diff --git a/.azure-pipelines/azure-pipelines-base.yml b/.azure-pipelines/azure-pipelines-base.yml
index b7a2ba1ed9..888801a3a7 100644
--- a/.azure-pipelines/azure-pipelines-base.yml
+++ b/.azure-pipelines/azure-pipelines-base.yml
@@ -5,8 +5,6 @@ jobs:
   variables:
     - name: NUMBA_DISABLE_JIT
       value: 1
-    - name: ARVIZ_CI_MACHINE
-      value: 1
   timeoutInMinutes: 360
   strategy:
     matrix:
@@ -82,9 +80,15 @@ jobs:
       python -m pip freeze
     displayName: 'Print packages'
 
+  - script: |
+      ARVIZ_REQUIRE_ALL_DEPS=TRUE python -m pytest arviz/tests/base_tests --cov arviz --cov-report=xml
+    condition: and(succeeded(), eq(variables.OptionalRequirements, true))
+    displayName: 'pytest (require all dependencies)'
+
   - script: |
       python -m pytest arviz/tests/base_tests --cov arviz --cov-report=xml
-    displayName: 'pytest'
+    condition: and(succeeded(), eq(variables.OptionalRequirements, false))
+    displayName: 'pytest (skip if dependency missing)'
 
   - script: |
       ls -ahl
diff --git a/.azure-pipelines/azure-pipelines-external.yml b/.azure-pipelines/azure-pipelines-external.yml
index b255ee8898..138ff80223 100644
--- a/.azure-pipelines/azure-pipelines-external.yml
+++ b/.azure-pipelines/azure-pipelines-external.yml
@@ -5,7 +5,7 @@ jobs:
   variables:
     - name: NUMBA_DISABLE_JIT
       value: 1
-    - name: ARVIZ_CI_MACHINE
+    - name: ARVIZ_REQUIRE_ALL_DEPS
       value: 1
   timeoutInMinutes: 360
   strategy:
diff --git a/arviz/tests/base_tests/test_data.py b/arviz/tests/base_tests/test_data.py
index bb1882059e..55882b81aa 100644
--- a/arviz/tests/base_tests/test_data.py
+++ b/arviz/tests/base_tests/test_data.py
@@ -42,7 +42,6 @@
     draws,
     eight_schools_params,
     models,
-    running_on_ci,
 )
 
 
@@ -1469,7 +1468,7 @@ def test_json_converters(self, models):
 
 
 @pytest.mark.skipif(
-    not (importlib.util.find_spec("datatree") or running_on_ci()),
+    not (importlib.util.find_spec("datatree") or "ARVIZ_REQUIRE_ALL_DEPS" in os.environ),
     reason="test requires xarray-datatree library",
 )
 class TestDataTree:
diff --git a/arviz/tests/base_tests/test_data_zarr.py b/arviz/tests/base_tests/test_data_zarr.py
index 53144ad3d8..c93b0253dd 100644
--- a/arviz/tests/base_tests/test_data_zarr.py
+++ b/arviz/tests/base_tests/test_data_zarr.py
@@ -16,7 +16,6 @@
     draws,
     eight_schools_params,
     importorskip,
-    running_on_ci,
 )
 
 zarr = importorskip("zarr")  # pylint: disable=invalid-name
diff --git a/arviz/tests/base_tests/test_diagnostics_numba.py b/arviz/tests/base_tests/test_diagnostics_numba.py
index e3da38ded5..5de10f716d 100644
--- a/arviz/tests/base_tests/test_diagnostics_numba.py
+++ b/arviz/tests/base_tests/test_diagnostics_numba.py
@@ -1,7 +1,4 @@
 """Test Diagnostic methods"""
-
-import importlib
-
 # pylint: disable=redefined-outer-name, no-member, too-many-public-methods
 import numpy as np
 import pytest
@@ -11,13 +8,10 @@
 from ...stats import bfmi, mcse, rhat
 from ...stats.diagnostics import _mc_error, ks_summary
 from ...utils import Numba
-from ..helpers import running_on_ci
+from ..helpers import importorskip
 from .test_diagnostics import data  # pylint: disable=unused-import
 
-pytestmark = pytest.mark.skipif(  # pylint: disable=invalid-name
-    (importlib.util.find_spec("numba") is None) and not running_on_ci(),
-    reason="test requires numba which is not installed",
-)
+importorskip("numba")
 
 rcParams["data.load"] = "eager"
 
diff --git a/arviz/tests/base_tests/test_plot_utils.py b/arviz/tests/base_tests/test_plot_utils.py
index 55d0224f3b..471bd91f27 100644
--- a/arviz/tests/base_tests/test_plot_utils.py
+++ b/arviz/tests/base_tests/test_plot_utils.py
@@ -1,5 +1,6 @@
 # pylint: disable=redefined-outer-name
 import importlib
+import os
 
 import numpy as np
 import pytest
@@ -20,10 +21,10 @@
 from ...sel_utils import xarray_sel_iter, xarray_to_ndarray
 from ...stats.density_utils import get_bins
 from ...utils import get_coords
-from ..helpers import running_on_ci
 
 # Check if Bokeh is installed
 bokeh_installed = importlib.util.find_spec("bokeh") is not None  # pylint: disable=invalid-name
+skip_tests = (not bokeh_installed) and ("ARVIZ_REQUIRE_ALL_DEPS" not in os.environ)
 
 
 @pytest.mark.parametrize(
@@ -212,10 +213,7 @@ def test_filter_plotter_list_warning():
     assert len(plotters_filtered) == 5
 
 
-@pytest.mark.skipif(
-    not (bokeh_installed or running_on_ci()),
-    reason="test requires bokeh which is not installed",
-)
+@pytest.mark.skipif(skip_tests, reason="test requires bokeh which is not installed")
 def test_bokeh_import():
     """Tests that correct method is returned on bokeh import"""
     plot = get_plotting_function("plot_dist", "distplot", "bokeh")
@@ -290,10 +288,7 @@ def test_mpl_dealiase_sel_kwargs():
     assert res["line_color"] == "red"
 
 
-@pytest.mark.skipif(
-    not (bokeh_installed or running_on_ci()),
-    reason="test requires bokeh which is not installed",
-)
+@pytest.mark.skipif(skip_tests, reason="test requires bokeh which is not installed")
 def test_bokeh_dealiase_sel_kwargs():
     """Check bokeh dealiase_sel_kwargs behaviour.
 
@@ -315,10 +310,7 @@ def test_bokeh_dealiase_sel_kwargs():
     assert res["line_color"] == "red"
 
 
-@pytest.mark.skipif(
-    not (bokeh_installed or running_on_ci()),
-    reason="test requires bokeh which is not installed",
-)
+@pytest.mark.skipif(skip_tests, reason="test requires bokeh which is not installed")
 def test_set_bokeh_circular_ticks_labels():
     """Assert the axes returned after placing ticks and tick labels for circular plots."""
     import bokeh.plotting as bkp
diff --git a/arviz/tests/base_tests/test_stats_numba.py b/arviz/tests/base_tests/test_stats_numba.py
index d6d63f3fc8..8b76bde113 100644
--- a/arviz/tests/base_tests/test_stats_numba.py
+++ b/arviz/tests/base_tests/test_stats_numba.py
@@ -1,6 +1,4 @@
 # pylint: disable=redefined-outer-name, no-member
-import importlib
-
 import numpy as np
 import pytest
 
@@ -9,15 +7,12 @@
 from ...utils import Numba
 from ..helpers import (  # pylint: disable=unused-import
     check_multiple_attrs,
+    importorskip,
     multidim_models,
-    running_on_ci,
 )
 from .test_stats import centered_eight, non_centered_eight  # pylint: disable=unused-import
 
-pytestmark = pytest.mark.skipif(  # pylint: disable=invalid-name
-    (importlib.util.find_spec("numba") is None) and not running_on_ci(),
-    reason="test requires numba which is not installed",
-)
+numba = importorskip("numba")
 
 rcParams["data.load"] = "eager"
 
diff --git a/arviz/tests/base_tests/test_utils_numba.py b/arviz/tests/base_tests/test_utils_numba.py
index c3d1f252ed..7a64944bfd 100644
--- a/arviz/tests/base_tests/test_utils_numba.py
+++ b/arviz/tests/base_tests/test_utils_numba.py
@@ -8,14 +8,10 @@
 
 from ...stats.stats_utils import stats_variance_2d as svar
 from ...utils import Numba, _numba_var, numba_check
-from ..helpers import running_on_ci
+from ..helpers import importorskip
 from .test_utils import utils_with_numba_import_fail  # pylint: disable=unused-import
 
-pytestmark = pytest.mark.skipif(  # pylint: disable=invalid-name
-    (importlib.util.find_spec("numba") is None) and not running_on_ci(),
-    reason="test requires numba which is not installed",
-)
-
+importorskip("numba")
 
 def test_utils_fixture(utils_with_numba_import_fail):
     """Test of utils fixture to ensure mock is applied correctly"""
diff --git a/arviz/tests/external_tests/test_data_pystan.py b/arviz/tests/external_tests/test_data_pystan.py
index 2be52c8fd4..42dca1fe1b 100644
--- a/arviz/tests/external_tests/test_data_pystan.py
+++ b/arviz/tests/external_tests/test_data_pystan.py
@@ -1,6 +1,7 @@
 # pylint: disable=no-member, invalid-name, redefined-outer-name, too-many-function-args
 import importlib
 from collections import OrderedDict
+import os
 
 import numpy as np
 import pytest
@@ -16,19 +17,18 @@
     importorskip,
     load_cached_models,
     pystan_version,
-    running_on_ci,
 )
 
 # Check if either pystan or pystan3 is installed
 pystan_installed = (importlib.util.find_spec("pystan") is not None) or (
     importlib.util.find_spec("stan") is not None
 )
-pytestmark = pytest.mark.skipif(
-    not (pystan_installed | running_on_ci()),
-    reason="test requires pystan/pystan3 which is not installed",
-)
 
 
+@pytest.mark.skipif(
+    not (pystan_installed or "ARVIZ_REQUIRE_ALL_DEPS" in os.environ),
+    reason="test requires pystan/pystan3 which is not installed"
+)
 class TestDataPyStan:
     @pytest.fixture(scope="class")
     def data(self, eight_schools_params, draws, chains):
diff --git a/arviz/tests/helpers.py b/arviz/tests/helpers.py
index 15dbd95689..3e826b8587 100644
--- a/arviz/tests/helpers.py
+++ b/arviz/tests/helpers.py
@@ -620,11 +620,6 @@ def test_precompile_models(eight_schools_params, draws, chains):
     load_cached_models(eight_schools_params, draws, chains)
 
 
-def running_on_ci() -> bool:
-    """Return True if running on CI machine."""
-    return os.environ.get("ARVIZ_CI_MACHINE") is not None
-
-
 def importorskip(
     modname: str, minversion: Optional[str] = None, reason: Optional[str] = None
 ) -> Any:
@@ -643,9 +638,9 @@ def importorskip(
     Example::
         docutils = pytest.importorskip("docutils")
     """
-    # ARVIZ_CI_MACHINE is True if tests run on CI, where ARVIZ_CI_MACHINE env variable exists
-    ARVIZ_CI_MACHINE = running_on_ci()
-    if not ARVIZ_CI_MACHINE:
+    # Unless ARVIZ_REQUIRE_ALL_DEPS is defined, tests that require a missing dependency are skipped
+    # if set, missing optional dependencies trigger failed tests.
+    if "ARVIZ_REQUIRE_ALL_DEPS" not in os.environ:
         return pytest.importorskip(modname=modname, minversion=minversion, reason=reason)
     import warnings