diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index e9703d30bfa..5b3d4e1c5b1 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -175,11 +175,20 @@ jobs:
           ./sage -python -m pytest -c tox.ini -qq --doctest --collect-only || true
         shell: sh .ci/docker-exec-script.sh BUILD /sage {0}
 
+      - name: Get changed files
+        id: changed-files
+        uses: tj-actions/changed-files@v44
+        with:
+          files: src/**/*.{py,pyx,pxd,pxi,sage,spyx,rst,tex}
+          files_ignore: src/{setup,conftest*}.py
+
       - name: Test changed files (sage -t --new)
+        if: steps.changed-files.outputs.all_changed_files
         run: |
           export MAKE="make -j2 --output-sync=recurse" SAGE_NUM_THREADS=4
           # We run tests with "sage -t --new"; this only tests the uncommitted changes.
-          ./sage -t --new -p4
+          # https://github.com/tj-actions/changed-files?tab=readme-ov-file#outputs-
+          ./sage -t --long --format github -p4 ${{ steps.changed-files.outputs.all_changed_files }}
         shell: sh .ci/docker-exec-script.sh BUILD /sage {0}
 
   test-mod: