Use pytest.importorskip for prometheus test
See
@@ -66,6 +66,7 @@ def test_prefix(c, s, a, b):
check_new_threads=False,
scheduler_kwargs={'services': {('bokeh', 0): BokehScheduler}})
def test_prometheus(c, s, a, b):
+ pytest.importorskip('prometheus_client')
http_client = AsyncHTTPClient()
response = yield http_client.fetch('http://localhost:%d/metrics'
% s.services['bokeh'].port)
