feat(rust/sedona-testing): Add test helpers for loading raster test data

rust/sedona-testing/src/data.rs

@@ -125,6 +125,33 @@ pub fn sedona_testing_dir() -> Result<String> {
     )
 }
 
+/// Get the path to a raster test file from the sedona-testing data directory.
+///
+/// # Arguments
+/// * `name` - The name of the raster file (e.g., "test1.tiff", "test4.tiff")
+///
+/// # Returns
+/// The full path to the raster test file if it exists.
+///
+/// # Example
+/// ```ignore
+/// let path = test_raster("test4.tiff")?;
+/// ```
+pub fn test_raster(name: &str) -> Result<String> {
+    let base = sedona_testing_dir()?;
+    let path = format!("{}/data/raster/{}", base, name);
+    if fs::exists(&path)? {
+        Ok(path)
+    } else {
+        sedona_internal_err!(
+            "sedona-testing raster file '{}' not found at '{}', \
+             run submodules/download-assets.py or check the file name",
+            name,
+            path
+        )
+    }
+}
+
 #[cfg(test)]
 mod test {
     use super::*;
@@ -172,4 +199,18 @@ mod test {
         env::remove_var("SEDONA_TESTING_DIR");
         assert!(maybe_dir.is_ok());
     }
+
+    #[test]
+    fn test_raster_resolves() {
+        // Test that test_raster can find existing raster files
+        let path = test_raster("test4.tiff");
+        assert!(path.is_ok(), "Failed to find test4.tiff: {:?}", path.err());
+        let path_str = path.unwrap();
+        assert!(path_str.ends_with("test4.tiff"));
+        assert!(fs::exists(&path_str).unwrap());
+
+        // Test that non-existent files return an error
+        let err = test_raster("nonexistent.tiff");
+        assert!(err.is_err());
+    }
 }

rust/sedona-testing/src/rasters.rs

@@ -184,6 +184,43 @@ pub fn build_noninvertible_raster() -> StructArray {
     builder.finish().expect("finish")
 }
 
+/// Builds a single-band raster from raw bytes for tests.
+pub fn raster_from_single_band(
+    width: usize,
+    height: usize,
+    data_type: BandDataType,
+    band_bytes: &[u8],
+    crs: Option<&str>,
+) -> StructArray {
+    let mut builder = RasterBuilder::new(1);
+    let metadata = RasterMetadata {
+        width: width as u64,
+        height: height as u64,
+        upperleft_x: 0.0,
+        upperleft_y: 0.0,
+        scale_x: 1.0,
+        scale_y: -1.0,
+        skew_x: 0.0,
+        skew_y: 0.0,
+    };
+
+    builder.start_raster(&metadata, crs).expect("start raster");
+    builder
+        .start_band(BandMetadata {
+            datatype: data_type,
+            nodata_value: None,
+            storage_type: StorageType::InDb,
+            outdb_url: None,
+            outdb_band_id: None,
+        })
+        .expect("start band");
+    builder.band_data_writer().append_value(band_bytes);
+    builder.finish_band().expect("finish band");
+    builder.finish_raster().expect("finish raster");
+
+    builder.finish().expect("finish")
+}
+
 /// Determine if this tile contains a corner of the overall grid and return its position
 /// Returns Some(position) if this tile contains a corner, None otherwise
 fn get_corner_position(