new test led to discovery of new bug in tanimoto

nomad_dos_fingerprints/DOSfingerprint.py

@@ -29,6 +29,8 @@ class DOSFingerprint():
         """
         Performs stepwise numerical integration of ``ys`` over the range of ``xs``. The stepsize of the generated histogram is controlled by DOSFingerprint().stepsize.
         """
+        if len(xs) < 2 or len(ys) < 2:
+            raise ValueError('Invalid input. Please provide arrays with len > 2.')
         xstart = round(int(xs[0] / (self.stepsize * 1.)) * self.stepsize, 8)  # define the limits that fit with the predefined stepsize
         xstop = round(int(xs[-1] / (self.stepsize * 1.)) * self.stepsize, 8)
         x_interp = np.arange(xstart, xstop + self.stepsize, self.stepsize)

tests/test_similarity.py

-import pytest
+import pytest, os, json
 from bitarray import bitarray
 from nomad_dos_fingerprints import tanimoto_similarity, DOSFingerprint
+from nomad_dos_fingerprints.DOSfingerprint import ELECTRON_CHARGE
+
+with open(os.path.join(os.path.dirname(__file__), 'fingerprint_generation_test_data.json'), 'r') as test_data_file:
+    test_data = json.load(test_data_file)
 
 def test_tanimoto():
     # generate fp-type data and check if this can be realized with binary-strings only
@@ -16,3 +20,13 @@ def test_tanimoto():
     assert tanimoto_similarity(fp1, fp2) == 1
     assert tanimoto_similarity(fp1, fp1) == 1
     assert tanimoto_similarity(fp2, fp2) == 1
+
+def test_matching_of_spectra():
+    data = test_data["17661:2634879"]
+    cut_energies = []
+    cut_dos = []
+    cut_energies = [e for e,d in zip(data['dos_energies'], data['dos_values'][0]) if (e / ELECTRON_CHARGE > -4 and e / ELECTRON_CHARGE < 2)]
+    cut_dos = [d for e,d in zip(data['dos_energies'], data['dos_values'][0]) if (e / ELECTRON_CHARGE > -4 and e / ELECTRON_CHARGE < 2)]
+    fp = DOSFingerprint().calculate(data['dos_energies'], data['dos_values'])
+    cut_fp = DOSFingerprint().calculate(cut_energies, [cut_dos])
+    assert tanimoto_similarity(fp, cut_fp) == 1
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