fixup test_environment: improve error reporting

Author: mr-c

tests/test_environment.py

@@ -62,7 +62,9 @@ def assert_env_matches(
         if not env_accepts_null():
             e.pop("LC_CTYPE", None)
             e.pop("__CF_USER_TEXT_ENCODING", None)
-        assert len(e) == 0, f"Unexpected environment variable(s): {', '.join(e.keys())}"
+        assert (
+            len(e) == 0
+        ), f"Unexpected environment variable(s): {', '.join(e.keys())} from env {env}."
 
 
 class CheckHolder(ABC):
@@ -122,6 +124,10 @@ def HOME(v: str, env: Env) -> bool:
 class Singularity(CheckHolder):
     """Run in a Singularity container."""
 
+    @staticmethod
+    def get_sing_version() -> Version:
+        return Version(".".join(map(str, get_version()[0])))
+
     @staticmethod
     def checks(tmp_prefix: str) -> EnvChecks:
         """Create checks."""
@@ -139,7 +145,7 @@ def PWD(v: str, env: Env) -> bool:
         }
 
         # Singularity variables appear to be in flux somewhat.
-        version = Version(".".join(map(str, get_version()[0])))
+        version = Singularity.get_sing_version()
         assert version >= Version("3"), "Tests only work for Singularity 3+"
         sing_vars: EnvChecks = {
             "SINGULARITY_CONTAINER": None,
@@ -308,9 +314,15 @@ def test_preserve_all(
 
     for vname, val in env.items():
         try:
+            assert vname in checks, env
             assert_envvar_matches(checks[vname], vname, env)
         except KeyError as kerr:
             if vname not in os.environ:
+                if crt_params_ == Singularity:
+                    print(
+                        f"Raw Singularity version: {get_version()}, "
+                        "processed  version: {Singularity.get_sing_version()}."
+                    )
                 raise kerr
             assert val == os.environ[vname]
         except AssertionError:

tests/util.py

@@ -156,7 +156,7 @@ def get_tool_env(
 
     with working_directory(tmp_path):
         rc, stdout, stderr = get_main_output(
-            args,
+            ["--debug"] + args,
             replacement_env=replacement_env,
             extra_env=extra_env,
             monkeypatch=monkeypatch,