diff --git a/.drone.yml b/.drone.yml
index cf4c358a..354cff95 100644
--- a/.drone.yml
+++ b/.drone.yml
@@ -24,6 +24,8 @@ clone:
 steps:
 - name: build
   image: alpine:3.13
+    environment:
+      TEST_CONTAINER: true
   pull: always
   commands:
     - scripts/run-full-tests
diff --git a/scripts/run-full-tests b/scripts/run-full-tests
index cbd824ce..bf26c212 100755
--- a/scripts/run-full-tests
+++ b/scripts/run-full-tests
@@ -8,7 +8,14 @@
 # For more information, see:
 # https://torsion.org/borgmatic/docs/how-to/develop-on-borgmatic/
 
-set -ex
+set -e
+
+if [ -z "$TEST_CONTAINER" ] ; then
+    echo "This script is designed to work inside a test container and is not intended to"
+    echo "be run manually. If you're trying to run borgmatic's end-to-end tests, execute"
+    echo "scripts/run-end-to-end-dev-tests instead."
+    exit 1
+fi
 
 apk add --no-cache python3 py3-pip borgbackup postgresql-client mariadb-client mongodb-tools \
     py3-ruamel.yaml py3-ruamel.yaml.clib bash sqlite
diff --git a/tests/end-to-end/docker-compose.yaml b/tests/end-to-end/docker-compose.yaml
index 090cf12c..884edba0 100644
--- a/tests/end-to-end/docker-compose.yaml
+++ b/tests/end-to-end/docker-compose.yaml
@@ -17,6 +17,8 @@ services:
       MONGO_INITDB_ROOT_PASSWORD: test
   tests:
     image: alpine:3.13
+    environment:
+      TEST_CONTAINER: true
     volumes:
       - "../..:/app:ro"
     tmpfs: