Fix: if "db" mode and hz is 0 return 0 not inf

itu_r_468_weighting/filter.py

@@ -42,10 +42,8 @@ def r468(frequency_hz: Union[int, float], khz_option: str, returns: str) -> floa
         If parameter `khz_option` is not equal to `1khz` or `2khz`.
     """
 
-    if frequency_hz > 0:
+    if frequency_hz >= 0:
         pass
-    elif frequency_hz == 0:
-        return inf
     else:
         raise ValueError
 
@@ -70,9 +68,9 @@ def r468(frequency_hz: Union[int, float], khz_option: str, returns: str) -> floa
 
     if returns == "db":
         if khz_option == "1khz":
-            return DB_GAIN_1KHZ + 20 * log10(r_itu)
+            return 0.0 if r_itu == 0.0 else DB_GAIN_1KHZ + 20.0 * log10(r_itu)
         elif khz_option == "2khz":
-            return DB_GAIN_2KHZ + 20 * log10(r_itu)
+            return 0.0 if r_itu == 0.0 else DB_GAIN_2KHZ + 20.0 * log10(r_itu)
         else:
             raise ValueError
     elif returns == "factor":

setup.py

@@ -9,7 +9,7 @@
 
 setup(
     name="itu-r-468-weighting",
-    version="2.0.2",
+    version="2.0.3",
     description="A zero dependency Python ITU-R 468 noise weighting filter (1 kHz and 2 kHz)",
     long_description=long_description,
     long_description_content_type="text/markdown",

tests/test_weighting_filter_r468.py

@@ -44,8 +44,8 @@ def test_value_lt_0_that_must_raise_value_error(hz, khz_option, returns):
         (0, "2khz", "factor"),
     ],
 )
-def test_value_of_0_that_must_return_inf(hz, khz_option, returns):
-    assert r468(hz, khz_option, returns) == inf
+def test_hz_value_of_0_must_return_0(hz, khz_option, returns):
+    assert r468(hz, khz_option, returns) == 0.0
 
 
 @pytest.mark.parametrize(