diff --git a/.github/workflows/pr.yml b/.github/workflows/pr.yml
index 2eb5663..8650aa7 100644
--- a/.github/workflows/pr.yml
+++ b/.github/workflows/pr.yml
@@ -20,6 +20,8 @@ jobs:
         run: |
           docker build -t $DOCKERHUB_URL:$TAG -f Dockerfile-$TAG .
           docker image ls
+          docker run -d $DOCKERHUB_URL:$TAG
+          docker ps -a
   ubuntu-14_04:
     runs-on: ubuntu-latest
     steps:
@@ -33,6 +35,8 @@ jobs:
         run: |
           docker build -t $DOCKERHUB_URL:$TAG -f Dockerfile-$TAG .
           docker image ls
+          docker run -d $DOCKERHUB_URL:$TAG
+          docker ps -a
   ubuntu-16_04:
     runs-on: ubuntu-latest
     steps:
@@ -46,6 +50,8 @@ jobs:
         run: |
           docker build -t $DOCKERHUB_URL:$TAG -f Dockerfile-$TAG .
           docker image ls
+          docker run -d $DOCKERHUB_URL:$TAG
+          docker ps -a
   ubuntu-18_04:
     runs-on: ubuntu-latest
     steps:
@@ -59,6 +65,8 @@ jobs:
         run: |
           docker build -t $DOCKERHUB_URL:$TAG -f Dockerfile-$TAG .
           docker image ls
+          docker run -d $DOCKERHUB_URL:$TAG
+          docker ps -a
   ubuntu-20_04:
     runs-on: ubuntu-latest
     steps:
@@ -72,6 +80,8 @@ jobs:
         run: |
           docker build -t $DOCKERHUB_URL:$TAG -f Dockerfile-$TAG .
           docker image ls
+          docker run -d $DOCKERHUB_URL:$TAG
+          docker ps -a
   ubuntu-22_04:
     runs-on: ubuntu-latest
     steps:
@@ -85,3 +95,5 @@ jobs:
         run: |
           docker build -t $DOCKERHUB_URL:$TAG -f Dockerfile-$TAG .
           docker image ls
+          docker run -d $DOCKERHUB_URL:$TAG
+          docker ps -a
diff --git a/Dockerfile-ubuntu-20.04 b/Dockerfile-ubuntu-20.04
index 8c7fdc2..39c9c14 100644
--- a/Dockerfile-ubuntu-20.04
+++ b/Dockerfile-ubuntu-20.04
@@ -30,4 +30,4 @@ STOPSIGNAL SIGRTMIN+3
 
 VOLUME [ "/sys/fs/cgroup" ]
 
-ENTRYPOINT ["/sbin/init"]
+ENTRYPOINT ["/bin/bash"]
diff --git a/Dockerfile-ubuntu-22.04 b/Dockerfile-ubuntu-22.04
index 3e0bc8c..1502cc0 100644
--- a/Dockerfile-ubuntu-22.04
+++ b/Dockerfile-ubuntu-22.04
@@ -30,4 +30,4 @@ STOPSIGNAL SIGRTMIN+3
 
 VOLUME [ "/sys/fs/cgroup" ]
 
-ENTRYPOINT ["/sbin/init"]
+ENTRYPOINT ["/bin/bash"]