tests: also check disk_read and disk_write for live stats (#366)

At least with jobacct_gather/linux, they should always show something.

Author: tazend

tests/integration/test_job.py

@@ -184,12 +184,16 @@ def test_load_stats(submit_job):
     assert isinstance(job.stats, JobStatistics)
     assert job.stats.elapsed_cpu_time > 0
     assert job.stats.resident_memory > 0
+    assert job.stats.disk_read > 0
+    assert job.stats.disk_write > 0
 
     for step in job.steps.values():
         assert step.stats
         assert step.state == "RUNNING"
         assert isinstance(step.stats, JobStepStatistics)
         assert step.stats.avg_resident_memory > 0
+        assert step.stats.avg_disk_read > 0
+        assert step.stats.avg_disk_write > 0
         assert step.stats.elapsed_cpu_time > 0