first attemp at tests for metadata logging

tests.py

@@ -8,6 +8,7 @@ import subprocess
 from pathlib import Path
 
 import pytest
+import logging
 
 mod = importlib.import_module("mpsd-software-environment")
 
@@ -314,6 +315,14 @@ def test_install_environment_zlib():
         lines = f.read()
         assert "zlib" in lines
 
+def test_metadata_logging(tmp_path):
+    mod.set_up_logging("WARNING", tmp_path/"test.log")
+    key = "important_key"
+    value = "important_value"
+    mod.log_metadata(key,value)
+    expected_log = f"{mod.config_vars['metadata_tag_open']}{key}:{value}{mod.config_vars['metadata_tag_close']}"
+    with open(tmp_path/"test.log", "r") as f:
+        assert expected_log in f.read()
 
 def test_interface(tmp_path):
     """Test other things (not implemented yet)."""