Raise ProviderTileNotFoundError instead of returning (#2101)

* Raise provider error

Fix typo that returned ProviderTileNotFoundError instead of raising it

* Fix tests

Author: webb-ben

pygeoapi/provider/mvt_postgresql.py

@@ -151,7 +151,7 @@ def get_tiles(self, layer='default', tileset=None,
         ]
         if not self.is_in_limits(tileset_schema, z, x, y):
             LOGGER.warning(f'Tile {z}/{x}/{y} not found')
-            return ProviderTileNotFoundError
+            raise ProviderTileNotFoundError
 
         storage_srid = get_crs_from_uri(self.storage_crs).to_string()
         out_srid = get_crs_from_uri(tileset_schema.crs).to_string()

tests/provider/test_postgresql_mvt_provider.py

@@ -271,11 +271,11 @@ def test_get_tiles_WebMercatorQuad(config):
 
     # Tile does not exist in matrixset
     z, x, y = 1, 1000000, 1000000
-    result = p.get_tiles(
-        tileset=tileset,
-        z=z, x=x, y=y
-    )
-    assert result == ProviderTileNotFoundError
+    with pytest.raises(ProviderTileNotFoundError):
+        p.get_tiles(
+            tileset=tileset,
+            z=z, x=x, y=y
+        )
 
 
 def test_get_tiles_WorldCRS84Quad(config):
@@ -311,8 +311,8 @@ def test_get_tiles_WorldCRS84Quad(config):
 
     # Tile does not exist in matrixset
     z, x, y = 1, 1000000, 1000000
-    result = p.get_tiles(
-        tileset=tileset,
-        z=z, x=x, y=y
-    )
-    assert result == ProviderTileNotFoundError
+    with pytest.raises(ProviderTileNotFoundError):
+        p.get_tiles(
+            tileset=tileset,
+            z=z, x=x, y=y
+        )