add tests

tests/test_jungfraulib.py

 import pytest
 from extra_data import RunDirectory
 
-from cal_tools.jungfraulib import JungfrauCtrl
+from cal_tools.jungfraulib import JungfrauCtrl, validate_dark_runs
 
 # TODO: replace with mocked RAW data as in tests/test_agipdlib.py
 JF = JungfrauCtrl(
@@ -45,3 +45,22 @@ def test_get_gain_setting(settings, result):
 def test_get_gain_mode(mode, result):
     JF.run_mode = mode
     assert JF.get_gain_mode() == result
+
+@pytest.mark.parametrize(
+    'original_runs,sorted_runs',
+    [
+        ([9035, 9036, 9037], [9035, 9036, 9037]),
+        ([9035, 9037, 9036], [9035, 9036, 9037]),
+        ([9033, 9032, 9031], [9031, 9032, 9033]),
+        ([9033, 9031, 9032], [9031, 9032, 9033]),
+    ]
+)
+# TODO: missing fixed gain dark runs for JUNGFRAU from test proposal.
+# TODO: missing fixed and adaptive runs after the JF control updated.
+def test_validate_dark_runs(original_runs, sorted_runs):
+    raw_folder = "/gpfs/exfel/exp/CALLAB/202130/p900203/raw"
+    validated_runs = validate_dark_runs(
+        raw_folder=raw_folder,
+        runs=original_runs,
+        ctrl_src="FXE_XAD_JF1M/DET/CONTROL")
+    assert validated_runs == sorted_runs