Add rough check that caldb is available

Doesn't really check that though, just sees if max-exfl017 is reachable

tests/conftest.py

+import subprocess
 from pathlib import Path
 
 import pytest
+import subprocess
 
 
 def pytest_addoption(parser):
@@ -11,10 +13,23 @@ def pytest_addoption(parser):
         help="Skips tests marked as requiring GPFS access",
     )
 
+    parser.addoption(
+        "--no-caldb",
+        action="store_true",
+        default=False,
+        help="Skips tests marked as requiring calDBs",
+    )
+
 
 def pytest_configure(config):
     config.addinivalue_line(
-        "markers", "requires_gpfs(): marks skips for tests that require GPFS access"
+        "markers",
+        "requires_gpfs(): marks skips for tests that require GPFS access",
+    )
+
+    config.addinivalue_line(
+        "markers",
+        "requires_caldb(): marks skips for tests that require calDB access",
     )
 
 
@@ -23,3 +38,14 @@ def pytest_runtest_setup(item):
         not Path("/gpfs").is_dir() or item.config.getoption("--no-gpfs")
     ):
         pytest.skip("gpfs not available")
+
+    server_available = True
+    try:
+        subprocess.check_output("ping max-exfl017 -c 1", shell=True)
+    except subprocess.CalledProcessError:
+        server_available = False
+
+    if (
+        list(item.iter_markers(name="requires_caldb")) and not server_available
+    ) or item.config.getoption("--no-caldb"):
+        pytest.skip("caldb not available")