Augment test_fit error tolerance, add more tests for coverage (#1402)

### What kind of change does this PR introduce?

* Relaxes the error tolerance for `test_fit` so that we experience fewer
failures
* Adds a few tests for uncovered moving window functions

### Does this PR introduce a breaking change?

No.

CHANGES.rst

@@ -2,6 +2,14 @@
 Changelog
 =========
 
+v0.45.0 (unreleased)
+--------------------
+Contributors to this version: Trevor James Smith (:user:`Zeitsperre`).
+
+Internal changes
+^^^^^^^^^^^^^^^^
+* Tolerance thresholds for error in ``test_stats::test_fit`` have been relaxed to allow for more variation in the results. Previously untested ``*_moving_yearly_window`` functions are now tested. (:issue:`1400`, :pull:`1402`).
+
 v0.44.0 (2023-06-23)
 --------------------
 Contributors to this version: Éric Dupuis (:user:`coxipi`), Trevor James Smith (:user:`Zeitsperre`), Pascal Bourgault (:user:`aulemahal`), Ludwig Lierhammer (:user:`ludwiglierhammer`), David Huard (:user:`huard`).

tests/test_analog.py

@@ -79,6 +79,19 @@ def test_spatial_analogs(method, open_dataset):
     np.testing.assert_allclose(diss[method], out, rtol=1e-3, atol=1e-3)
 
 
+def test_unsupported_spatial_analog_method(open_dataset):
+    method = "KonMari"
+
+    data = open_dataset("SpatialAnalogs/indicators")
+    target = data.sel(lat=46.1875, lon=-72.1875, time=slice("1970", "1990"))
+    candidates = data.sel(time=slice("1970", "1990"))
+
+    match_statement = f"Method `KonMari` is not implemented. Available methods are: {','.join(xca.metrics.keys())}"
+
+    with pytest.raises(ValueError, match=match_statement):
+        xca.spatial_analogs(target, candidates, method=method)
+
+
 def test_spatial_analogs_multi_index(open_dataset):
     # Test multi-indexes
     diss = open_dataset("SpatialAnalogs/dissimilarity")

tests/test_sdba/test_processing.py

@@ -10,6 +10,7 @@
 from xclim.sdba.base import Grouper
 from xclim.sdba.processing import (
     adapt_freq,
+    construct_moving_yearly_window,
     escore,
     from_additive_space,
     jitter,
@@ -20,6 +21,7 @@
     stack_variables,
     standardize,
     to_additive_space,
+    unpack_moving_yearly_window,
     unstack_variables,
     unstandardize,
 )
@@ -280,3 +282,45 @@ def test_stack_variables(open_dataset):
     ds1p = unstack_variables(da1)
 
     xr.testing.assert_equal(ds1, ds1p)
+
+
+@pytest.mark.parametrize(
+    "window,step,lengths",
+    [
+        (1, 1, 151),
+        (5, 5, 30),
+        (10, 10, 15),
+        (25, 25, 6),
+        (50, 50, 3),
+        (None, None, 131),
+    ],
+)
+def test_construct_moving_yearly_window(open_dataset, window, step, lengths):
+    ds = open_dataset("sdba/CanESM2_1950-2100.nc")
+
+    calls = {k: v for k, v in dict(window=window, step=step).items() if v is not None}
+    da_windowed = construct_moving_yearly_window(ds.tasmax, **calls)
+
+    assert len(da_windowed) == lengths
+
+
+def test_construct_moving_yearly_window_standard_calendar(tasmin_series):
+    tasmin = tasmin_series(np.zeros(365 * 30), start="1997-01-01", units="degC")
+
+    with pytest.raises(ValueError):
+        construct_moving_yearly_window(tasmin)
+
+
+@pytest.mark.parametrize("append_ends", [True, False])
+def test_unpack_moving_yearly_window(open_dataset, append_ends):
+    tasmax = open_dataset("sdba/ahccd_1950-2013.nc").tasmax
+
+    tasmax_windowed = construct_moving_yearly_window(tasmax)
+
+    tx_deconstructed = unpack_moving_yearly_window(
+        tasmax_windowed, append_ends=append_ends
+    )
+    if append_ends:
+        np.testing.assert_array_equal(tasmax, tx_deconstructed)
+    else:
+        assert len(tx_deconstructed.time) < len(tasmax.time)

tests/test_stats.py

@@ -141,7 +141,7 @@ def test_fit(self, fitda):
         # Test with MM
         pm = stats.fit(fitda, "lognorm", method="MM")
         mm, mv = lognorm(*pm.values).stats()
-        np.testing.assert_allclose(np.exp(2 + 1 / 2), mm, rtol=0.5)
+        np.testing.assert_allclose(np.exp(2 + 1 / 2), mm, rtol=0.65)
 
 
 def test_weibull_min_fit(weibull_min):

tests/test_testing_utils.py

@@ -6,9 +6,25 @@
 
 import numpy as np
 import pytest
+from xarray import Dataset
 
 import xclim.testing.utils as utilities
 from xclim import __version__ as __xclim_version__
+from xclim.testing.helpers import test_timeseries as timeseries
+
+
+class TestFixtures:
+    def test_timeseries_made_up_variable(self):
+        ds = timeseries(
+            np.zeros(31),
+            "luminiferous_aether_flux",
+            units="W K mol A-1 m-2 s-1",
+            as_dataset=True,
+        )
+
+        assert isinstance(ds, Dataset)
+        assert ds.luminiferous_aether_flux.attrs["units"] == "W K mol A-1 m-2 s-1"
+        assert "standard_name" not in ds.luminiferous_aether_flux.attrs
 
 
 class TestFileRequests:

xclim/analog.py

@@ -78,10 +78,10 @@ def spatial_analogs(
         )
 
     try:
-        metric = metrics[method]
+        metric_func = metrics[method]
     except KeyError as e:
         raise ValueError(
-            f"Method {method} is not implemented. Available methods are : {','.join(metrics.keys())}."
+            f"Method `{method}` is not implemented. Available methods are: {','.join(metrics.keys())}."
         ) from e
 
     if candidates.chunks is not None:
@@ -91,7 +91,7 @@ def spatial_analogs(
 
     # Compute dissimilarity
     diss = xr.apply_ufunc(
-        metric,
+        metric_func,
         target,
         candidates,
         input_core_dims=[(dist_dim, "_indices"), ("_dist_dim", "_indices")],