support/testing: test_ddrescue.py: use assertRunNotOk()

Use the helper to simplify the test.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
(cherry picked from commit d7284778a1)
Signed-off-by: Thomas Perale <thomas.perale@mind.be>

support/testing/tests/package/test_ddrescue.py

@@ -70,8 +70,7 @@ class TestDdrescue(infra.basetest.BRTest):
 
         # A normal 'dd' is expected to fail with I/O error
         cmd = f"dd if={dm_dev} of=/dev/null bs=512"
-        _, exit_code = self.emulator.run(cmd)
-        self.assertNotEqual(exit_code, 0)
+        self.assertRunNotOk(cmd)
 
         # Where a normal 'dd' fails, 'ddrescue' is expected to succeed
         self.assertRunOk(f"ddrescue {dm_dev} {ddrescue_img}")