diff --git a/tests/sensors/test_external_task_sensor.py b/tests/sensors/test_external_task_sensor.py
index 6d8920f008d96..376aa27bb16f0 100644
--- a/tests/sensors/test_external_task_sensor.py
+++ b/tests/sensors/test_external_task_sensor.py
@@ -20,6 +20,7 @@
 import itertools
 import logging
 import os
+import re
 import tempfile
 import zipfile
 from datetime import time, timedelta
@@ -29,7 +30,7 @@
 
 from airflow import exceptions, settings
 from airflow.decorators import task as task_deco
-from airflow.exceptions import AirflowException, AirflowSensorTimeout, TaskDeferred
+from airflow.exceptions import AirflowException, AirflowSensorTimeout, AirflowSkipException, TaskDeferred
 from airflow.models import DagBag, DagRun, TaskInstance
 from airflow.models.dag import DAG
 from airflow.models.serialized_dag import SerializedDagModel
@@ -838,6 +839,138 @@ def test_external_task_group_when_there_is_no_TIs(self):
                 ignore_ti_state=True,
             )
 
+    @pytest.mark.parametrize(
+        "kwargs, expected_message",
+        (
+            (
+                {
+                    "external_task_ids": [TEST_TASK_ID, TEST_TASK_ID_ALTERNATE],
+                    "failed_states": [State.FAILED],
+                },
+                f"Some of the external tasks {re.escape(str([TEST_TASK_ID, TEST_TASK_ID_ALTERNATE]))}"
+                f" in DAG {TEST_DAG_ID} failed.",
+            ),
+            (
+                {
+                    "external_task_group_id": [TEST_TASK_ID, TEST_TASK_ID_ALTERNATE],
+                    "failed_states": [State.FAILED],
+                },
+                f"The external task_group '{re.escape(str([TEST_TASK_ID, TEST_TASK_ID_ALTERNATE]))}'"
+                f" in DAG '{TEST_DAG_ID}' failed.",
+            ),
+            (
+                {"failed_states": [State.FAILED]},
+                f"The external DAG {TEST_DAG_ID} failed.",
+            ),
+        ),
+    )
+    @pytest.mark.parametrize(
+        "soft_fail, expected_exception",
+        (
+            (
+                False,
+                AirflowException,
+            ),
+            (
+                True,
+                AirflowSkipException,
+            ),
+        ),
+    )
+    @mock.patch("airflow.sensors.external_task.ExternalTaskSensor.get_count")
+    @mock.patch("airflow.sensors.external_task.ExternalTaskSensor._get_dttm_filter")
+    def test_fail_poke(
+        self, _get_dttm_filter, get_count, soft_fail, expected_exception, kwargs, expected_message
+    ):
+        _get_dttm_filter.return_value = []
+        get_count.return_value = 1
+        op = ExternalTaskSensor(
+            task_id="test_external_task_duplicate_task_ids",
+            external_dag_id=TEST_DAG_ID,
+            allowed_states=["success"],
+            dag=self.dag,
+            soft_fail=soft_fail,
+            deferrable=False,
+            **kwargs,
+        )
+        with pytest.raises(expected_exception, match=expected_message):
+            op.execute(context={})
+
+    @pytest.mark.parametrize(
+        "response_get_current, response_exists, kwargs, expected_message",
+        (
+            (None, None, {}, f"The external DAG {TEST_DAG_ID} does not exist."),
+            (
+                DAG(dag_id="test"),
+                False,
+                {},
+                f"The external DAG {TEST_DAG_ID} was deleted.",
+            ),
+            (
+                DAG(dag_id="test"),
+                True,
+                {"external_task_ids": [TEST_TASK_ID, TEST_TASK_ID_ALTERNATE]},
+                f"The external task {TEST_TASK_ID} in DAG {TEST_DAG_ID} does not exist.",
+            ),
+            (
+                DAG(dag_id="test"),
+                True,
+                {"external_task_group_id": [TEST_TASK_ID, TEST_TASK_ID_ALTERNATE]},
+                f"The external task group '{re.escape(str([TEST_TASK_ID, TEST_TASK_ID_ALTERNATE]))}'"
+                f" in DAG '{TEST_DAG_ID}' does not exist.",
+            ),
+        ),
+    )
+    @pytest.mark.parametrize(
+        "soft_fail, expected_exception",
+        (
+            (
+                False,
+                AirflowException,
+            ),
+            (
+                True,
+                AirflowSkipException,
+            ),
+        ),
+    )
+    @mock.patch("airflow.sensors.external_task.ExternalTaskSensor._get_dttm_filter")
+    @mock.patch("airflow.models.dagbag.DagBag.get_dag")
+    @mock.patch("os.path.exists")
+    @mock.patch("airflow.models.dag.DagModel.get_current")
+    def test_fail__check_for_existence(
+        self,
+        get_current,
+        exists,
+        get_dag,
+        _get_dttm_filter,
+        soft_fail,
+        expected_exception,
+        response_get_current,
+        response_exists,
+        kwargs,
+        expected_message,
+    ):
+        _get_dttm_filter.return_value = []
+        get_current.return_value = response_get_current
+        exists.return_value = response_exists
+        get_dag_response = mock.MagicMock()
+        get_dag.return_value = get_dag_response
+        get_dag_response.has_task.return_value = False
+        get_dag_response.has_task_group.return_value = False
+        op = ExternalTaskSensor(
+            task_id="test_external_task_duplicate_task_ids",
+            external_dag_id=TEST_DAG_ID,
+            allowed_states=["success"],
+            dag=self.dag,
+            soft_fail=soft_fail,
+            check_existence=True,
+            **kwargs,
+        )
+        expected_message = "Skipping due to soft_fail is set to True." if soft_fail else expected_message
+        with pytest.raises(expected_exception, match=expected_message):
+            op.execute(context={})
+
 
 class TestExternalTaskAsyncSensor:
     TASK_ID = "external_task_sensor_check"