diff --git a/.github/workflows/macos.yml b/.github/workflows/macos.yml
index 0bf2158a7e7..c0b214fc8f6 100644
--- a/.github/workflows/macos.yml
+++ b/.github/workflows/macos.yml
@@ -108,18 +108,30 @@ jobs:
             -ra . \
             -m 'needs_solo_run'
 
+      - name: Cache GRASS Sample Dataset
+        id: cached-data
+        uses: actions/cache@0c907a75c2c80ebcb7f088228285e798b750cf8f # v4.2.1
+        with:
+          path: sample-data/nc_spm_full_v2alpha2.tar.gz
+          key: nc_spm_full_v2alpha2.tar.gz
+          enableCrossOsArchive: true
+
+      - name: Download GRASS Sample Dataset
+        if: steps.cached-data.outputs.cache-hit != 'true'
+        run: |
+          mkdir -p sample-data
+          curl -L "$SAMPLE_DATA" -o sample-data/nc_spm_full_v2alpha2.tar.gz
+        env:
+          SAMPLE_DATA: "https://grass.osgeo.org/sampledata/north_carolina/\
+            nc_spm_full_v2alpha2.tar.gz"
+
       - name: Run gunittest tests
         shell: micromamba-shell {0}
-        run: |
-          grass --tmp-project XY --exec \
-              g.download.project url=${{ env.SampleData }} path=$HOME
-          grass --tmp-project XY --exec \
-              python3 -m grass.gunittest.main \
-              --grassdata $HOME --location nc_spm_full_v2alpha2 --location-type nc \
-              --min-success 100 --config .github/workflows/macos_gunittest.cfg
+        run: .github/workflows/test_thorough.sh --config .github/workflows/macos_gunittest.cfg
         env:
-          SampleData: "https://grass.osgeo.org/sampledata/north_carolina/\
+          SAMPLE_DATA_URL: "file://${{ github.workspace }}/sample-data/\
             nc_spm_full_v2alpha2.tar.gz"
+
       - name: Make HTML test report available
         if: ${{ !cancelled() }}
         uses: actions/upload-artifact@65c4c4a1ddee5b72f698fdd19549f0f0fb45cf08 # v4.6.0
diff --git a/.github/workflows/test_thorough.sh b/.github/workflows/test_thorough.sh
index 6ed7d22078a..57c545133df 100755
--- a/.github/workflows/test_thorough.sh
+++ b/.github/workflows/test_thorough.sh
@@ -3,8 +3,10 @@
 # fail on non-zero return code from a subprocess
 set -e
 
+SAMPLE_DATA_URL=${SAMPLE_DATA_URL:-"https://grass.osgeo.org/sampledata/north_carolina/nc_spm_full_v2alpha2.tar.gz"}
+
 grass --tmp-project XY --exec \
-    g.download.project url=https://grass.osgeo.org/sampledata/north_carolina/nc_spm_full_v2alpha2.tar.gz path=$HOME
+    g.download.project url=$SAMPLE_DATA_URL path=$HOME
 
 grass --tmp-project XY --exec \
     python3 -m grass.gunittest.main \
diff --git a/.github/workflows/ubuntu.yml b/.github/workflows/ubuntu.yml
index 5f130a00812..0260e8882e2 100644
--- a/.github/workflows/ubuntu.yml
+++ b/.github/workflows/ubuntu.yml
@@ -146,8 +146,28 @@ jobs:
       - name: Test executing of the grass command
         run: .github/workflows/test_simple.sh
 
+      - name: Cache GRASS Sample Dataset
+        id: cached-data
+        uses: actions/cache@0c907a75c2c80ebcb7f088228285e798b750cf8f # v4.2.1
+        with:
+          path: sample-data/nc_spm_full_v2alpha2.tar.gz
+          key: nc_spm_full_v2alpha2.tar.gz
+          enableCrossOsArchive: true
+
+      - name: Download GRASS Sample Dataset
+        if: steps.cached-data.outputs.cache-hit != 'true'
+        run: |
+          mkdir -p sample-data
+          curl -L "$SAMPLE_DATA" -o sample-data/nc_spm_full_v2alpha2.tar.gz
+        env:
+          SAMPLE_DATA: "https://grass.osgeo.org/sampledata/north_carolina/\
+            nc_spm_full_v2alpha2.tar.gz"
+
       - name: Run tests
         run: .github/workflows/test_thorough.sh --config .gunittest.extra.cfg
+        env:
+          SAMPLE_DATA_URL: "file://${{ github.workspace }}/sample-data/\
+            nc_spm_full_v2alpha2.tar.gz"
 
       - name: Make HTML test report available
         if: ${{ always() }}