Minor: Clarify documentation on PruningStatistics and make test match (…

…#10004)

datafusion/core/src/physical_optimizer/pruning.rs

@@ -105,19 +105,23 @@ pub trait PruningStatistics {
     fn num_containers(&self) -> usize;
 
     /// Return the number of null values for the named column as an
-    /// `Option<UInt64Array>`.
+    /// [`UInt64Array`]
     ///
     /// See [`Self::min_values`] for when to return `None` and null values.
     ///
     /// Note: the returned array must contain [`Self::num_containers`] rows
+    ///
+    /// [`UInt64Array`]: arrow::array::UInt64Array
     fn null_counts(&self, column: &Column) -> Option<ArrayRef>;
 
     /// Return the number of rows for the named column in each container
-    /// as an `Option<UInt64Array>`.
+    /// as an [`UInt64Array`].
     ///
     /// See [`Self::min_values`] for when to return `None` and null values.
     ///
     /// Note: the returned array must contain [`Self::num_containers`] rows
+    ///
+    /// [`UInt64Array`]: arrow::array::UInt64Array
     fn row_counts(&self, column: &Column) -> Option<ArrayRef>;
 
     /// Returns [`BooleanArray`] where each row represents information known
@@ -1519,6 +1523,7 @@ mod tests {
         array::{BinaryArray, Int32Array, Int64Array, StringArray},
         datatypes::{DataType, TimeUnit},
     };
+    use arrow_array::UInt64Array;
     use datafusion_common::{ScalarValue, ToDFSchema};
     use datafusion_expr::execution_props::ExecutionProps;
     use datafusion_expr::expr::InList;
@@ -1684,10 +1689,10 @@ mod tests {
         /// there are containers
         fn with_null_counts(
             mut self,
-            counts: impl IntoIterator<Item = Option<i64>>,
+            counts: impl IntoIterator<Item = Option<u64>>,
         ) -> Self {
             let null_counts: ArrayRef =
-                Arc::new(counts.into_iter().collect::<Int64Array>());
+                Arc::new(counts.into_iter().collect::<UInt64Array>());
 
             self.assert_invariants();
             self.null_counts = Some(null_counts);
@@ -1698,10 +1703,10 @@ mod tests {
         /// there are containers
         fn with_row_counts(
             mut self,
-            counts: impl IntoIterator<Item = Option<i64>>,
+            counts: impl IntoIterator<Item = Option<u64>>,
         ) -> Self {
             let row_counts: ArrayRef =
-                Arc::new(counts.into_iter().collect::<Int64Array>());
+                Arc::new(counts.into_iter().collect::<UInt64Array>());
 
             self.assert_invariants();
             self.row_counts = Some(row_counts);
@@ -1753,13 +1758,13 @@ mod tests {
             self
         }
 
-        /// Add null counts for the specified columm.
+        /// Add null counts for the specified column.
         /// There must be the same number of null counts as
         /// there are containers
         fn with_null_counts(
             mut self,
             name: impl Into<String>,
-            counts: impl IntoIterator<Item = Option<i64>>,
+            counts: impl IntoIterator<Item = Option<u64>>,
         ) -> Self {
             let col = Column::from_name(name.into());
 
@@ -1775,13 +1780,13 @@ mod tests {
             self
         }
 
-        /// Add row counts for the specified columm.
+        /// Add row counts for the specified column.
         /// There must be the same number of row counts as
         /// there are containers
         fn with_row_counts(
             mut self,
             name: impl Into<String>,
-            counts: impl IntoIterator<Item = Option<i64>>,
+            counts: impl IntoIterator<Item = Option<u64>>,
         ) -> Self {
             let col = Column::from_name(name.into());
 
@@ -1797,7 +1802,7 @@ mod tests {
             self
         }
 
-        /// Add contained information for the specified columm.
+        /// Add contained information for the specified column.
         fn with_contained(
             mut self,
             name: impl Into<String>,