skip horace tests if pace_neutrons is not installed, which happens du…

…ring the conda build as package is not on conda

conda/meta.yaml

@@ -32,7 +32,9 @@ test:
 
   {# Conda does not allow spaces between package name and version, so remove them #}
   {% for package in test_dependencies %}
+    {% if package != "pace_neutrons" %}
     - {% if package == "graphviz" %}python-graphviz{% else %}{{ package|replace(" ", "") }}{% endif %}
+    {% endif %}
   {% endfor %}
     # Note that we add tof here because it depends on plopp, and plopp should not be in
     # basetest.in because of the nightly dependencies

tests/io/sqw/sqw_horace_test.py

@@ -8,7 +8,6 @@
 from typing import Any
 
 import numpy as np
-import pace_neutrons
 import pytest
 import scipp as sc
 from dateutil.parser import parse as parse_datetime
@@ -25,9 +24,13 @@
     SqwLineProj,
 )
 
+pytest.importorskip("pace_neutrons")
+
 
 @pytest.fixture(scope="module")
 def matlab() -> Any:
+    import pace_neutrons
+
     try:
         return pace_neutrons.Matlab()
     except RuntimeError as e: