Update package.py

packages/nglview/package.py

@@ -20,4 +20,10 @@ class Nglview(PythonPackage):
     depends_on('py-jupyter-packaging')
     depends_on('py-versioneer')
     depends_on('py-numpy', type=('run'))
-    depends_on('py-ipywidgets', type=('run'))
\ No newline at end of file
+    depends_on('py-ipywidgets', type=('run'))
+
+    # Test
+    @run_after('install')
+    @on_package_attributes(run_tests=True)
+    def check_install (self):
+        python("-c", 'import nglview')