ci: use system-wide coverage/pytest-cov

tox.ini

@@ -50,7 +50,17 @@ pass_env =
     ANSYS_DPF_PATH
 
 deps = 
-    -r requirements/requirements_test.txt
+    ; -r requirements/requirements_test.txt
+    ansys-platform-instancemanagement==1.1.2
+    ; coverage==7.6.10
+    imageio==2.36.0
+    imageio-ffmpeg==0.5.1
+    pytest==8.3.4
+    ; pytest-cov==6.0.0
+    pytest-order==1.3.0
+    pytest-rerunfailures==15.0
+    pyvista==0.44.2
+    vtk==9.3.1
 
 [testenv:build-wheel]
 description = Environment for custom build of package wheels
@@ -120,9 +130,10 @@ depends = pretest
 
 setenv =
     # Pytest extra arguments
-    COVERAGE = --cov=ansys.dpf.core --log-level=ERROR --cov-append #--cov-report=xml --cov-report=html 
+    COVERAGE = --cov=ansys.dpf.core --cov-report=xml --cov-report=html --log-level=ERROR --cov-append
     RERUNS = --reruns=2 --reruns-delay=1
     DEBUG = -v -s --durations=10 --durations-min=1.0
+    VIRTUALENV_SYSTEM_SITE_PACKAGES = true
 
     api: JUNITXML = --junitxml=tests/junit/test-results.xml
     launcher: JUNITXML = --junitxml=tests/junit/test-results2.xml
@@ -155,7 +166,6 @@ setenv =
     TMP = {env_tmp_dir}
 
 commands =
-    coverage --version
     python -m pytest {env:PYTEST_PYTHON_FILES} {env:DEBUG} {env:RERUNS} {env:JUNITXML} {env:COVERAGE} {posargs}
 
 [testenv:doc-{clean,links,html}]