fix: be specific about nodata being None (#363)

* fix: be specific about nodata being None

* fix: format

* fix: update comment and correctly format if statement

scripts/files/file_tiff.py

@@ -99,9 +99,10 @@ def check_no_data(self, gdalinfo: GdalInfo) -> None:
                 )
 
     def is_no_data(self, gdalinfo: GdalInfo) -> bool:
-        """return True if bands have a "noDataValue" and it is set to 255."""
+        """return True if bands have a "noDataValue" set."""
         bands = gdalinfo["bands"]
-        if "noDataValue" in bands[0] and bands[0]["noDataValue"]:
+        # 0 in noDataValue can return false unless specific here about None
+        if "noDataValue" in bands[0] and bands[0]["noDataValue"] is not None:
             return True
         return False
 

scripts/files/tests/file_tiff_test.py

@@ -155,9 +155,9 @@ def test_check_no_data_no_value() -> None:
     assert file_tiff.get_errors()
 
 
-def test_is_no_data_true() -> None:
+def test_is_no_data_true_255() -> None:
     """
-    tests is_no_data when the input layer that has no_data value assigned
+    tests is_no_data when the input layer that has 255 no_data value assigned
     """
     gdalinfo = fake_gdal_info()
     add_band(gdalinfo, no_data_value=255)
@@ -166,6 +166,17 @@ def test_is_no_data_true() -> None:
     assert file_tiff.is_no_data(gdalinfo)
 
 
+def test_is_no_data_true_0() -> None:
+    """
+    tests is_no_data when the input layer that has 0 no_data value assigned
+    """
+    gdalinfo = fake_gdal_info()
+    add_band(gdalinfo, no_data_value=0)
+
+    file_tiff = FileTiff("test")
+    assert file_tiff.is_no_data(gdalinfo)
+
+
 def test_is_no_data_false() -> None:
     """
     tests is_no_data when the input layer that does not have no_data value assigned