diff --git a/.travis.yml b/.travis.yml
index 58a8450b8..3ec8a2b65 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,6 +8,16 @@ addons:
       - gnupg2
 matrix:
   include:
+    - name: source-test
+      script:
+        - |
+          set -e
+          ./tools/prepare-source.sh
+          if [ ! $(git diff --quiet --exit-code) ]; then
+            echo
+            echo "Please include these changes in your branch: "
+            git diff
+          fi
     - name: unit-tests
       arch: amd64
       language: go
diff --git a/tools/prepare-source.sh b/tools/prepare-source.sh
new file mode 100755
index 000000000..f77218b57
--- /dev/null
+++ b/tools/prepare-source.sh
@@ -0,0 +1,7 @@
+#!/bin/sh
+
+set -eux
+
+go fmt ./...
+go mod tidy
+go mod vendor