added test for spahm-b (water)

tests/test_spahm_b.py

@@ -0,0 +1,22 @@
+import os
+import numpy as np
+from qstack.spahm.rho import bond, utils
+from qstack import compound
+
+def test_water():
+    path = os.path.dirname(os.path.realpath(__file__))
+    xyz_in = path+'/data/H2O.xyz'
+    mols = utils.load_mols([xyz_in], [0], [0], 'minao')
+    dms = utils.mols_guess(mols, [xyz_in], 'LB', spin=[0])
+    X = bond.bond(mols, dms, spin=[0])
+    X = np.hstack(X) # merging alpha-beta components for spin unrestricted representation #TODO: should be included into function not in main
+    true_file = path+'/data/H2O_spahm_b.npy_alpha_beta.npy'
+    X_true = np.load(true_file)
+    assert(X_true.shape == X.shape)
+    for Xa, Xa_true in zip(X, X_true):
+        assert(np.linalg.norm(Xa-Xa_true) < 1e-8) # evaluating representation diff as norm (threshold = 1e-8)
+
+
+if __name__ == '__main__':
+    test_water()
+