Refactor unit_conversions around plib.

Author: Eli

tests/test_unit_conversions.py

@@ -0,0 +1,168 @@
+import os
+import math
+import numpy as np
+import pandas as pd
+import pytest
+import importlib.util
+
+import vtools.functions.unit_conversions as uc
+
+
+# -----------------------------------------------------------------------------
+# Linear / affine converters
+# -----------------------------------------------------------------------------
+@pytest.mark.parametrize("x", [123.456, np.array([0.0, 1.0, 10.0, 123.456])])
+def test_m_ft_roundtrip(x):
+    ft = uc.m_to_ft(x)
+    m = uc.ft_to_m(ft)
+    np.testing.assert_allclose(m, x, rtol=0, atol=1e-12)
+
+
+@pytest.mark.parametrize("x", [7.5, np.array([0.0, 1.0, 2.5, 1000.0])])
+def test_cms_cfs_roundtrip(x):
+    cfs = uc.cms_to_cfs(x)
+    cms = uc.cfs_to_cms(cfs)
+    np.testing.assert_allclose(cms, x, rtol=0, atol=1e-12)
+
+
+def test_temperature_roundtrip():
+    c = np.array([-40.0, 0.0, 20.0, 37.0, 100.0])
+    f = uc.celsius_to_fahrenheit(c)
+    c2 = uc.fahrenheit_to_celsius(f)
+    np.testing.assert_allclose(c2, c, rtol=0, atol=1e-12)
+
+
+# -----------------------------------------------------------------------------
+# Series / DataFrame preservation
+# -----------------------------------------------------------------------------
+@pytest.fixture
+def sample_series_df():
+    idx = pd.date_range("2020-01-01", periods=4, freq="h")
+    ser = pd.Series([0.0, 1.0, 2.0, 3.0], index=idx, name="flow")
+    df = pd.DataFrame(
+        {"a": [0.0, 1.0, 2.0, 3.0], "b": [10.0, 11.0, 12.0, 13.0]},
+        index=idx,
+    )
+    return ser, df
+
+
+def test_series_conversion(sample_series_df):
+    ser, _ = sample_series_df
+    out = uc.convert_units(ser, "m", "ft")
+    assert isinstance(out, pd.Series)
+    assert out.index.equals(ser.index)
+    assert out.name == ser.name
+    np.testing.assert_allclose(out.values, ser.values * uc.M2FT, atol=1e-12)
+
+
+def test_dataframe_conversion(sample_series_df):
+    _, df = sample_series_df
+    out = uc.convert_units(df, "ft^3 s-1", "m^3 s-1")
+    assert isinstance(out, pd.DataFrame)
+    assert out.index.equals(df.index)
+    assert (out.columns == df.columns).all()
+    np.testing.assert_allclose(out.values, df.values * uc.CFS2CMS, atol=1e-12)
+# ----------------------------------------------------------------import importlib.util
+
+@pytest.mark.skipif(
+    importlib.util.find_spec("cf_units") is None,
+    reason="cf_units not installed")
+def test_optional_cf_units_backend(monkeypatch):
+    x = np.array([0.0, 1.0, 3.0])
+    monkeypatch.setenv("VTOOLS_UNITS_BACKEND", "cf_units")
+    out = uc.convert_units(x, "m", "ft")
+    np.testing.assert_allclose(out, x * uc.M2FT, atol=1e-12)
+    monkeypatch.delenv("VTOOLS_UNITS_BACKEND", raising=False)
+
+
+
+
+# Aliases, backend consistency
+# -----------------------------------------------------------------------------
+@pytest.mark.parametrize("alias", ["cfs", "ft3/s", "ft^3/s"])
+def test_aliases_cfs_to_cms(alias):
+    x = np.array([0.0, 35.31466621, 353.1466621])
+    out = uc.convert_units(x, alias, "m^3 s-1")
+    expected = x * uc.CFS2CMS
+    np.testing.assert_allclose(out, expected, atol=1e-12)
+
+
+@pytest.mark.parametrize("alias", ["cms", "m3/s", "m^3/s"])
+def test_aliases_cms_to_cfs(alias):
+    x = np.array([0.0, 1.0, 10.0])
+    out = uc.convert_units(x, alias, "ft^3 s-1")
+    expected = x * uc.CMS2CFS
+    np.testing.assert_allclose(out, expected, atol=1e-12)
+
+
+def test_aliases_temperature():
+    x = np.array([32.0, 212.0])
+    out = uc.convert_units(x, "deg F", "degC")
+    expected = uc.fahrenheit_to_celsius(x)
+    np.testing.assert_allclose(out, expected, atol=1e-12)
+
+
+@pytest.mark.parametrize("alias", ["us/cm", "μs/cm", "micromhos/cm"])
+def test_aliases_conductivity(alias):
+    x = np.array([0.0, 500.0, 5000.0, 50000.0])
+    out = uc.convert_units(x, alias, "psu")
+    direct = uc.ec_psu_25c(x, hill_correction=True)
+    np.testing.assert_allclose(out, direct, atol=1e-12)
+
+
+def test_backend_consistency_with_constants():
+    x = np.array([0.0, 1.23, 10.0, 123.45])
+
+    # m <-> ft
+    np.testing.assert_allclose(uc.convert_units(x, "m", "ft"), x * uc.M2FT, atol=1e-12)
+    np.testing.assert_allclose(uc.convert_units(x, "ft", "m"), x * uc.FT2M, atol=1e-12)
+
+    # cfs <-> cms
+    np.testing.assert_allclose(
+        uc.convert_units(x, "ft^3 s-1", "m^3 s-1"), x * uc.CFS2CMS, atol=1e-12
+    )
+    np.testing.assert_allclose(
+        uc.convert_units(x, "m^3 s-1", "ft^3 s-1"), x * uc.CMS2CFS, atol=1e-12
+    )
+
+
+#@pytest.mark.skipif(
+#    not pytest.importorskip("cf_units", reason="cf_units not installed"),
+#    reason="cf_units not available",
+#)
+#def test_optional_cf_units_backend(monkeypatch):
+#    x = np.array([0.0, 1.0, 3.0])
+#    monkeypatch.setenv("VTOOLS_UNITS_BACKEND", "cf_units")
+#    out = uc.convert_units(x, "m", "ft")
+#    np.testing.assert_allclose(out, x * uc.M2FT, atol=1e-12)
+#    monkeypatch.delenv("VTOOLS_UNITS_BACKEND", raising=False)
+
+
+# -----------------------------------------------------------------------------
+# EC↔PSU consistency
+# -----------------------------------------------------------------------------
+def test_convert_units_matches_ec_psu():
+    ec = np.array([0.0, 100.0, 1000.0, 50000.0])
+    a = uc.convert_units(ec, "us/cm", "psu")
+    b = uc.ec_psu_25c(ec, hill_correction=True)
+    np.testing.assert_allclose(a, b, atol=1e-12)
+
+
+def test_convert_units_matches_psu_ec():
+    psu = np.array([0.0, 1.0, 10.0, 33.0])
+    a = uc.convert_units(psu, "psu", "us/cm")
+    b = uc.psu_ec_25c(psu, refine=True, hill_correction=True)
+    np.testing.assert_allclose(a, b, atol=1e-9)  # root-finder tolerance
+
+
+def test_negative_ec_behavior():
+    # Scalar negative → NaN
+    assert math.isnan(uc.ec_psu_25c(-5.0))
+    assert math.isnan(uc.convert_units(-5.0, "us/cm", "psu"))
+
+    # Array: negative entries become NaN
+    ec = np.array([-5.0, 0.0, 10.0])
+    out1 = uc.ec_psu_25c(ec)
+    out2 = uc.convert_units(ec, "us/cm", "psu")
+    assert np.isnan(out1[0]) and np.isnan(out2[0])
+    np.testing.assert_allclose(out1[1:], out2[1:], atol=1e-12)