diff --git a/.github/workflows/main.yaml b/.github/workflows/main.yaml
index 60463cd..8f66d3c 100644
--- a/.github/workflows/main.yaml
+++ b/.github/workflows/main.yaml
@@ -17,29 +17,47 @@ jobs:
     steps:
       - uses: actions/checkout@v2
 
+      
       - name: Get number of CPU cores
         uses: SimenB/github-actions-cpu-cores@v1
-
+      
+      - name: apt-install
+        run: |
+          sudo apt-get update -y && sudo apt-get install -y  \
+            libwoff1  libvpx9  libevent-2.1-7t64 libopus0 libgstreamer-plugins-base1.0-0 \
+            libgstreamer-gl1.0-0 \
+            libgstreamer-plugins-bad1.0-0 \
+            libflite1 \
+            libavif16 \
+            libharfbuzz-icu0 \
+            libsecret-1-0 \
+            libhyphen0 \
+            libmanette-0.2-0 \
+            libgles2 \
+            gstreamer1.0-libav
+      
       - name: Install mamba
-        uses: mamba-org/provision-with-micromamba@main
+        uses: mamba-org/setup-micromamba@v2
         with:
           environment-file: dev-env.yml
           environment-name: dev-env
-          micromamba-version: "1.4.1"
-
+          init-shell: >-
+            bash     
+          
       - name: Install Playwright
+        shell: bash -el {0}
         run: |
           playwright install
 
       - name: Install pyjs-code-runner
+        shell: bash -el {0}
         run: |
-          micromamba activate dev-env
           python -m pip install . --no-deps
 
       - name: Run Tests
+        shell: bash -el {0}
         run: |
-          micromamba activate dev-env
-          pytest -s
+          pytest -s -vvvvv 
 
 
   test_with_pip:
@@ -50,20 +68,34 @@ jobs:
       - name: Get number of CPU cores
         uses: SimenB/github-actions-cpu-cores@v1
 
+      - name: apt-install
+        run: |
+          sudo apt-get update -y && sudo apt-get install -y  \
+            libwoff1  libvpx9  libevent-2.1-7t64 libopus0 libgstreamer-plugins-base1.0-0 \
+            libgstreamer-gl1.0-0 \
+            libgstreamer-plugins-bad1.0-0 \
+            libflite1 \
+            libavif16 \
+            libharfbuzz-icu0 \
+            libsecret-1-0 \
+            libhyphen0 \
+            libmanette-0.2-0 \
+            libgles2 \
+            gstreamer1.0-libav
+
       - name: Install mamba
-        uses: mamba-org/provision-with-micromamba@main
+        uses: mamba-org/setup-micromamba@v2
         with:
           environment-file: dev-env-pip.yml
           environment-name: dev-env
-          micromamba-version: "1.4.1"
 
       - name: Install pyjs-code-runner
+        shell: bash -el {0}
         run: |
-          micromamba activate dev-env
           python -m pip install .
           playwright install
-
+          
       - name: Run Tests
+        shell: bash -el {0}
         run: |
-          micromamba activate dev-env
-          pytest -s
+          pytest -s -vvvvv 
diff --git a/dev-env-pip.yml b/dev-env-pip.yml
index 5a9a416..657a9bd 100644
--- a/dev-env-pip.yml
+++ b/dev-env-pip.yml
@@ -4,5 +4,9 @@ channels:
 dependencies:
   - python
   - pip
-  - emsdk
-  - pytest
\ No newline at end of file
+  - pytest
+  - pytest-sugar
+  - typer
+  - appdirs
+  - empack >=3,<4
+  - rich
diff --git a/dev-env.yml b/dev-env.yml
index 5fc1183..97104d2 100644
--- a/dev-env.yml
+++ b/dev-env.yml
@@ -5,9 +5,10 @@ dependencies:
   - python
   - pip
   - pytest
+  - pytest-sugar
   - typer
   - appdirs
   - empack >=3,<4
   - microsoft::playwright
   - emsdk
-  - rich
\ No newline at end of file
+  - rich
diff --git a/pyjs_code_runner/js/utils.js b/pyjs_code_runner/js/utils.js
index ccb558d..b5ecdf7 100644
--- a/pyjs_code_runner/js/utils.js
+++ b/pyjs_code_runner/js/utils.js
@@ -39,7 +39,13 @@ function eval_main_script(pyjs, workdir, filename) {
         return 0;
     }
     catch (e) {
-        console.error("error while evaluating main file:", e)
+        if (typeof e === "number") {
+            const msg = get_exception_message(e);
+            console.error("error while evaluating main file:", msg)
+        }
+        else {
+            console.error("error while evaluating main file:", e)
+        }
         return 1;
     }
     return 0
diff --git a/test/conftest.py b/test/conftest.py
index 2062967..5a6d201 100644
--- a/test/conftest.py
+++ b/test/conftest.py
@@ -6,30 +6,25 @@
 from typer.testing import CliRunner
 import os
 
-# @pytest.fixture(scope="session")
-# def session_temp_path(tmp_path_factory):
-#     return tmp_path_factory.mktemp()
-
 ON_GITHUB_ACTIONS = False
 if "GITHUB_ACTION" in os.environ:
     ON_GITHUB_ACTIONS = True
 
 
 @pytest.fixture(scope="session")
-def env_prefix():
-    env_root = Path(appdirs.user_data_dir("pytest_code_runner_tests", "DerThorsten"))
-    env_root.mkdir(exist_ok=True, parents=True)
+def env_prefix(tmp_path_factory):
+
+    env_root = tmp_path_factory.mktemp("pytest_code_runner_tests")
     env_prefix = Path(env_root) / "testenv"
 
     if env_prefix.exists():
         shutil.rmtree(env_prefix)
 
-    print("prefix", env_prefix)
     channels = (
         "-c https://repo.mamba.pm/emscripten-forge -c https://repo.mamba.pm/conda-forge"
     )
     cmd = [
-        f"""$MAMBA_EXE create {channels} --yes --prefix {env_prefix} --platform=emscripten-32   python numpy pyjs """
+        f"""$MAMBA_EXE create {channels} --yes --prefix {env_prefix} --platform=emscripten-32   python numpy pyjs>=2.7.0"""
     ]
 
     ret = subprocess.run(cmd, shell=True)
diff --git a/test/test_cli.py b/test/test_cli.py
index 44b0381..1d8fb08 100644
--- a/test/test_cli.py
+++ b/test/test_cli.py
@@ -20,6 +20,7 @@ def test_help(self, runner):
     def test_sync_err(
         self, env_prefix, em_work_dir, backend_cli_settings, tmpdir, runner
     ):
+
         backend_type, backend_args = backend_cli_settings
 
         to_mount_dir = tmpdir