Testing: Add no cover to numba and fft functions

Author: CSSFrancis

diffsims/pattern/detector_functions.py

@@ -322,7 +322,7 @@ def _subpixel_gaussian(
     shape: Tuple[int, int],
     sigma: float,
     clip_threshold: float = 1,
-) -> np.ndarray:
+) -> np.ndarray:  # pragma: no cover
     out = np.zeros(shape)
 
     # Pre-calculate the constants

diffsims/utils/fourier_transform.py

@@ -216,15 +216,15 @@ def plan_ifft(
         )
         return plan, plan.input_array
 
-except ImportError:
+except ImportError:  # pragma: no cover
     # Only scipy has a next_fast_len, usually numpy is a little faster
     # (note they are not identical)
     from scipy.fftpack import fftn, ifftn, ifftshift, fftshift, next_fast_len
     from numpy.fft import fftn, ifftn, ifftshift, fftshift
 
     _fftn, _ifftn = fftn, ifftn
 
-    def plan_fft(A, n=None, axis=None, norm=None, **_):
+    def plan_fft(A, n=None, axis=None, norm=None, **_):  # pragma: no cover
         """
         Plans an fft for repeated use. Parameters are the same as for `pyfftw`'s `fftn`
         which are, where possible, the same as the `numpy` equivalents.