feat: Support adding a single new table factory to SessionStateBuilder (

#12563)

datafusion/core/src/execution/session_state.rs

@@ -1193,6 +1193,18 @@ impl SessionStateBuilder {
         self
     }
 
+    /// Add a [`TableProviderFactory`] to the map of factories
+    pub fn with_table_factory(
+        mut self,
+        key: String,
+        table_factory: Arc<dyn TableProviderFactory>,
+    ) -> Self {
+        let mut table_factories = self.table_factories.unwrap_or_default();
+        table_factories.insert(key, table_factory);
+        self.table_factories = Some(table_factories);
+        self
+    }
+
     /// Set the map of [`TableProviderFactory`]s
     pub fn with_table_factories(
         mut self,
@@ -1929,4 +1941,22 @@ mod tests {
             Optimizer::default().rules.len() + 1
         );
     }
+
+    #[test]
+    fn test_with_table_factories() -> Result<()> {
+        use crate::test_util::TestTableFactory;
+
+        let state = SessionStateBuilder::new().build();
+        let table_factories = state.table_factories();
+        assert!(table_factories.is_empty());
+
+        let table_factory = Arc::new(TestTableFactory {});
+        let state = SessionStateBuilder::new()
+            .with_table_factory("employee".to_string(), table_factory)
+            .build();
+        let table_factories = state.table_factories();
+        assert_eq!(table_factories.len(), 1);
+        assert!(table_factories.contains_key("employee"));
+        Ok(())
+    }
 }