Add basic tests of the EBM code.

climlab/tests/test_ebm.py

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+import numpy as np
+import climlab
+import pytest
+
+# The fixtures are reusable pieces of code to set up the input to the tests.
+# Without fixtures, we would have to do a lot of cutting and pasting
+# These fixtures are based on the notebook
+# Seasonal cycle and heat capacity.ipynb
+@pytest.fixture()
+def EBM_seasonal():
+    return climlab.EBM_seasonal(water_depth=10.)
+
+@pytest.fixture()
+def EBM_highobliquity():
+    orb_highobl = {'ecc':0., 'obliquity':90., 'long_peri':0.}
+    return climlab.EBM_seasonal(orb=orb_highobl, water_depth=10.)
+
+@pytest.fixture()
+def EBM_iceline():
+    return climlab.EBM_annual( num_points = 180, a0=0.3, a2=0.078, ai=0.62)
+
+# helper for a common test pattern
+def _check_minmax(array, amin, amax):
+    return (np.allclose(array.min(), amin) and
+            np.allclose(array.max(), amax))
+
+def test_model_creation(EBM_seasonal):
+    """Just make sure we can create a model."""
+    assert len(EBM_seasonal.Ts)==90
+
+#  This is not a great test.. but just sees if we reproduce the same
+#  temperature as in the notebook after 1 year of integration
+def test_integrate_years(EBM_seasonal):
+    """Check that we can integrate forward the model and get the expected
+    surface temperature."""
+    EBM_seasonal.step_forward()
+    EBM_seasonal.integrate_years(1)
+    assert _check_minmax(EBM_seasonal.Ts, -24.21414189, 31.16169215)
+
+#  And do the same thing at high obliquity
+def test_high_obliquity(EBM_highobliquity):
+    """Check that we can integrate forward the model and get the expected
+    surface temperature."""
+    EBM_highobliquity.step_forward()
+    EBM_highobliquity.integrate_years(1)
+    assert _check_minmax(EBM_highobliquity.Ts, -9.28717079958807, 27.37890262018116)
+
+def test_annual_iceline(EBM_iceline):
+    '''Check that the annual mean EBM with interactive ice edge gives expected
+    result (ice at 70degrees).'''
+    EBM_iceline.integrate_years(5.)
+    assert np.all(EBM_iceline.icelat == np.array([-70.,  70.]))
+
+def test_decreased_S0(EBM_iceline):
+    '''Check that a decrease in solar constant to 1200 W/m2 will give a
+    Snowball Earth result in the annual mean EBM.'''
+    EBM_iceline.subprocess['insolation'].S0 = 1200.
+    EBM_iceline.integrate_years(5.)
+    assert np.all(EBM_iceline.icelat == np.array([-0.,  0.]))