enh: use custom error BadFFTFilterError for interfere base input

qpretrieve/interfere/__init__.py

@@ -1,3 +1,4 @@
 # flake8: noqa: F401
+from .base import BadFFTFilterError
 from .if_oah import OffAxisHologram
 from .if_qlsi import QLSInterferogram

qpretrieve/interfere/base.py

@@ -7,6 +7,10 @@
 from ..data_input import check_data_input_format, revert_to_data_input_format
 
 
+class BadFFTFilterError(ValueError):
+    pass
+
+
 class BaseInterferogram(ABC):
     default_pipeline_kws = {
         "filter_name": "disk",
@@ -57,18 +61,18 @@ def __init__(self, data, fft_interface: str | FFTFilter = "auto",
 
         """
         if fft_interface is None:
-            raise ValueError(
+            raise BadFFTFilterError(
                 "`fft_interface` is set to None. If you want qpretrieve to "
                 "find the best FFT interface, set it to 'auto'. "
-                "If you trying to use `FFTFilterPyFFTW`, "
+                "If you are trying to use `FFTFilterPyFFTW`, "
                 "you must first install the pyfftw package.")
         if fft_interface == 'auto':
             self.ff_iface = get_best_interface()
         else:
             if fft_interface in get_available_interfaces():
                 self.ff_iface = fft_interface
             else:
-                raise ValueError(
+                raise BadFFTFilterError(
                     f"User-chosen FFT Interface '{fft_interface}' is not "
                     f"available. The available interfaces are: "
                     f"{get_available_interfaces()}.\n"

tests/test_fourier_base.py

@@ -121,10 +121,16 @@ def test_scale_to_filter_oah():
 
 
 def test_bad_fft_interface_input():
+    """Fails because inputting PyFFTW without installing defaults to None"""
     data = np.load(data_path / "hologram_cell.npz")
     image = data["data"]
 
-    with pytest.raises(ValueError):
+    with pytest.raises(
+            interfere.BadFFTFilterError,
+            match="`fft_interface` is set to None. If you want qpretrieve to "
+                  "find the best FFT interface, set it to 'auto'. "
+                  "If you are trying to use `FFTFilterPyFFTW`, "
+                  "you must first install the pyfftw package."):
         interfere.OffAxisHologram(image, fft_interface=None)
 
 

tests/test_interfere_base.py

@@ -33,11 +33,14 @@ def test_interfere_base_choose_interface():
 
 def test_interfere_base_bad_interface():
     edata = np.load(data_path / "hologram_cell.npz")
+    bad_name = "MyReallyCoolFFTInterface"
 
-    with pytest.raises(ValueError):
+    with pytest.raises(
+            qpretrieve.interfere.BadFFTFilterError,
+            match=f"User-chosen FFT Interface '{bad_name}' is not available."):
         _ = qpretrieve.OffAxisHologram(
             data=edata["data"],
-            fft_interface="MyReallyCoolFFTInterface")
+            fft_interface=bad_name)
 
 
 def test_interfere_base_orig_data_fmt():