Resolve "release v2.3.0"

Closes #440 (closed)

test/test_helpers/test_statistics.py

@@ -375,6 +375,7 @@ class TestCalculateErrorMetrics:
         x_array1 = xr.DataArray(d1, coords=coords, dims=coords.keys())
         x_array2 = xr.DataArray(d2, coords=coords, dims=coords.keys())
         expected = {"mse": xr.DataArray(np.array([1, 2, 0, 0, 1./3]), coords={"value": [0, 1, 2, 3, 4]}, dims=["value"]),
+                    "me": xr.DataArray(np.array([-1./3, -2./3, 0, 0, -1./3]), coords={"value": [0, 1, 2, 3, 4]}, dims=["value"]),
                     "rmse": np.sqrt(xr.DataArray(np.array([1, 2, 0, 0, 1./3]), coords={"value": [0, 1, 2, 3, 4]}, dims=["value"])),
                     "mae": xr.DataArray(np.array([1, 4./3, 0, 0, 1./3]), coords={"value": [0, 1, 2, 3, 4]}, dims=["value"]),
                     "ioa": xr.DataArray(np.array([0.3721, 0.4255, 1, 1, 0.4706]), coords={"value": [0, 1, 2, 3, 4]}, dims=["value"]),
@@ -383,6 +384,7 @@ class TestCalculateErrorMetrics:
         assert check_nested_equality(expected, calculate_error_metrics(x_array1, x_array2, "index"), 3) is True
 
         expected = {"mse": xr.DataArray(np.array([1.2, 0.4, 0.4]), coords={"index": [0, 1, 2]}, dims=["index"]),
+                    "me": xr.DataArray(np.array([-0.8, -0.4, 0.4]), coords={"index": [0, 1, 2]}, dims=["index"]),
                     "rmse": np.sqrt(xr.DataArray(np.array([1.2, 0.4, 0.4]), coords={"index": [0, 1, 2]}, dims=["index"])),
                     "mae": xr.DataArray(np.array([0.8, 0.4, 0.4]), coords={"index": [0, 1, 2]}, dims=["index"]),
                     "ioa": xr.DataArray(np.array([0.8478, 0.9333, 0.9629]), coords={"index": [0, 1, 2]}, dims=["index"]),