[bin][findtests] use more appropriate flag

.gitlab-ci/default.yml

@@ -20,7 +20,7 @@ select tests:
     - |
       if [[ "$TRIGGER_SOURCE" == "merge_request_event" ]]; then
           python3 bin/testing/getchangedfiles.py -o changedfiles.txt -t origin/$MR_TARGET_BRANCH_NAME
-          python3 bin/testing/findtests.py -f affectedtests.json --file-list changedfiles.txt --build-dir build-cmake
+          python3 bin/testing/findtests.py -o affectedtests.json --file-list changedfiles.txt --build-dir build-cmake
       else
           echo "Skipping test selection, build/test stages will consider all tests!"
           echo "{}" >> ../affectedtests.json

bin/testing/findtests.py

@@ -86,7 +86,7 @@ if __name__ == '__main__':
     parser.add_argument('-np', '--num-processes',
                         required=False, type=int, default=4,
                         help='Number of processes (default: 4)')
-    parser.add_argument('-f', '--outfile',
+    parser.add_argument('-o', '--outfile',
                         required=False, default='affectedtests.json',
                         help='The file in which to write the affected tests')
     parser.add_argument('-b', '--build-dir',