From 91906049ad95fc10e0c7097a28ea76edf890a08f Mon Sep 17 00:00:00 2001
From: faouziH21 <2004homsani@gmail.com>
Date: Fri, 21 Aug 2026 15:41:50 +0200
Subject: [PATCH 01/24] feat: adds a workflow for testing advection example

---
 .github/workflows/test_t8code_advection.yml | 76 +++++++++++++++++++++
 1 file changed, 76 insertions(+)
 create mode 100644 .github/workflows/test_t8code_advection.yml

diff --git a/.github/workflows/test_t8code_advection.yml b/.github/workflows/test_t8code_advection.yml
new file mode 100644
index 0000000000..9c94ea4a6b
--- /dev/null
+++ b/.github/workflows/test_t8code_advection.yml
@@ -0,0 +1,76 @@
+name: test t8code examples
+
+
+#  This file is part of t8code.
+#  t8code is a C library to manage a collection (a forest) of multiple
+#  connected adaptive space-trees of general element types in parallel.
+#
+#  Copyright (C) 2026 the developers
+#
+#  t8code is free software; you can redistribute it and/or modify
+#  it under the terms of the GNU General Public License as published by
+#  the Free Software Foundation; either version 2 of the License, or
+#  (at your option) any later version.
+#
+#  t8code is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#  GNU General Public License for more details.
+#
+#  You should have received a copy of the GNU General Public License
+#  along with t8code; if not, write to the Free Software Foundation, Inc.,
+#  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+name: Test t8code Compilation
+
+on:
+  push:
+    branches: [ "main" ]
+  pull_request:
+    branches: [ "main" ]
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    strategy:
+      fail-fast: false
+      matrix:
+        compiler: [gcc, clang]
+        # Test various compiler flags and debug levels
+        flags:
+          - "-O2"
+          - "-O3 -Wall -Wextra"
+          - "-DT8_ENABLE_DEBUG=1"
+          - "-O2 -DT8_ENABLE_DEBUG=0"
+
+    steps:
+    - name: Checkout Code
+      uses: actions/checkout@v4
+
+    - name: Install System Dependencies
+      run: |
+        sudo apt-get update
+        sudo apt-get install -y \
+          cmake \
+          build-essential \
+          gfortran \
+          libopenmpi-dev \
+          openmpi-bin \
+          clang
+
+    - name: Configure CMake
+      run: |
+        if [ "${{ matrix.compiler }}" = "gcc" ]; then
+          export CC=gcc CXX=g++
+        else
+          export CC=clang CXX=clang++
+        fi
+
+        cmake -B build -S . \
+          -DCMAKE_BUILD_TYPE=Release \
+          -DEXTRA_FLAGS="${{ matrix.flags }}"
+
+    - name: Compile Executable
+      run: |
+        cmake --build build --target t8_advection -j $(nproc)
\ No newline at end of file

From 38b72b7effbc6f352c138c4ea75513262ce1c310 Mon Sep 17 00:00:00 2001
From: faouziH21 <2004homsani@gmail.com>
Date: Fri, 21 Aug 2026 15:45:32 +0200
Subject: [PATCH 02/24] fix: make name more specific

---
 .github/workflows/test_t8code_advection.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/test_t8code_advection.yml b/.github/workflows/test_t8code_advection.yml
index 9c94ea4a6b..5b9be1316e 100644
--- a/.github/workflows/test_t8code_advection.yml
+++ b/.github/workflows/test_t8code_advection.yml
@@ -1,4 +1,4 @@
-name: test t8code examples
+name: test t8code advection examples
 
 
 #  This file is part of t8code.

From cdfa61216cc68214cda3ab1fb682a7d4657e79ab Mon Sep 17 00:00:00 2001
From: faouziH21 <2004homsani@gmail.com>
Date: Fri, 21 Aug 2026 15:46:51 +0200
Subject: [PATCH 03/24] fix: remove second name

---
 .github/workflows/test_t8code_advection.yml | 1 -
 1 file changed, 1 deletion(-)

diff --git a/.github/workflows/test_t8code_advection.yml b/.github/workflows/test_t8code_advection.yml
index 5b9be1316e..6bd4a45581 100644
--- a/.github/workflows/test_t8code_advection.yml
+++ b/.github/workflows/test_t8code_advection.yml
@@ -20,7 +20,6 @@ name: test t8code advection examples
 #  You should have received a copy of the GNU General Public License
 #  along with t8code; if not, write to the Free Software Foundation, Inc.,
 #  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
-name: Test t8code Compilation
 
 on:
   push:

From a98285c1324d48c33dbe45d9a9bbfbf498b1335f Mon Sep 17 00:00:00 2001
From: faouziH21 <2004homsani@gmail.com>
Date: Fri, 21 Aug 2026 16:00:46 +0200
Subject: [PATCH 04/24] fix: rewrite configure cmake

---
 .github/workflows/test_t8code_advection.yml | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/.github/workflows/test_t8code_advection.yml b/.github/workflows/test_t8code_advection.yml
index 6bd4a45581..5c5347b37a 100644
--- a/.github/workflows/test_t8code_advection.yml
+++ b/.github/workflows/test_t8code_advection.yml
@@ -60,16 +60,18 @@ jobs:
 
     - name: Configure CMake
       run: |
+        # Set compiler variables based on matrix selection
         if [ "${{ matrix.compiler }}" = "gcc" ]; then
-          export CC=gcc CXX=g++
+          C_COMP="gcc"
+          CXX_COMP="g++"
         else
-          export CC=clang CXX=clang++
+          C_COMP="clang"
+          CXX_COMP="clang++"
         fi
 
         cmake -B build -S . \
+          -DCMAKE_C_COMPILER=$C_COMP \
+          -DCMAKE_CXX_COMPILER=$CXX_COMP \
           -DCMAKE_BUILD_TYPE=Release \
-          -DEXTRA_FLAGS="${{ matrix.flags }}"
-
-    - name: Compile Executable
-      run: |
-        cmake --build build --target t8_advection -j $(nproc)
\ No newline at end of file
+          -DCMAKE_C_FLAGS="${{ matrix.flags }}" \
+          -DCMAKE_CXX_FLAGS="${{ matrix.flags }}")
\ No newline at end of file

From a42b493b878472a8421a799f15ca88da83141b57 Mon Sep 17 00:00:00 2001
From: faouziH21 <2004homsani@gmail.com>
Date: Fri, 21 Aug 2026 16:06:13 +0200
Subject: [PATCH 05/24] fix: adds back the executable

---
 .github/workflows/test_t8code_advection.yml | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/test_t8code_advection.yml b/.github/workflows/test_t8code_advection.yml
index 5c5347b37a..c6ddfaa4ce 100644
--- a/.github/workflows/test_t8code_advection.yml
+++ b/.github/workflows/test_t8code_advection.yml
@@ -74,4 +74,9 @@ jobs:
           -DCMAKE_CXX_COMPILER=$CXX_COMP \
           -DCMAKE_BUILD_TYPE=Release \
           -DCMAKE_C_FLAGS="${{ matrix.flags }}" \
-          -DCMAKE_CXX_FLAGS="${{ matrix.flags }}")
\ No newline at end of file
+          -DCMAKE_CXX_FLAGS="${{ matrix.flags }}")
+
+    - name: Compile Executable
+      run: |
+        NPROC=$(nproc)
+        cmake --build build --target t8_advection -j $NPROC
\ No newline at end of file

From 57285008a86be8b6447c7210f00f35f02a386fe3 Mon Sep 17 00:00:00 2001
From: faouziH21 <2004homsani@gmail.com>
Date: Fri, 21 Aug 2026 16:10:41 +0200
Subject: [PATCH 06/24] fix: removes nproc and exchanges it with parallel

---
 .github/workflows/test_t8code_advection.yml | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/.github/workflows/test_t8code_advection.yml b/.github/workflows/test_t8code_advection.yml
index c6ddfaa4ce..caed22da88 100644
--- a/.github/workflows/test_t8code_advection.yml
+++ b/.github/workflows/test_t8code_advection.yml
@@ -76,7 +76,5 @@ jobs:
           -DCMAKE_C_FLAGS="${{ matrix.flags }}" \
           -DCMAKE_CXX_FLAGS="${{ matrix.flags }}")
 
-    - name: Compile Executable
-      run: |
-        NPROC=$(nproc)
-        cmake --build build --target t8_advection -j $NPROC
\ No newline at end of file
+   - name: Compile Executable
+      run: cmake --build build --target t8_advection --parallel
\ No newline at end of file

From 98cc07dbc09fdef2d17cd0148cf988ac62693cbf Mon Sep 17 00:00:00 2001
From: faouziH21 <2004homsani@gmail.com>
Date: Fri, 21 Aug 2026 16:14:47 +0200
Subject: [PATCH 07/24] lint: adds 1 space

---
 .github/workflows/test_t8code_advection.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/test_t8code_advection.yml b/.github/workflows/test_t8code_advection.yml
index caed22da88..2287476ce4 100644
--- a/.github/workflows/test_t8code_advection.yml
+++ b/.github/workflows/test_t8code_advection.yml
@@ -76,5 +76,5 @@ jobs:
           -DCMAKE_C_FLAGS="${{ matrix.flags }}" \
           -DCMAKE_CXX_FLAGS="${{ matrix.flags }}")
 
-   - name: Compile Executable
+    - name: Compile Executable
       run: cmake --build build --target t8_advection --parallel
\ No newline at end of file

From 8435ca3533291b96d4e7da1a30fb51ee85963d80 Mon Sep 17 00:00:00 2001
From: faouziH21 <2004homsani@gmail.com>
Date: Fri, 21 Aug 2026 16:17:49 +0200
Subject: [PATCH 08/24] fix: removes trailing )

---
 .github/workflows/test_t8code_advection.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/test_t8code_advection.yml b/.github/workflows/test_t8code_advection.yml
index 2287476ce4..bba4fc3406 100644
--- a/.github/workflows/test_t8code_advection.yml
+++ b/.github/workflows/test_t8code_advection.yml
@@ -74,7 +74,7 @@ jobs:
           -DCMAKE_CXX_COMPILER=$CXX_COMP \
           -DCMAKE_BUILD_TYPE=Release \
           -DCMAKE_C_FLAGS="${{ matrix.flags }}" \
-          -DCMAKE_CXX_FLAGS="${{ matrix.flags }}")
+          -DCMAKE_CXX_FLAGS="${{ matrix.flags }}"
 
     - name: Compile Executable
       run: cmake --build build --target t8_advection --parallel
\ No newline at end of file

From cd66ae9bcd3affccc3b8c5e623ed77b355b00642 Mon Sep 17 00:00:00 2001
From: faouziH21 <2004homsani@gmail.com>
Date: Fri, 21 Aug 2026 16:20:56 +0200
Subject: [PATCH 09/24] fix: set a fetch depth

---
 .github/workflows/test_t8code_advection.yml | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/.github/workflows/test_t8code_advection.yml b/.github/workflows/test_t8code_advection.yml
index bba4fc3406..29e1004656 100644
--- a/.github/workflows/test_t8code_advection.yml
+++ b/.github/workflows/test_t8code_advection.yml
@@ -46,6 +46,8 @@ jobs:
     steps:
     - name: Checkout Code
       uses: actions/checkout@v4
+      with:
+        fetch-depth: 0
 
     - name: Install System Dependencies
       run: |

From 9bf377f9bbf10ba16490331bb95bd8004554c003 Mon Sep 17 00:00:00 2001
From: faouziH21 <2004homsani@gmail.com>
Date: Fri, 21 Aug 2026 16:40:50 +0200
Subject: [PATCH 10/24] chore: replace gcc with mpi

---
 .github/workflows/test_t8code_advection.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/test_t8code_advection.yml b/.github/workflows/test_t8code_advection.yml
index 29e1004656..d2c939e754 100644
--- a/.github/workflows/test_t8code_advection.yml
+++ b/.github/workflows/test_t8code_advection.yml
@@ -64,8 +64,8 @@ jobs:
       run: |
         # Set compiler variables based on matrix selection
         if [ "${{ matrix.compiler }}" = "gcc" ]; then
-          C_COMP="gcc"
-          CXX_COMP="g++"
+          C_COMP="mpicc"
+          CXX_COMP="mpicxx"
         else
           C_COMP="clang"
           CXX_COMP="clang++"

From a91514b5ba8642008b44f2efa90e4da05fa840c4 Mon Sep 17 00:00:00 2001
From: faouziH21 <2004homsani@gmail.com>
Date: Mon, 31 Aug 2026 12:32:49 +0200
Subject: [PATCH 11/24] fix: improves the test and uses t8code docker container

---
 .github/workflows/test_t8code_advection.yml | 163 ++++++++++++++------
 1 file changed, 119 insertions(+), 44 deletions(-)

diff --git a/.github/workflows/test_t8code_advection.yml b/.github/workflows/test_t8code_advection.yml
index d2c939e754..310e63267c 100644
--- a/.github/workflows/test_t8code_advection.yml
+++ b/.github/workflows/test_t8code_advection.yml
@@ -21,62 +21,137 @@ name: test t8code advection examples
 #  along with t8code; if not, write to the Free Software Foundation, Inc.,
 #  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 
+env:
+  DEBUG_CONFIG: "-O1"
+
 on:
-  push:
-    branches: [ "main" ]
-  pull_request:
-    branches: [ "main" ]
-  workflow_dispatch:
+  workflow_call:
+    inputs:
+      MAKEFLAGS:
+        required: true
+        type: string
+        description: 'Make flags to use for compilation (like -j4)'
+      MPI:
+        required: true
+        type: string
+        description: 'Use MPI for compilation (ON/OFF)'
+      BUILD_TYPE:
+        required: true
+        type: string
+        description: 'Build type (Release/Debug)'
+      TEST_LEVEL:
+        required: true
+        type: string
+        description: 'Test level used for configuring'
+        default: 'T8_TEST_LEVEL_FULL'
 
 jobs:
-  build:
+  fine_grained_trigger:
+    runs-on: ubuntu-latest
+    outputs:
+      run_ci: ${{ steps.set_run_ci.outputs.RUN_CI }}
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          repository: ${{ github.event.pull_request.head.repo.full_name }}
+          ref: ${{ github.event.pull_request.head.ref }}
+          fetch-depth: 0
+      - name: set the run_ci variable for the testsuite
+        id: set_run_ci
+        run: |
+          if [[ "${{ github.event_name }}" == "schedule" && "${{ github.repository }}" == "DLR-AMR/t8code" ]]; then
+            echo "RUN_CI=true" >> $GITHUB_OUTPUT
+            exit 0
+          elif [[ "${{ github.event_name }}" == "merge_group" ]]; then
+            echo "RUN_CI=true" >> $GITHUB_OUTPUT
+            exit 0
+          fi
+          latest_commit_message=$(git log -1 --pretty=%B)
+          if [[ "${{ github.event_name }}" != "schedule" ]]; then
+            if [[ "${{ github.event.pull_request.draft }}" == "false" ]]; then
+              echo "RUN_CI=true" >> $GITHUB_OUTPUT
+              exit 0
+            elif [[ "${{ github.event.pull_request.draft }}" == "true" && "$latest_commit_message" == *"[run ci]"* ]]; then
+              echo "RUN_CI=true" >> $GITHUB_OUTPUT
+              exit 0
+            elif [[ "${{ github.event.pull_request.ready_for_review }}" == "true" ]]; then
+              echo "RUN_CI=true" >> $GITHUB_OUTPUT
+              exit 0
+            else
+              echo "RUN_CI=false" >> $GITHUB_OUTPUT
+              exit 0
+            fi
+          else
+            echo "RUN_CI=false" >> $GITHUB_OUTPUT
+            exit 0
+          fi
+
+  preparation:
+    needs: [fine_grained_trigger]
+    secrets: inherit
+    if: needs.fine_grained_trigger.outputs.run_ci == 'true'
+    uses: ./.github/workflows/test_preparation.yml
+    strategy:
+      fail-fast: false
+      matrix:
+        MPI: [OFF, ON]
+        include:
+          - MAKEFLAGS: -j4
+    with:
+      MAKEFLAGS: ${{ matrix.MAKEFLAGS }}
+      IGNORE_CACHE: false
+      CACHE_COUNTER: 9
+      MPI: ${{ matrix.MPI }}
+
+  t8code_cmake_tests:
+    needs: preparation
+    timeout-minutes: 25
     runs-on: ubuntu-latest
+    container: dlramr/t8code-dependencies:t8-dependencies-ubuntu-gcc
+    steps:
+      - name: Download artifacts
+        uses: actions/download-artifact@v4
+        with:
+          name: SC_P4EST_MPI_${{ inputs.MPI }}
+      - name: untar artifact
+        run: tar -xf artifact.tar && rm artifact.tar
+      - name: disable ownership checks
+        run: git config --global --add safe.directory '*'
+      - name: Get input vars
+        run: |
+          export MAKEFLAGS="${{ inputs.MAKEFLAGS }}"
+          export MPI="${{ inputs.MPI }}"
+          export BUILD_TYPE="${{ inputs.BUILD_TYPE }}"
+          export SC_PATH=$PWD/sc/build/$BUILD_TYPE
+          export P4EST_PATH=$PWD/p4est/build/$BUILD_TYPE
+          echo MAKEFLAGS="$MAKEFLAGS" >> $GITHUB_ENV
+          echo MPI="$MPI" >> $GITHUB_ENV
+          echo BUILD_TYPE="$BUILD_TYPE" >> $GITHUB_ENV
+          echo SC_PATH="$SC_PATH" >> $GITHUB_ENV
+          echo P4EST_PATH="$P4EST_PATH" >> $GITHUB_ENV
 
+  build_advection:
+    needs: preparation
+    runs-on: ubuntu-latest
+    container: dlramr/t8code-dependencies:t8-dependencies-ubuntu-gcc
     strategy:
       fail-fast: false
       matrix:
-        compiler: [gcc, clang]
-        # Test various compiler flags and debug levels
+        compiler: [gcc]
         flags:
           - "-O2"
           - "-O3 -Wall -Wextra"
           - "-DT8_ENABLE_DEBUG=1"
           - "-O2 -DT8_ENABLE_DEBUG=0"
-
     steps:
-    - name: Checkout Code
-      uses: actions/checkout@v4
-      with:
-        fetch-depth: 0
-
-    - name: Install System Dependencies
-      run: |
-        sudo apt-get update
-        sudo apt-get install -y \
-          cmake \
-          build-essential \
-          gfortran \
-          libopenmpi-dev \
-          openmpi-bin \
-          clang
-
-    - name: Configure CMake
-      run: |
-        # Set compiler variables based on matrix selection
-        if [ "${{ matrix.compiler }}" = "gcc" ]; then
-          C_COMP="mpicc"
-          CXX_COMP="mpicxx"
-        else
-          C_COMP="clang"
-          CXX_COMP="clang++"
-        fi
-
-        cmake -B build -S . \
-          -DCMAKE_C_COMPILER=$C_COMP \
-          -DCMAKE_CXX_COMPILER=$CXX_COMP \
-          -DCMAKE_BUILD_TYPE=Release \
-          -DCMAKE_C_FLAGS="${{ matrix.flags }}" \
-          -DCMAKE_CXX_FLAGS="${{ matrix.flags }}"
+      - name: Configure CMake
+        run: |
+          cmake -B build -S . \
+            -DCMAKE_C_COMPILER=mpicc \
+            -DCMAKE_CXX_COMPILER=mpiccxx \
+            -DCMAKE_BUILD_TYPE=Release \
+            -DCMAKE_C_FLAGS="${{ matrix.flags }}" \
+            -DCMAKE_CXX_FLAGS="${{ matrix.flags }}"
 
-    - name: Compile Executable
-      run: cmake --build build --target t8_advection --parallel
\ No newline at end of file
+      - name: Compile Executable
+        run: cmake --build build --target t8_advection --parallel
\ No newline at end of file

From b738c00c07370bf4fb5ee0d0522de138e098512b Mon Sep 17 00:00:00 2001
From: faouziH21 <2004homsani@gmail.com>
Date: Mon, 31 Aug 2026 12:44:17 +0200
Subject: [PATCH 12/24] [run ci]


From 1c673562001154079b2891a0ac3ca75bd961ec70 Mon Sep 17 00:00:00 2001
From: faouziH21 <2004homsani@gmail.com>
Date: Mon, 31 Aug 2026 14:18:22 +0200
Subject: [PATCH 13/24] integrates advection into the testsuite

---
 .github/workflows/test_t8code_advection.yml | 164 +++++++-------------
 .github/workflows/testsuite.yml             |  17 ++
 2 files changed, 77 insertions(+), 104 deletions(-)

diff --git a/.github/workflows/test_t8code_advection.yml b/.github/workflows/test_t8code_advection.yml
index 310e63267c..142b7e918b 100644
--- a/.github/workflows/test_t8code_advection.yml
+++ b/.github/workflows/test_t8code_advection.yml
@@ -27,7 +27,7 @@ env:
 on:
   workflow_call:
     inputs:
-      MAKEFLAGS:
+      MAKEFLAGS: #um aendern in run flags
         required: true
         type: string
         description: 'Make flags to use for compilation (like -j4)'
@@ -46,112 +46,68 @@ on:
         default: 'T8_TEST_LEVEL_FULL'
 
 jobs:
-  fine_grained_trigger:
-    runs-on: ubuntu-latest
-    outputs:
-      run_ci: ${{ steps.set_run_ci.outputs.RUN_CI }}
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          repository: ${{ github.event.pull_request.head.repo.full_name }}
-          ref: ${{ github.event.pull_request.head.ref }}
-          fetch-depth: 0
-      - name: set the run_ci variable for the testsuite
-        id: set_run_ci
-        run: |
-          if [[ "${{ github.event_name }}" == "schedule" && "${{ github.repository }}" == "DLR-AMR/t8code" ]]; then
-            echo "RUN_CI=true" >> $GITHUB_OUTPUT
-            exit 0
-          elif [[ "${{ github.event_name }}" == "merge_group" ]]; then
-            echo "RUN_CI=true" >> $GITHUB_OUTPUT
-            exit 0
-          fi
-          latest_commit_message=$(git log -1 --pretty=%B)
-          if [[ "${{ github.event_name }}" != "schedule" ]]; then
-            if [[ "${{ github.event.pull_request.draft }}" == "false" ]]; then
-              echo "RUN_CI=true" >> $GITHUB_OUTPUT
-              exit 0
-            elif [[ "${{ github.event.pull_request.draft }}" == "true" && "$latest_commit_message" == *"[run ci]"* ]]; then
-              echo "RUN_CI=true" >> $GITHUB_OUTPUT
-              exit 0
-            elif [[ "${{ github.event.pull_request.ready_for_review }}" == "true" ]]; then
-              echo "RUN_CI=true" >> $GITHUB_OUTPUT
-              exit 0
-            else
-              echo "RUN_CI=false" >> $GITHUB_OUTPUT
-              exit 0
-            fi
-          else
-            echo "RUN_CI=false" >> $GITHUB_OUTPUT
-            exit 0
-          fi
-
-  preparation:
-    needs: [fine_grained_trigger]
-    secrets: inherit
-    if: needs.fine_grained_trigger.outputs.run_ci == 'true'
-    uses: ./.github/workflows/test_preparation.yml
-    strategy:
-      fail-fast: false
-      matrix:
-        MPI: [OFF, ON]
-        include:
-          - MAKEFLAGS: -j4
-    with:
-      MAKEFLAGS: ${{ matrix.MAKEFLAGS }}
-      IGNORE_CACHE: false
-      CACHE_COUNTER: 9
-      MPI: ${{ matrix.MPI }}
-
-  t8code_cmake_tests:
-    needs: preparation
+  t8code_advection_test:
     timeout-minutes: 25
     runs-on: ubuntu-latest
     container: dlramr/t8code-dependencies:t8-dependencies-ubuntu-gcc
     steps:
-      - name: Download artifacts
-        uses: actions/download-artifact@v4
-        with:
-          name: SC_P4EST_MPI_${{ inputs.MPI }}
-      - name: untar artifact
-        run: tar -xf artifact.tar && rm artifact.tar
-      - name: disable ownership checks
-        run: git config --global --add safe.directory '*'
-      - name: Get input vars
-        run: |
-          export MAKEFLAGS="${{ inputs.MAKEFLAGS }}"
-          export MPI="${{ inputs.MPI }}"
-          export BUILD_TYPE="${{ inputs.BUILD_TYPE }}"
-          export SC_PATH=$PWD/sc/build/$BUILD_TYPE
-          export P4EST_PATH=$PWD/p4est/build/$BUILD_TYPE
-          echo MAKEFLAGS="$MAKEFLAGS" >> $GITHUB_ENV
-          echo MPI="$MPI" >> $GITHUB_ENV
-          echo BUILD_TYPE="$BUILD_TYPE" >> $GITHUB_ENV
-          echo SC_PATH="$SC_PATH" >> $GITHUB_ENV
-          echo P4EST_PATH="$P4EST_PATH" >> $GITHUB_ENV
+#
+# Setup
+#
+    - name: Download artifacts
+      uses: actions/download-artifact@v8
+      with:
+        name: SC_P4EST_MPI_${{ inputs.MPI }}
+    - name: untar artifact
+      run: tar -xf artifact.tar && rm artifact.tar
+      # This seems to be necessary because of the docker container
+    - name: disable ownership checks
+      run: git config --global --add safe.directory '*'
+    - name: Get input vars
+      run: export MAKEFLAGS="${{ inputs.MAKEFLAGS }}"
+        && export MPI="${{ inputs.MPI }}"
+        && export BUILD_TYPE="${{ inputs.BUILD_TYPE }}"
+        && export SC_PATH=$PWD/sc/build/$BUILD_TYPE
+        && export P4EST_PATH=$PWD/p4est/build/$BUILD_TYPE
+        && echo MAKEFLAGS="$MAKEFLAGS" >> $GITHUB_ENV
+        && echo MPI="$MPI" >> $GITHUB_ENV
+        && echo BUILD_TYPE="$BUILD_TYPE" >> $GITHUB_ENV
+        && echo SC_PATH="$SC_PATH" >> $GITHUB_ENV
+        && echo P4EST_PATH="$P4EST_PATH" >> $GITHUB_ENV
 
-  build_advection:
-    needs: preparation
-    runs-on: ubuntu-latest
-    container: dlramr/t8code-dependencies:t8-dependencies-ubuntu-gcc
-    strategy:
-      fail-fast: false
-      matrix:
-        compiler: [gcc]
-        flags:
-          - "-O2"
-          - "-O3 -Wall -Wextra"
-          - "-DT8_ENABLE_DEBUG=1"
-          - "-O2 -DT8_ENABLE_DEBUG=0"
-    steps:
-      - name: Configure CMake
-        run: |
-          cmake -B build -S . \
-            -DCMAKE_C_COMPILER=mpicc \
-            -DCMAKE_CXX_COMPILER=mpiccxx \
-            -DCMAKE_BUILD_TYPE=Release \
-            -DCMAKE_C_FLAGS="${{ matrix.flags }}" \
-            -DCMAKE_CXX_FLAGS="${{ matrix.flags }}"
+#
+#  T8CODE
+#
+#
+    # build config vars
+      run: cd build && ninja install $MAKEFLAGS
+    - name: Set test level
+      run: export TEST_LEVEL_FLAG="-DT8CODE_TEST_LEVEL=${{ inputs.TEST_LEVEL }}"
+           && echo TEST_LEVEL_FLAG="$TEST_LEVEL_FLAG" >> $GITHUB_ENV
+    - name: build config variables
+      run: export CONFIG_OPTIONS="${TEST_LEVEL_FLAG} -GNinja -DCMAKE_C_FLAGS_DEBUG=${DEBUG_CONFIG} -DCMAKE_CXX_FLAGS_DEBUG=${DEBUG_CONFIG} -DT8CODE_BUILD_MESH_HANDLE=ON -DT8CODE_USE_SYSTEM_SC=ON -DT8CODE_USE_SYSTEM_P4EST=ON -DT8CODE_BUILD_PEDANTIC=ON -DT8CODE_BUILD_WALL=ON -DT8CODE_BUILD_WERROR=ON -DT8CODE_BUILD_WEXTRA=ON -DT8CODE_ENABLE_MPI=$MPI -DCMAKE_BUILD_TYPE=$BUILD_TYPE -DSC_DIR=$SC_PATH/install/cmake -DP4EST_DIR=$P4EST_PATH/install/cmake"
+           && echo CONFIG_OPTIONS="$CONFIG_OPTIONS" >> $GITHUB_ENV
+    # cmake and test with api options
+    - name: echo cmake line
+      run: echo cmake ../ $CONFIG_OPTIONS
+    - name: cmake
+      run: mkdir build && cd build && cmake ../ $CONFIG_OPTIONS
+    - name: OnFailUploadLog
+      if: failure()
+      uses: actions/upload-artifact@v7
+      with:
+        name: cmake_${{ inputs.BUILD_TYPE }}_MPI_${{ inputs.MPI }}_api.log
+        path: build/CMakeFiles/CMakeOutput.log
+    - name: ninja
+      run: cd build && ninja $MAKEFLAGS
+    - name: ninja install
+      run: cd build && ninja install $MAKEFLAGS
+    - name: OnFailUploadLog
+      if: failure()
+      uses: actions/upload-artifact@v7
+      with:
+        name: test-suite_${{ inputs.BUILD_TYPE }}_MPI_${{ inputs.MPI }}_api.log
+        path: build/Testing/Temporary/LastTest.log
+    - name: run advection test 1D Mesh
+      run: ./t8_advection -u 1 -e 1 -l 2 -r 1 -T 0.5 -C 0.5 -a 1 -v 1
 
-      - name: Compile Executable
-        run: cmake --build build --target t8_advection --parallel
\ No newline at end of file
diff --git a/.github/workflows/testsuite.yml b/.github/workflows/testsuite.yml
index 92c72c8853..fe951e3909 100644
--- a/.github/workflows/testsuite.yml
+++ b/.github/workflows/testsuite.yml
@@ -188,6 +188,23 @@ jobs:
       BUILD_TYPE: ${{ matrix.BUILD_TYPE }}
       TEST_LEVEL: ${{ github.event_name == 'pull_request' && 'T8_TEST_LEVEL_MEDIUM' || 'T8_TEST_LEVEL_FULL' }} # Set TEST_LEVEL to medium if the event is a PR, otherwise full.
 
+  t8code_advection_test:
+    needs: preparation
+    uses: ./.github/workflows/test_t8code_advection.yml
+    strategy:
+      fail-fast: false
+      matrix:
+        MPI: [ON] # For now the fortran API only supports building with MPI
+        BUILD_TYPE: [Debug, Release]
+        include:
+          - MAKEFLAGS: -j4
+    with:
+      MAKEFLAGS: ${{ matrix.MAKEFLAGS }}
+      MPI: ${{ matrix.MPI }}
+      BUILD_TYPE: ${{ matrix.BUILD_TYPE }}
+      TEST_LEVEL: ${{ github.event_name == 'pull_request' && 'T8_TEST_LEVEL_MEDIUM' || 'T8_TEST_LEVEL_FULL' }} # Set TEST_LEVEL to medium if the event is a PR, otherwise full.
+
+
   # Run Valgrind check for every t8code test binary.
   t8code_valgrind_tests:
     if: (github.event_name == 'schedule' && github.repository == 'DLR-AMR/t8code') # Only run the Valgrind check in the scheduled run.

From e7592241b37285eef66a08e53b0a4b66712ee5cf Mon Sep 17 00:00:00 2001
From: faouziH21 <2004homsani@gmail.com>
Date: Mon, 31 Aug 2026 14:18:54 +0200
Subject: [PATCH 14/24] [run ci]


From 4fcdaf17926751b49c39892428373d2d1d152637 Mon Sep 17 00:00:00 2001
From: faouziH21 <2004homsani@gmail.com>
Date: Mon, 31 Aug 2026 14:31:04 +0200
Subject: [PATCH 15/24] fix: fixes orphaned run and path error

---
 .github/workflows/test_t8code_advection.yml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/test_t8code_advection.yml b/.github/workflows/test_t8code_advection.yml
index 142b7e918b..d7bfd4ed27 100644
--- a/.github/workflows/test_t8code_advection.yml
+++ b/.github/workflows/test_t8code_advection.yml
@@ -80,6 +80,7 @@ jobs:
 #
 #
     # build config vars
+   - name: ninja install
       run: cd build && ninja install $MAKEFLAGS
     - name: Set test level
       run: export TEST_LEVEL_FLAG="-DT8CODE_TEST_LEVEL=${{ inputs.TEST_LEVEL }}"
@@ -109,5 +110,5 @@ jobs:
         name: test-suite_${{ inputs.BUILD_TYPE }}_MPI_${{ inputs.MPI }}_api.log
         path: build/Testing/Temporary/LastTest.log
     - name: run advection test 1D Mesh
-      run: ./t8_advection -u 1 -e 1 -l 2 -r 1 -T 0.5 -C 0.5 -a 1 -v 1
+      run: : cd build/example/advection && ./t8_advection -u 1 -e 1 -l 2 -r 1 -T 0.5 -C 0.5 -a 1 -v 1
 

From 764a06d1e7414424f8e5f82196c47656bc912ddf Mon Sep 17 00:00:00 2001
From: faouziH21 <2004homsani@gmail.com>
Date: Mon, 31 Aug 2026 14:34:29 +0200
Subject: [PATCH 16/24] fix: removes trailing ;

---
 .github/workflows/test_t8code_advection.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/test_t8code_advection.yml b/.github/workflows/test_t8code_advection.yml
index d7bfd4ed27..3a5729a4f0 100644
--- a/.github/workflows/test_t8code_advection.yml
+++ b/.github/workflows/test_t8code_advection.yml
@@ -110,5 +110,5 @@ jobs:
         name: test-suite_${{ inputs.BUILD_TYPE }}_MPI_${{ inputs.MPI }}_api.log
         path: build/Testing/Temporary/LastTest.log
     - name: run advection test 1D Mesh
-      run: : cd build/example/advection && ./t8_advection -u 1 -e 1 -l 2 -r 1 -T 0.5 -C 0.5 -a 1 -v 1
+      run: cd build/example/advection && ./t8_advection -u 1 -e 1 -l 2 -r 1 -T 0.5 -C 0.5 -a 1 -v 1
 

From 2c6eaa4e4cbd91eb947f7cb85daf0c8f70715c09 Mon Sep 17 00:00:00 2001
From: faouziH21 <2004homsani@gmail.com>
Date: Mon, 31 Aug 2026 14:50:24 +0200
Subject: [PATCH 17/24] fix: simplifies run command and removes a copy paste
 mistake

---
 .github/workflows/test_t8code_advection.yml | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/.github/workflows/test_t8code_advection.yml b/.github/workflows/test_t8code_advection.yml
index 3a5729a4f0..df47f82ae7 100644
--- a/.github/workflows/test_t8code_advection.yml
+++ b/.github/workflows/test_t8code_advection.yml
@@ -80,8 +80,6 @@ jobs:
 #
 #
     # build config vars
-   - name: ninja install
-      run: cd build && ninja install $MAKEFLAGS
     - name: Set test level
       run: export TEST_LEVEL_FLAG="-DT8CODE_TEST_LEVEL=${{ inputs.TEST_LEVEL }}"
            && echo TEST_LEVEL_FLAG="$TEST_LEVEL_FLAG" >> $GITHUB_ENV
@@ -109,6 +107,7 @@ jobs:
       with:
         name: test-suite_${{ inputs.BUILD_TYPE }}_MPI_${{ inputs.MPI }}_api.log
         path: build/Testing/Temporary/LastTest.log
-    - name: run advection test 1D Mesh
-      run: cd build/example/advection && ./t8_advection -u 1 -e 1 -l 2 -r 1 -T 0.5 -C 0.5 -a 1 -v 1
 
+    - name: run advection test 1D Mesh
+          working-directory: build/example/advection
+          run: ./t8_advection -u 1 -e 1 -l 2 -r 1 -T 0.5 -C 0.5 -a 1 -v 1

From 2e511771c044e35bc2a6c279924a105f6e6ec1ab Mon Sep 17 00:00:00 2001
From: faouziH21 <2004homsani@gmail.com>
Date: Mon, 31 Aug 2026 14:52:12 +0200
Subject: [PATCH 18/24] lint: fixes spacing

---
 .github/workflows/test_t8code_advection.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/test_t8code_advection.yml b/.github/workflows/test_t8code_advection.yml
index df47f82ae7..69b0898a07 100644
--- a/.github/workflows/test_t8code_advection.yml
+++ b/.github/workflows/test_t8code_advection.yml
@@ -109,5 +109,5 @@ jobs:
         path: build/Testing/Temporary/LastTest.log
 
     - name: run advection test 1D Mesh
-          working-directory: build/example/advection
-          run: ./t8_advection -u 1 -e 1 -l 2 -r 1 -T 0.5 -C 0.5 -a 1 -v 1
+        working-directory: build/example/advection
+        run: ./t8_advection -u 1 -e 1 -l 2 -r 1 -T 0.5 -C 0.5 -a 1 -v 1

From 804d47b04937667264bca791c1e91bd9d2db9e1c Mon Sep 17 00:00:00 2001
From: faouziH21 <2004homsani@gmail.com>
Date: Mon, 31 Aug 2026 14:54:24 +0200
Subject: [PATCH 19/24] lint: fixes spacing

---
 .github/workflows/test_t8code_advection.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/test_t8code_advection.yml b/.github/workflows/test_t8code_advection.yml
index 69b0898a07..d3d2c54811 100644
--- a/.github/workflows/test_t8code_advection.yml
+++ b/.github/workflows/test_t8code_advection.yml
@@ -109,5 +109,5 @@ jobs:
         path: build/Testing/Temporary/LastTest.log
 
     - name: run advection test 1D Mesh
-        working-directory: build/example/advection
-        run: ./t8_advection -u 1 -e 1 -l 2 -r 1 -T 0.5 -C 0.5 -a 1 -v 1
+      working-directory: build/example/advection
+      run: ./t8_advection -u 1 -e 1 -l 2 -r 1 -T 0.5 -C 0.5 -a 1 -v 1

From fbec48d7eedb249fba9e244c0f0702a04c42ffac Mon Sep 17 00:00:00 2001
From: faouziH21 <2004homsani@gmail.com>
Date: Mon, 31 Aug 2026 14:55:49 +0200
Subject: [PATCH 20/24] [run ci]


From 6d15d9d9e9a18e95a7599cac10720b70b6ca68dc Mon Sep 17 00:00:00 2001
From: faouziH21 <2004homsani@gmail.com>
Date: Mon, 31 Aug 2026 16:09:54 +0200
Subject: [PATCH 21/24] feat: adds more tests and a MPI flag

---
 .github/workflows/test_t8code_advection.yml | 18 +++++++++++++++---
 .github/workflows/testsuite.yml             |  4 +++-
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/.github/workflows/test_t8code_advection.yml b/.github/workflows/test_t8code_advection.yml
index d3d2c54811..2502209968 100644
--- a/.github/workflows/test_t8code_advection.yml
+++ b/.github/workflows/test_t8code_advection.yml
@@ -27,10 +27,14 @@ env:
 on:
   workflow_call:
     inputs:
-      MAKEFLAGS: #um aendern in run flags
+      MAKEFLAGS:
         required: true
         type: string
         description: 'Make flags to use for compilation (like -j4)'
+      MPIFLAGS:
+        required: true
+        type: string
+        description: 'Flags passed to mpirun when executing tests (like -np 4)'
       MPI:
         required: true
         type: string
@@ -65,11 +69,13 @@ jobs:
       run: git config --global --add safe.directory '*'
     - name: Get input vars
       run: export MAKEFLAGS="${{ inputs.MAKEFLAGS }}"
+        && export MPIFLAGS="${{ inputs.MPIFLAGS }}"
         && export MPI="${{ inputs.MPI }}"
         && export BUILD_TYPE="${{ inputs.BUILD_TYPE }}"
         && export SC_PATH=$PWD/sc/build/$BUILD_TYPE
         && export P4EST_PATH=$PWD/p4est/build/$BUILD_TYPE
         && echo MAKEFLAGS="$MAKEFLAGS" >> $GITHUB_ENV
+        && echo MPIFLAGS="$MPIFLAGS" >> $GITHUB_ENV
         && echo MPI="$MPI" >> $GITHUB_ENV
         && echo BUILD_TYPE="$BUILD_TYPE" >> $GITHUB_ENV
         && echo SC_PATH="$SC_PATH" >> $GITHUB_ENV
@@ -109,5 +115,11 @@ jobs:
         path: build/Testing/Temporary/LastTest.log
 
     - name: run advection test 1D Mesh
-      working-directory: build/example/advection
-      run: ./t8_advection -u 1 -e 1 -l 2 -r 1 -T 0.5 -C 0.5 -a 1 -v 1
+      working-directory: build/example/advect
+      run: mpirun $MPIFLAGS ./t8_advection -u 1 -e 1 -l 2 -r 1 -T 0.5 -C 0.5 -a 1 -v 1
+    - name: run advection test 1D Mesh
+      working-directory: build/example/advect
+      run: mpirun $MPIFLAGS ./t8_advection -u 2 -e 7 -l 2 -r 1 -T 0.5 -C 0.5 -a 1 -v 1
+    - name: run advection test 3D Mesh
+      working-directory: build/example/advect
+      run: mpirun $MPIFLAGS ./t8_advection -u 3 -e 7 -l 2 -r 1 -T 0.5 -C 0.5 -a 1 -v 1
diff --git a/.github/workflows/testsuite.yml b/.github/workflows/testsuite.yml
index fe951e3909..868785f89c 100644
--- a/.github/workflows/testsuite.yml
+++ b/.github/workflows/testsuite.yml
@@ -195,11 +195,13 @@ jobs:
       fail-fast: false
       matrix:
         MPI: [ON] # For now the fortran API only supports building with MPI
-        BUILD_TYPE: [Debug, Release]
+        BUILD_TYPE: [Release]
         include:
           - MAKEFLAGS: -j4
+            MPIFLAGS: -np 4
     with:
       MAKEFLAGS: ${{ matrix.MAKEFLAGS }}
+      MPIFLAGS: ${{ matrix.MPIFLAGS }}
       MPI: ${{ matrix.MPI }}
       BUILD_TYPE: ${{ matrix.BUILD_TYPE }}
       TEST_LEVEL: ${{ github.event_name == 'pull_request' && 'T8_TEST_LEVEL_MEDIUM' || 'T8_TEST_LEVEL_FULL' }} # Set TEST_LEVEL to medium if the event is a PR, otherwise full.

From b5f2ff626e435b3549ed8eb2405bb6d7c78e63bc Mon Sep 17 00:00:00 2001
From: faouziH21 <2004homsani@gmail.com>
Date: Mon, 31 Aug 2026 16:13:35 +0200
Subject: [PATCH 22/24] [run ci]


From b6a56a39c742dbe0d4fa8fe975f5d13fb905d1df Mon Sep 17 00:00:00 2001
From: faouziH21 <2004homsani@gmail.com>
Date: Wed, 2 Sep 2026 17:38:31 +0200
Subject: [PATCH 23/24] fix: removes vtk writing and changes a couple of flags

---
 .github/workflows/test_t8code_advection.yml | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/.github/workflows/test_t8code_advection.yml b/.github/workflows/test_t8code_advection.yml
index 2502209968..0a38678980 100644
--- a/.github/workflows/test_t8code_advection.yml
+++ b/.github/workflows/test_t8code_advection.yml
@@ -114,12 +114,12 @@ jobs:
         name: test-suite_${{ inputs.BUILD_TYPE }}_MPI_${{ inputs.MPI }}_api.log
         path: build/Testing/Temporary/LastTest.log
 
-    - name: run advection test 1D Mesh
+    - name: run advection test 1D Mesh Constant 1 in x-direction
       working-directory: build/example/advect
-      run: mpirun $MPIFLAGS ./t8_advection -u 1 -e 1 -l 2 -r 1 -T 0.5 -C 0.5 -a 1 -v 1
-    - name: run advection test 1D Mesh
+      run: mpirun $MPIFLAGS ./t8_advection -u 1 -e 1 -l 2 -r 1 -T 0.5 -C 0.5 -a 1 -o
+    - name: run advection test 2D Mesh Constant 1 in x,y, and z.
       working-directory: build/example/advect
-      run: mpirun $MPIFLAGS ./t8_advection -u 2 -e 7 -l 2 -r 1 -T 0.5 -C 0.5 -a 1 -v 1
-    - name: run advection test 3D Mesh
+      run: mpirun $MPIFLAGS ./t8_advection -u 2 -e 7 -l 2 -r 1 -T 0.5 -C 0.5 -a 1 -o
+    - name: run advection test 3D Mesh with turbulent flow
       working-directory: build/example/advect
-      run: mpirun $MPIFLAGS ./t8_advection -u 3 -e 7 -l 2 -r 1 -T 0.5 -C 0.5 -a 1 -v 1
+      run: mpirun $MPIFLAGS ./t8_advection -u 3 -e 8 -l 2 -r 1 -T 0.5 -C 0.5 -a 1 -o

From c279cdfe9d6e7ba5e18ff2a333ff4b759281c941 Mon Sep 17 00:00:00 2001
From: faouziH21 <2004homsani@gmail.com>
Date: Wed, 2 Sep 2026 17:41:19 +0200
Subject: [PATCH 24/24] [run ci]