diff --git a/.github/workflows/build-slides.yml b/.github/workflows/build-slides.yml
index 9885049..0534103 100644
--- a/.github/workflows/build-slides.yml
+++ b/.github/workflows/build-slides.yml
@@ -3,7 +3,15 @@ name: Build LaTeX Slides
 on: [push, pull_request]
 
 jobs:
+  test_slides_change:
+    runs-on: ubuntu-latest
+    uses: tj-actions/verify-changed-files@v6.2
+    with:
+      files: |
+        packaging/slides/*
+        testing/slides/*
   build-slides:
+    if: steps.verify-changed-files.outputs.files_changed == 'true'
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
diff --git a/.github/workflows/conda-skhep.yml b/.github/workflows/conda-skhep.yml
index e52f0b7..e30a4f4 100644
--- a/.github/workflows/conda-skhep.yml
+++ b/.github/workflows/conda-skhep.yml
@@ -4,7 +4,14 @@ on: [push, pull_request]
 
 
 jobs:
+  test_env_change:
+    runs-on: ubuntu-latest
+    uses: tj-actions/verify-changed-files@v6.2
+    with:
+      files: |
+        scikit-hep/environment.yml
   build:
+    if: steps.verify-changed-files.outputs.files_changed == 'true'
     runs-on: ${{ matrix.os }}
     strategy:
       max-parallel: 5
diff --git a/.github/workflows/gh_pages.yml b/.github/workflows/gh_pages.yml
index 4fec8a2..62ddc37 100644
--- a/.github/workflows/gh_pages.yml
+++ b/.github/workflows/gh_pages.yml
@@ -6,7 +6,14 @@ on:
       - main  # Set a branch to deploy
 
 jobs:
+  test_pages_change:
+    runs-on: ubuntu-latest
+    uses: tj-actions/verify-changed-files@v6.2
+    with:
+      files: |
+        docs/*
   deploy:
+    if: steps.verify-changed-files.outputs.files_changed == 'true'
     runs-on: ubuntu-18.04
     steps:
       - uses: actions/checkout@v2
@@ -26,8 +33,6 @@ jobs:
           echo "$PWD";
           ls;
 
-
-
       - name: Deploy
         uses: peaceiris/actions-gh-pages@v3
         with:
diff --git a/.github/workflows/python-package-conda.yml b/.github/workflows/python-package-conda.yml
index fe40259..178cf89 100644
--- a/.github/workflows/python-package-conda.yml
+++ b/.github/workflows/python-package-conda.yml
@@ -4,7 +4,20 @@ on: [push, pull_request]
 
 
 jobs:
+  test_env_change:
+    runs-on: ubuntu-latest
+    outputs:
+      env: ${{ steps.file-changes.outputs.env }}
+    steps:
+    - uses: dorny/paths-filter@v2
+      id: file-changes
+      with:
+        filters: |
+          env:
+            - environment.yml
   build:
+    needs: test_env_changes
+    if: ${{ needs.test_env_changes.outputs.env == 'true' }}
     runs-on: ${{ matrix.os }}
     strategy:
       max-parallel: 5
@@ -15,10 +28,6 @@ jobs:
     - uses: actions/checkout@v2
       with:
         submodules: recursive
-    - uses: tj-actions/verify-changed-files@v6.2
-      with:
-        files: |
-          environment.yml
     - uses: conda-incubator/setup-miniconda@v2
       with:
         auto-update-conda: true
@@ -31,7 +40,6 @@ jobs:
         conda info
 
     - name: Install dependencies
-      if: steps.verify-changed-files.outputs.files_changed == 'true'
       shell: bash -leo pipefail {0}
       run: |
         conda install mamba -n base -c conda-forge
diff --git a/docs/content/posts/welcome.md b/docs/content/posts/welcome.md
index 34ec0ed..24f406b 100644
--- a/docs/content/posts/welcome.md
+++ b/docs/content/posts/welcome.md
@@ -98,10 +98,8 @@ https://indico.in2p3.fr/event/20306/contributions/95829/
     </embed>
 </object>
 
-
 ## Recorded lecture
 
-
 <iframe width="100%" height="500" src="https://www.youtube.com/embed/TUrJ_IudVx8" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
 
 
diff --git a/environment.yml b/environment.yml
index bed3c38..515ee14 100644
--- a/environment.yml
+++ b/environment.yml
@@ -30,3 +30,6 @@ dependencies:
   - wheel
   - pip:
     - build
+    - pytest
+
+