improve debug failing warning test (#18271)

Co-authored-by: Carlos Mocholí <[email protected]>
(cherry picked from commit 3ac550f)

Author: 2 people

tests/tests_fabric/utilities/test_warnings.py

@@ -40,16 +40,19 @@
         cache.deprecation("test7")
 
     output = stderr.getvalue()
-    assert "test_warnings.py:30: UserWarning: test1" in output
-    assert "test_warnings.py:31: DeprecationWarning: test2" in output
-
-    assert "test_warnings.py:33: UserWarning: test3" in output
-    assert "test_warnings.py:34: DeprecationWarning: test4" in output
-
-    assert "test_warnings.py:36: LightningDeprecationWarning: test5" in output
-
-    assert "test_warnings.py:39: UserWarning: test6" in output
-    assert "test_warnings.py:40: LightningDeprecationWarning: test7" in output
+    base_line = 30
+    expected_lines = [
+        f"test_warnings.py:{base_line}: UserWarning: test1",
+        f"test_warnings.py:{base_line+1}: DeprecationWarning: test2",
+        f"test_warnings.py:{base_line+3}: UserWarning: test3",
+        f"test_warnings.py:{base_line+4}: DeprecationWarning: test4",
+        f"test_warnings.py:{base_line+6}: LightningDeprecationWarning: test5",
+        f"test_warnings.py:{base_line+9}: UserWarning: test6",
+        f"test_warnings.py:{base_line+10}: LightningDeprecationWarning: test7",
+    ]
+
+    for ln in expected_lines:
+        assert ln in output, f"Missing line {ln!r} in:\n{output}"
 
     # check that logging is properly configured
     import logging