fix: non-visual QA greyscale TDE-832 (#593)

* fix: non-visual qa handle greyscale TDE-832

* fix: revert variable name and fix typo

* fix: formatting

* fix: remove print statement

scripts/files/file_tiff.py

@@ -199,8 +199,8 @@ def is_error_type(self, error_type: FileTiffErrorType) -> bool:
         return False
 
     def check_no_data(self, gdalinfo: GdalInfo) -> None:
-        """Add a Non Visual QA error if there is no "noDataValue" or the "noDataValue" is not equal to 255
-        or -9999 for DEM in the "bands".
+        """Add a Non Visual QA error if there is no "noDataValue" and no alpha band for non-DEMs,
+        or the "noDataValue" is not equal to 255, or -9999 for DEM in the "bands".
 
         Args:
             gdalinfo: `gdalinfo` output
@@ -240,7 +240,7 @@ def is_no_data(self, gdalinfo: GdalInfo) -> bool:
         return False
 
     def check_band_count(self, gdalinfo: GdalInfo) -> None:
-        """Add a Non Visual QA error if there is not exactly 3 or 4 bands found.
+        """Add a Non Visual QA error if there is not exactly 3 or 4 bands found, or 1 band if DEM.
 
         Args:
             gdalinfo: `gdalinfo` output
@@ -272,22 +272,23 @@ def check_srs(self, gdalsrsinfo_tif: bytes) -> None:
             self.add_error(error_type=FileTiffErrorType.SRS, error_message="srs not defined")
 
     def check_color_interpretation(self, gdalinfo: GdalInfo) -> None:
-        """Add a Non Visual QA error if the colors don't match RGB.
+        """Add a Non Visual QA error if the colors don't match RGB or greyscale.
 
         Args:
             gdalinfo: `gdalinfo` output
         """
         bands = gdalinfo["bands"]
         missing_bands = []
         band_colour_ints = {1: "Red", 2: "Green", 3: "Blue"}
+        band_greyscale_ints = {1: "Gray", 2: "Gray", 3: "Gray"}
         optional_colour_ints = {4: "Alpha"}
         if self._tiff_type == "DEM":
             band_colour_ints = {1: "Gray"}
         n = 1
         for band in bands:
             colour_int = band["colorInterpretation"]
             if n in band_colour_ints:
-                if colour_int != band_colour_ints[n]:
+                if colour_int not in (band_colour_ints[n], band_greyscale_ints[n]):
                     missing_bands.append(f"band {n} {colour_int}")
             elif n in optional_colour_ints:
                 if colour_int != optional_colour_ints[n]:

scripts/files/tests/file_tiff_test.py

@@ -111,9 +111,9 @@ def test_check_band_count_invalid_3_DEM() -> None:
     assert file_tiff.get_errors()
 
 
-def test_check_color_interpretation_valid() -> None:
+def test_check_color_interpretation_valid_rgb() -> None:
     """
-    tests check_color_interpretation with the correct color interpretation
+    tests check_color_interpretation with the correct RGB color interpretation
     """
     gdalinfo = fake_gdal_info()
     add_band(gdalinfo, color_interpretation="Red")
@@ -126,6 +126,21 @@ def test_check_color_interpretation_valid() -> None:
     assert not file_tiff.get_errors()
 
 
+def test_check_color_interpretation_valid_greyscale() -> None:
+    """
+    tests check_color_interpretation with the correct greyscale color interpretation
+    """
+    gdalinfo = fake_gdal_info()
+    add_band(gdalinfo, color_interpretation="Gray")
+    add_band(gdalinfo, color_interpretation="Gray")
+    add_band(gdalinfo, color_interpretation="Gray")
+
+    file_tiff = FileTiff(["test"])
+    file_tiff.check_color_interpretation(gdalinfo)
+
+    assert not file_tiff.get_errors()
+
+
 def test_check_color_interpretation_invalid() -> None:
     """
     tests check_color_interpretation with the incorrect color interpretation