Add ICML test

tests/inputs/diffusion.bib

@@ -0,0 +1,15 @@
+@InProceedings{pmlr-v37-sohl-dickstein15,
+  title = 	 {Deep Unsupervised Learning using Nonequilibrium Thermodynamics},
+  author = 	 {Sohl-Dickstein, Jascha and Weiss, Eric and Maheswaranathan, Niru and Ganguli, Surya},
+  booktitle = 	 {Proceedings of the 32nd International Conference on Machine Learning},
+  pages = 	 {2256--2265},
+  year = 	 {2015},
+  editor = 	 {Bach, Francis and Blei, David},
+  volume = 	 {37},
+  series = 	 {Proceedings of Machine Learning Research},
+  address = 	 {Lille, France},
+  month = 	 {07--09 Jul},
+  publisher =    {PMLR},
+  pdf = 	 {http://proceedings.mlr.press/v37/sohl-dickstein15.pdf},
+  url = 	 {https://proceedings.mlr.press/v37/sohl-dickstein15.html},
+}

tests/test_find_dois.py

@@ -51,4 +51,11 @@ def test_tvcg_doi(filename, correct_doi):
 ])
 def test_neurips_doi(filename):
     # NeurIPS does not have a DOI
+    search_and_check_doi(filename, "")
+
+@pytest.mark.parametrize("filename", [
+    ("diffusion.bib"),
+])
+def test_icml_doi(filename):
+    # ICML does not have a DOI
     search_and_check_doi(filename, "")