diff --git a/tests/integration/test_xtrigger_mgr.py b/tests/integration/test_xtrigger_mgr.py
index b4d2d503799..c116e6968a5 100644
--- a/tests/integration/test_xtrigger_mgr.py
+++ b/tests/integration/test_xtrigger_mgr.py
@@ -13,10 +13,13 @@
 #
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
-"""Tests for the behaviour of xtrigger manager.
-"""
+"""Tests for the behaviour of xtrigger manager."""
 
-from pytest_mock import mocker
+import asyncio
+from pathlib import Path
+from textwrap import dedent
+
+from cylc.flow.pathutil import get_workflow_run_dir
 
 async def test_2_xtriggers(flow, start, scheduler, monkeypatch):
     """Test that if an itask has 2 wall_clock triggers with different
@@ -118,4 +121,69 @@ async def test_1_xtrigger_2_tasks(flow, start, scheduler, monkeypatch, mocker):
         # resulting in two calls to put_xtriggers. This test fails
         # on master, but with call count 0 (not 2) because the main
         # loop doesn't run in this test.
-        
+
+
+async def test_xtriggers_restart(flow, start, scheduler, db_select):
+    """It should write xtrigger results to the DB and load them on restart."""
+    # define a workflow which uses a custom xtrigger
+    id_ = flow({
+        'scheduler': {
+            'allow implicit tasks': 'True'
+        },
+        'scheduling': {
+            'xtriggers': {
+                'mytrig': 'mytrig()'
+            },
+            'graph': {
+                'R1': '@mytrig => foo'
+            },
+        }
+    })
+
+    # add a custom xtrigger to the workflow
+    run_dir = Path(get_workflow_run_dir(id_))
+    xtrig_dir = run_dir / 'lib/python'
+    xtrig_dir.mkdir(parents=True)
+    (xtrig_dir / 'mytrig.py').write_text(dedent('''
+        from random import random
+
+        def mytrig(*args, **kwargs):
+            # return a different random number each time
+            return True, {"x": str(random())}
+    '''))
+
+    # start the workflow & run the xtrigger
+    schd = scheduler(id_)
+    async with start(schd):
+        # run all xtriggers
+        for task in schd.pool.get_tasks():
+            schd.xtrigger_mgr.call_xtriggers_async(task)
+        # one xtrigger should have been scheduled to run
+        assert len(schd.proc_pool.queuings) + len(schd.proc_pool.runnings) == 1
+        # wait for it to return
+        for _ in range(50):
+            await asyncio.sleep(0.1)
+            schd.proc_pool.process()
+            if len(schd.proc_pool.runnings) == 0:
+                break
+        else:
+            raise Exception('Process pool did not clear')
+
+    # the xtrigger should be written to the DB
+    db_xtriggers = db_select(schd, True, 'xtriggers')
+    assert len(db_xtriggers) == 1
+    assert db_xtriggers[0][0] == 'mytrig()'
+    assert db_xtriggers[0][1].startswith('{"x":')
+
+    # restart the workflow, the xtrigger should *not* run again
+    schd = scheduler(id_)
+    async with start(schd):
+        # run all xtriggers
+        for task in schd.pool.get_tasks():
+            schd.xtrigger_mgr.call_xtriggers_async(task)
+        # the xtrigger should have been loaded from the DB
+        # (so no xtriggers should be scheduled to run)
+        assert len(schd.proc_pool.queuings) + len(schd.proc_pool.runnings) == 0
+
+    # check the DB to ensure no additional entries have been created
+    assert db_select(schd, True, 'xtriggers') == db_xtriggers