@ -1,6 +1,32 @@
 # Copyright 2024 XMOS LIMITED.
 # This Software is subject to the terms of the XMOS Public Licence: Version 1.
 
+import contextlib
+import os
+import shutil
+import tempfile
+
+MIDI_TEST_CONFIGS = ["xs2", "xs3"]
+MIDI_RATE = 31250
+
+@contextlib.contextmanager
+def cd(newdir, cleanup=lambda: True):
+    prevdir = os.getcwd()
+    os.chdir(os.path.expanduser(newdir))
+    try:
+        yield
+    finally:
+        os.chdir(prevdir)
+        cleanup()
+
+@contextlib.contextmanager
+def tempdir():
+    dirpath = tempfile.mkdtemp()
+    def cleanup():
+        shutil.rmtree(dirpath)
+    with cd(dirpath, cleanup):
+        yield dirpath
+
 class midi_expect_tx:
     def __init(self):
         pass
@@ -12,7 +38,7 @@ class midi_expect_tx:
                 command.append(0)
             expected += "uart_tx_checker: " + " ".join([f"0x{byte:02x}" for byte in command]) + "\n"
 
-        return expected
+        return expected + "\n"
 
 class midi_expect_rx:
     def __init(self):
@@ -25,7 +51,7 @@ class midi_expect_rx:
                 command.append(0)
             expected += "dut_midi_rx: " + " ".join([f"{byte}" for byte in command]) + "\n"
 
-        return expected
+        return expected + "\n"
 
 midi_tx_file = "midi_tx_cmds.txt"
 midi_rx_file = "midi_rx_cmds.txt"
@@ -44,3 +70,12 @@ def create_midi_rx_file(num_commands=0):
     with open(midi_rx_file, "wt") as mr:
         text = f"{num_commands}\n"
         mr.write(text)
+
+
+
+# Test/dev only
+if __name__ == "__main__":
+    with tempdir() as td:
+        print(td)
+        create_midi_tx_file()
+        input("PRESS ENTER TO CONTINUE")