Bug#980050: (no subject)

[Gordon Ball]

A sufficient patch is

```
diff --git a/debian/tests/control b/debian/tests/control
index bc03117..d765359 100644
--- a/debian/tests/control
+++ b/debian/tests/control
@@ -1,4 +1,4 @@
-Test-Command: pytest-3
+Test-Command: pytest-3 -k 'not nmr.ipynb'
 Depends: python3-mdtraj,
   python3-ipykernel,
   python3-jupyter-client,
```