diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index abd4dc35..be5fc189 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -141,6 +141,16 @@ jobs:
         with:
           path: "site/"
 
+  test-devcontainer:
+    # https://github.com/devcontainers/ci/
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Build and run dev container task
+        uses: devcontainers/ci@v0.3
+        with:
+          runCmd: ./test.bash
+
   deploy-website:
     needs: build
     if: ${{ github.event_name == 'push' }}
diff --git a/tools/asdf/install.bash b/tools/asdf/install.bash
index 7925b9ed..0d82a03b 100755
--- a/tools/asdf/install.bash
+++ b/tools/asdf/install.bash
@@ -21,8 +21,9 @@ set -euo pipefail
 # comes with several Java versions pre-installed by SDKMAN already,
 # let's wipe everything, and (re)install only the one we want below
 # (via ASDF, for consistency), to avoid confusion:
+# (NB: sudo is required under devcontainers/ci.)
 # TODO Remove this when .devcontainer/devcontainer.json switched to a ligher base image
-rm -rf /usr/local/sdkman/candidates/java/
+sudo rm -rf /usr/local/sdkman/candidates/java/
 
 if ! [ -x "$(command -v asdf)" ]; then
   if ! [ -d "$HOME/.asdf/" ]; then