make gimli.units an optional requirement

Author: mcflugen

noxfile.py

@@ -14,8 +14,8 @@
 @nox.session(python=PYTHON_VERSION, venv_backend="conda")
 def test(session: nox.Session) -> None:
     """Run the tests."""
-    session.conda_install("gimli.units", channel=["nodefaults", "conda-forge"])
     session.install(".[testing]")
+    session.conda_install("gimli.units", channel=["nodefaults", "conda-forge"])
 
     args = ["--cov", PROJECT, "-vvv"] + session.posargs
 
@@ -30,11 +30,10 @@ def test(session: nox.Session) -> None:
 @nox.session(name="test-cli", python=PYTHON_VERSION, venv_backend="conda")
 def test_cli(session: nox.Session) -> None:
     """Run the tests."""
-    session.install("model-metadata")
+    session.install(".")
     session.conda_install(
         "gimli.units", "pymt_topography", channel=["nodefaults", "conda-forge"]
     )
-    session.install(".")
 
     session.run("bmi-test", "pymt_topography:Topography")
 

pyproject.toml

@@ -31,7 +31,6 @@ classifiers = [
     "Topic :: Scientific/Engineering :: Physics",
 ]
 dependencies = [
-    "gimli.units",
     "importlib-resources; python_version < '3.12'",
     "model-metadata>=0.8",
     "numpy",
@@ -48,6 +47,9 @@ dynamic = [
 text = "MIT"
 
 [project.optional-dependencies]
+units = [
+	"gimli.units"
+]
 dev = [
     "black",
     "flake8",

requirements.txt

@@ -1,4 +1,3 @@
-gimli.units
 model_metadata
 numpy
 pytest

src/bmi_tester/_tests/stage_1/time_test.py

@@ -6,6 +6,7 @@
 import pytest
 from pytest import approx
 
+from bmi_tester.api import WITH_GIMLI_UNITS
 from bmi_tester.api import check_unit_is_dimensionless
 from bmi_tester.api import check_unit_is_time
 from bmi_tester.api import check_unit_is_valid
@@ -35,7 +36,7 @@ def test_time_units_is_str(initialized_bmi):
     assert isinstance(units, str)
 
 
-# @pytest.mark.skipif(cfunits is None, reason="cfunits is broken on this platform")
+@pytest.mark.skipif(not WITH_GIMLI_UNITS, reason="gimli.units is not installed")
 def test_time_units_is_valid(initialized_bmi):
     """Test the units of time are valid."""
     units = initialized_bmi.get_time_units()

src/bmi_tester/_tests/stage_2/var_test.py

@@ -1,6 +1,7 @@
 import numpy as np
 import pytest
 
+from bmi_tester.api import WITH_GIMLI_UNITS
 from bmi_tester.api import check_unit_is_valid
 
 
@@ -52,6 +53,7 @@ def test_get_var_type(initialized_bmi, var_name):
         raise AssertionError(f"get_var_type: bad data type name ({dtype})")
 
 
+@pytest.mark.skipif(not WITH_GIMLI_UNITS, reason="gimli.units is not installed")
 def test_get_var_units(initialized_bmi, var_name):
     """Test the units of the variables."""
     units = initialized_bmi.get_var_units(var_name)

src/bmi_tester/api.py

@@ -3,16 +3,22 @@
 from collections.abc import Iterable
 from collections.abc import Sequence
 
-import gimli
+try:
+    import gimli
+except ImportError:
+    WITH_GIMLI_UNITS = False
+    SECONDS = None
+else:
+    WITH_GIMLI_UNITS = True
+    SECONDS = gimli.units.Unit("s")
+
 import pytest
 
 if sys.version_info >= (3, 12):  # pragma: no cover (PY12+)
     from importlib.resources import files
 else:  # pragma: no cover (<PY312)
     from importlib_resources import files
 
-SECONDS = gimli.units.Unit("s")
-
 
 def check_bmi(
     package: str,

tests/units_test.py

@@ -1,31 +1,37 @@
 import pytest
 
+from bmi_tester.api import WITH_GIMLI_UNITS
 from bmi_tester.api import check_unit_is_dimensionless
 from bmi_tester.api import check_unit_is_time
 from bmi_tester.api import check_unit_is_valid
 
 
+@pytest.mark.skipif(not WITH_GIMLI_UNITS, reason="gimli.units is not installed")
 @pytest.mark.parametrize(
     "unit", ("m", "m / s", "m s-1", "N m", "N.m", "m^2", "m2", "", "1")
 )
 def test_check_valid_units(unit):
     assert check_unit_is_valid(unit)
 
 
+@pytest.mark.skipif(not WITH_GIMLI_UNITS, reason="gimli.units is not installed")
 @pytest.mark.parametrize("unit", ("foo", "m ** 2", "-"))
 def test_check_invalid_units(unit):
     assert not check_unit_is_valid(unit)
 
 
+@pytest.mark.skipif(not WITH_GIMLI_UNITS, reason="gimli.units is not installed")
 @pytest.mark.parametrize("unit", ("", "1"))
 def test_dimensionless_units(unit):
     assert check_unit_is_dimensionless(unit)
 
 
+@pytest.mark.skipif(not WITH_GIMLI_UNITS, reason="gimli.units is not installed")
 def test_not_dimensionless_units():
     assert not check_unit_is_dimensionless("m")
 
 
+@pytest.mark.skipif(not WITH_GIMLI_UNITS, reason="gimli.units is not installed")
 @pytest.mark.parametrize(
     "unit",
     (
@@ -42,5 +48,6 @@ def test_time_units(unit):
     assert check_unit_is_time(unit)
 
 
+@pytest.mark.skipif(not WITH_GIMLI_UNITS, reason="gimli.units is not installed")
 def test_not_time_units():
     assert not check_unit_is_time("m")