add a consistency check for develop.

tests/test_consistent.py

@@ -0,0 +1,23 @@
+# unit tests for consistent model outputs
+
+import pytest
+
+import sys
+import os
+import numpy as np
+
+from pyDeltaRCM.deltaRCM_driver import pyDeltaRCM
+
+# need to create a simple case of pydeltarcm object to test these functions
+delta = pyDeltaRCM(input_file=os.path.join(os.getcwd(), 'tests', 'test.yaml'))
+
+
+def test_bed_after_one_update():
+    """
+    """
+    delta.update()
+    # slice is: delta.eta[:5, 4]
+    print(delta.eta[:5, 4])
+
+    _exp = np.array([-1., -0.82951754, -0.9981775 , -1., -1.])
+    assert np.all(delta.eta[:5, 4] == pytest.approx(_exp))