Fix sftp sensor with pattern (#29467)

* Solve file_pattern issue with file path creation

This solves #28121

* Correct file_by_pattern.return_value in test

The output of SFTPHook.get_file_by_pattern is a file name and not the
full path to the file.

* Remove test_file_with_pattern_parameter_call

To my understanding, the goal of `test_file_with_pattern_parameter_call`
is to test whether we can call the function with the `file_pattern`
parameter.
Due to the previous changes, the `os.path.join` requires to set a value
for `sftp_hook_mock.return_value.get_file_by_pattern.return_value` so that the
`poke` function would run.

The case where we set this value is dealt with
`test_file_present_with_pattern` and
`test_file_not_present_with_pattern`.
`test_file_with_pattern_parameter_call` thus does not test anything
different or more specific than the two other tests.

---------

Co-authored-by: b.ramsauer@swiss-sdi.ch <b.ramsauer@swiss-sdi.ch>

airflow/providers/sftp/sensors/sftp.py

@@ -18,6 +18,7 @@
 """This module contains SFTP sensor."""
 from __future__ import annotations
 
+import os
 from datetime import datetime
 from typing import TYPE_CHECKING, Sequence
 
@@ -69,7 +70,7 @@ def poke(self, context: Context) -> bool:
         if self.file_pattern:
             file_from_pattern = self.hook.get_file_by_pattern(self.path, self.file_pattern)
             if file_from_pattern:
-                actual_file_to_check = file_from_pattern
+                actual_file_to_check = os.path.join(self.path, file_from_pattern)
             else:
                 return False
         else:

tests/providers/sftp/sensors/test_sftp.py

@@ -98,19 +98,10 @@ def test_naive_datetime(self, sftp_hook_mock):
         sftp_hook_mock.return_value.get_mod_time.assert_called_once_with("/path/to/file/1970-01-01.txt")
         assert not output
 
-    @patch("airflow.providers.sftp.sensors.sftp.SFTPHook")
-    def test_file_with_pattern_parameter_call(self, sftp_hook_mock):
-        sftp_hook_mock.return_value.get_mod_time.return_value = "19700101000000"
-        sftp_sensor = SFTPSensor(task_id="unit_test", path="/path/to/file/", file_pattern="*.txt")
-        context = {"ds": "1970-01-01"}
-        output = sftp_sensor.poke(context)
-        sftp_hook_mock.return_value.get_file_by_pattern.assert_called_once_with("/path/to/file/", "*.txt")
-        assert output
-
     @patch("airflow.providers.sftp.sensors.sftp.SFTPHook")
     def test_file_present_with_pattern(self, sftp_hook_mock):
         sftp_hook_mock.return_value.get_mod_time.return_value = "19700101000000"
-        sftp_hook_mock.return_value.get_file_by_pattern.return_value = "/path/to/file/text_file.txt"
+        sftp_hook_mock.return_value.get_file_by_pattern.return_value = "text_file.txt"
         sftp_sensor = SFTPSensor(task_id="unit_test", path="/path/to/file/", file_pattern="*.txt")
         context = {"ds": "1970-01-01"}
         output = sftp_sensor.poke(context)