Expand tests of .res_marg

Author: khaeru

message_ix_models/tests/tools/test_res_marg.py

@@ -1,15 +1,30 @@
+from subprocess import CalledProcessError, check_call
+
 import pytest
 
 from message_ix_models.tools.res_marg import main
 
 
-@pytest.mark.xfail(reason="Incomplete test")
 def test_cli() -> None:
-    # TODO Complete
-    assert False
+    """Run :func:`.res_marg.main` via its command-line interface."""
+    command = [
+        "python",
+        "-m",
+        "message_ix_models.tools.res_marg",
+        "--version=123",
+        "model_name",
+        "scenario_name",
+    ]
+
+    # Fails: the model name, scenario name, and version do not exit
+    with pytest.raises(CalledProcessError):
+        check_call(command)
+
 
+@pytest.mark.xfail(reason="Function does not run on the snapshot")
+def test_main(loaded_snapshot) -> None:
+    """Run :func:`.res_marg.main` on the snapshot scenarios."""
+    scen = loaded_snapshot
 
-@pytest.mark.xfail(reason="Incomplete test")
-def test_main() -> None:
-    # TODO Complete
-    main()
+    # Function runs
+    main(scen, None)