diff --git a/meanas/test/conftest.py b/meanas/test/conftest.py
index 932a62c..311aae3 100644
--- a/meanas/test/conftest.py
+++ b/meanas/test/conftest.py
@@ -3,34 +3,38 @@
 Test fixtures
 
 """
-from typing import Tuple, Iterable, List
+from typing import Tuple, Iterable, List, Any
 import numpy        # type: ignore
 import pytest       # type: ignore
 
 from .utils import PRNG
 
+
+FixtureRequest = Any
+
+
 @pytest.fixture(scope='module',
                 params=[(5, 5, 1),
                         (5, 1, 5),
                         (5, 5, 5),
                         # (7, 7, 7),
                        ])
-def shape(request: pytest.FixtureRequest) -> Iterable[Tuple[int, ...]]:
+def shape(request: FixtureRequest) -> Iterable[Tuple[int, ...]]:
     yield (3, *request.param)
 
 
 @pytest.fixture(scope='module', params=[1.0, 1.5])
-def epsilon_bg(request: pytest.FixtureRequest) -> Iterable[float]:
+def epsilon_bg(request: FixtureRequest) -> Iterable[float]:
     yield request.param
 
 
 @pytest.fixture(scope='module', params=[1.0, 2.5])
-def epsilon_fg(request: pytest.FixtureRequest) -> Iterable[float]:
+def epsilon_fg(request: FixtureRequest) -> Iterable[float]:
     yield request.param
 
 
 @pytest.fixture(scope='module', params=['center', '000', 'random'])
-def epsilon(request: pytest.FixtureRequest,
+def epsilon(request: FixtureRequest,
             shape: Tuple[int, ...],
             epsilon_bg: float,
             epsilon_fg: float,
@@ -58,17 +62,17 @@ def epsilon(request: pytest.FixtureRequest,
 
 
 @pytest.fixture(scope='module', params=[1.0])  # 1.5
-def j_mag(request: pytest.FixtureRequest) -> Iterable[float]:
+def j_mag(request: FixtureRequest) -> Iterable[float]:
     yield request.param
 
 
 @pytest.fixture(scope='module', params=[1.0, 1.5])
-def dx(request: pytest.FixtureRequest) -> Iterable[float]:
+def dx(request: FixtureRequest) -> Iterable[float]:
     yield request.param
 
 
 @pytest.fixture(scope='module', params=['uniform', 'centerbig'])
-def dxes(request: pytest.FixtureRequest,
+def dxes(request: FixtureRequest,
          shape: Tuple[int, ...],
          dx: float,
          ) -> Iterable[List[List[numpy.ndarray]]]:
diff --git a/meanas/test/test_fdfd.py b/meanas/test/test_fdfd.py
index ac84213..076cb52 100644
--- a/meanas/test/test_fdfd.py
+++ b/meanas/test/test_fdfd.py
@@ -7,6 +7,7 @@ import numpy        # type: ignore
 from .. import fdfd
 from ..fdmath import vec, unvec
 from .utils import assert_close  # , assert_fields_close
+from .conftest import FixtureRequest
 
 
 def test_residual(sim: 'FDResult') -> None:
@@ -53,17 +54,17 @@ def test_poynting_planes(sim: 'FDResult') -> None:
 # Also see conftest.py
 
 @pytest.fixture(params=[1 / 1500])
-def omega(request: pytest.FixtureRequest) -> Iterable[float]:
+def omega(request: FixtureRequest) -> Iterable[float]:
     yield request.param
 
 
 @pytest.fixture(params=[None])
-def pec(request: pytest.FixtureRequest) -> Iterable[Optional[numpy.ndarray]]:
+def pec(request: FixtureRequest) -> Iterable[Optional[numpy.ndarray]]:
     yield request.param
 
 
 @pytest.fixture(params=[None])
-def pmc(request: pytest.FixtureRequest) -> Iterable[Optional[numpy.ndarray]]:
+def pmc(request: FixtureRequest) -> Iterable[Optional[numpy.ndarray]]:
     yield request.param
 
 
@@ -74,7 +75,7 @@ def pmc(request: pytest.FixtureRequest) -> Iterable[Optional[numpy.ndarray]]:
 
 
 @pytest.fixture(params=['diag'])        # 'center'
-def j_distribution(request: pytest.FixtureRequest,
+def j_distribution(request: FixtureRequest,
                    shape: Tuple[int, ...],
                    j_mag: float,
                    ) -> Iterable[numpy.ndarray]:
@@ -103,7 +104,7 @@ class FDResult:
 
 
 @pytest.fixture()
-def sim(request: pytest.FixtureRequest,
+def sim(request: FixtureRequest,
         shape: Tuple[int, ...],
         epsilon: numpy.ndarray,
         dxes: List[List[numpy.ndarray]],
diff --git a/meanas/test/test_fdfd_pml.py b/meanas/test/test_fdfd_pml.py
index ac57750..cf9c05a 100644
--- a/meanas/test/test_fdfd_pml.py
+++ b/meanas/test/test_fdfd_pml.py
@@ -7,6 +7,7 @@ from .. import fdfd
 from ..fdmath import vec, unvec, dx_lists_mut
 #from .utils import assert_close, assert_fields_close
 from .test_fdfd import FDResult
+from .conftest import FixtureRequest
 
 
 def test_pml(sim: FDResult, src_polarity: int) -> None:
@@ -42,34 +43,34 @@ def test_pml(sim: FDResult, src_polarity: int) -> None:
 # Also see conftest.py
 
 @pytest.fixture(params=[1 / 1500])
-def omega(request: pytest.FixtureRequest) -> Iterable[float]:
+def omega(request: FixtureRequest) -> Iterable[float]:
     yield request.param
 
 
 @pytest.fixture(params=[None])
-def pec(request: pytest.FixtureRequest) -> Iterable[Optional[numpy.ndarray]]:
+def pec(request: FixtureRequest) -> Iterable[Optional[numpy.ndarray]]:
     yield request.param
 
 
 @pytest.fixture(params=[None])
-def pmc(request: pytest.FixtureRequest) -> Iterable[Optional[numpy.ndarray]]:
+def pmc(request: FixtureRequest) -> Iterable[Optional[numpy.ndarray]]:
     yield request.param
 
 
 @pytest.fixture(params=[(30, 1, 1),
                         (1, 30, 1),
                         (1, 1, 30)])
-def shape(request: pytest.FixtureRequest) -> Iterable[Tuple[int, ...]]:
+def shape(request: FixtureRequest) -> Iterable[Tuple[int, ...]]:
     yield (3, *request.param)
 
 
 @pytest.fixture(params=[+1, -1])
-def src_polarity(request: pytest.FixtureRequest) -> Iterable[int]:
+def src_polarity(request: FixtureRequest) -> Iterable[int]:
     yield request.param
 
 
 @pytest.fixture()
-def j_distribution(request: pytest.FixtureRequest,
+def j_distribution(request: FixtureRequest,
                    shape: Tuple[int, ...],
                    epsilon: numpy.ndarray,
                    dxes: dx_lists_mut,
@@ -107,7 +108,7 @@ def j_distribution(request: pytest.FixtureRequest,
 
 
 @pytest.fixture()
-def epsilon(request: pytest.FixtureRequest,
+def epsilon(request: FixtureRequest,
             shape: Tuple[int, ...],
             epsilon_bg: float,
             epsilon_fg: float,
@@ -117,7 +118,7 @@ def epsilon(request: pytest.FixtureRequest,
 
 
 @pytest.fixture(params=['uniform'])
-def dxes(request: pytest.FixtureRequest,
+def dxes(request: FixtureRequest,
          shape: Tuple[int, ...],
          dx: float,
          omega: float,
@@ -135,7 +136,7 @@ def dxes(request: pytest.FixtureRequest,
 
 
 @pytest.fixture()
-def sim(request: pytest.FixtureRequest,
+def sim(request: FixtureRequest,
         shape: Tuple[int, ...],
         epsilon: numpy.ndarray,
         dxes: dx_lists_mut,
diff --git a/meanas/test/test_fdtd.py b/meanas/test/test_fdtd.py
index 56fa553..8f5e013 100644
--- a/meanas/test/test_fdtd.py
+++ b/meanas/test/test_fdtd.py
@@ -6,6 +6,7 @@ import numpy        # type: ignore
 
 from .. import fdtd
 from .utils import assert_close, assert_fields_close, PRNG
+from .conftest import FixtureRequest
 
 
 def test_initial_fields(sim: 'TDResult') -> None:
@@ -140,7 +141,7 @@ def test_poynting_planes(sim: 'TDResult') -> None:
 
 
 @pytest.fixture(params=[0.3])
-def dt(request: pytest.FixtureRequest) -> Iterable[float]:
+def dt(request: FixtureRequest) -> Iterable[float]:
     yield request.param
 
 
@@ -158,12 +159,12 @@ class TDResult:
 
 
 @pytest.fixture(params=[(0, 4, 8)])  # (0,)
-def j_steps(request: pytest.fixtureRequest) -> Iterable[Tuple[int, ...]]:
+def j_steps(request: FixtureRequest) -> Iterable[Tuple[int, ...]]:
     yield request.param
 
 
 @pytest.fixture(params=['center', 'random'])
-def j_distribution(request: pytest.FixtureRequest,
+def j_distribution(request: FixtureRequest,
                    shape: Tuple[int, ...],
                    j_mag: float,
                    ) -> Iterable[numpy.ndarray]:
@@ -178,7 +179,7 @@ def j_distribution(request: pytest.FixtureRequest,
 
 
 @pytest.fixture()
-def sim(request: pytest.FixtureRequest,
+def sim(request: FixtureRequest,
         shape: Tuple[int, ...],
         epsilon: numpy.ndarray,
         dxes: List[List[numpy.ndarray]],
diff --git a/meanas/test/utils.py b/meanas/test/utils.py
index 7c8c372..f76b910 100644
--- a/meanas/test/utils.py
+++ b/meanas/test/utils.py
@@ -1,8 +1,10 @@
 from typing import Any
 import numpy        # type: ignore
 
+
 PRNG = numpy.random.RandomState(12345)
 
+
 def assert_fields_close(x: numpy.ndarray,
                         y: numpy.ndarray,
                         *args: Any,