diff --git a/.github/workflows/continuous-integration.yml b/.github/workflows/continuous-integration.yml
index 492237b0..f7c0e402 100644
--- a/.github/workflows/continuous-integration.yml
+++ b/.github/workflows/continuous-integration.yml
@@ -1,5 +1,8 @@
 name: Tests
-on: [push, pull_request]
+on:
+  push:
+  pull_request:
+    types: [opened, synchronize, reopened, edited]
 jobs:
     ubuntu_test:
         name: Ubuntu tests
@@ -30,14 +33,15 @@ jobs:
 
                   if [ -n "${{ github.base_ref }}" ]; then
                     CHANGED_OUTPUTS=$(echo "${{ github.event.pull_request.body }}" | sed -n 's/.*CHANGED_OUTPUTS=\([^ ]*\).*/\1/p')
-                    BASE_BRANCH="${{ github.base_ref }}"
-                    HEAD_BRANCH="${{ github.head_ref || github.ref_name }}"
+                    BASE_REF="${{ github.base_ref }}"
+                    HEAD_REF=$(git rev-parse HEAD)
+                    echo "CHANGED_OUTPUTS: $CHANGED_OUTPUTS"
 
-                    git fetch origin $BASE_BRANCH
-                    git checkout $BASE_BRANCH
+                    git fetch origin $BASE_REF
+                    git checkout $BASE_REF
                     ./cargo_util.py --make_golden_outputs
-                    git checkout $HEAD_BRANCH
-                    ./cargo_util.py --test_outputs --ignore_new_outputs --changed_outputs $CHANGED_OUTPUTS
+                    git checkout $HEAD_REF
+                    ./cargo_util.py --test_outputs --ignore_new_outputs --changed_outputs=$CHANGED_OUTPUTS
                   fi
             - name: Upload golden outputs
               if: ${{ always() }}