[AIRFLOW-5709] Fix regression in setting custom operator resources.
diff --git a/airflow/models/baseoperator.py b/airflow/models/baseoperator.py
index d848c2743227c..5d61e1e77a777 100644
--- a/airflow/models/baseoperator.py
+++ b/airflow/models/baseoperator.py
@@ -372,7 +372,7 @@ def __init__(
                         d=dag.dag_id if dag else "", t=task_id, tr=weight_rule))
         self.weight_rule = weight_rule
 
-        self.resources = Resources(*resources) if resources is not None else None
+        self.resources = Resources(**resources) if resources is not None else None
         self.run_as_user = run_as_user
         self.task_concurrency = task_concurrency
         self.executor_config = executor_config or {}
diff --git a/tests/models/test_baseoperator.py b/tests/models/test_baseoperator.py
index 2716422edc422..9d2b99b33b370 100644
--- a/tests/models/test_baseoperator.py
+++ b/tests/models/test_baseoperator.py
@@ -256,3 +256,12 @@ def test_override_jinja_env_option(self):
 
         result = task.render_template("{{ foo }}", {"foo": "bar"})
         self.assertEqual(result, "bar")
+
+    def test_default_resources(self):
+        task = DummyOperator(task_id="default-resources")
+        self.assertIsNone(task.resources)
+
+    def test_custom_resources(self):
+        task = DummyOperator(task_id="custom-resources", resources={"cpus": 1, "ram": 1024})
+        self.assertEqual(task.resources.cpus.qty, 1)
+        self.assertEqual(task.resources.ram.qty, 1024)

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### Description

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Fix a regression in custom operator resources introduced in #5259, and add basic unit tests of operator resources.

### Tests

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