Implement ResponseWriterStub for testing

minisql/src/interpreter2.rs

@@ -174,6 +174,7 @@ mod tests {
     use super::*;
     use crate::operation::Operation;
     use crate::schema::Column;
+    use crate::response_writer::ResponseWriterStub;
     use crate::type_system::{DbType, IndexableValue, Value};
     use std::collections::HashSet;
 
@@ -202,8 +203,12 @@ mod tests {
         let users_schema = users_schema();
         let users = users_schema.table_name().clone();
 
+        let db_path = Path::new("db-test-0");
+
+        let mut response_writer = ResponseWriterStub::new();
+
         // state
-        //     .interpret(Operation::CreateTable(users_schema))
+        //     .interpret(db_path, &mut response_writer, Operation::CreateTable(users_schema)).await
         //     .unwrap();
 
         // assert!(state.tables.len() == 1);

minisql/src/response_writer.rs

@@ -34,3 +34,53 @@ pub trait ResponseWriter {
     async fn write_table_row(&mut self, row: &RestrictedRow) -> anyhow::Result<()>;
     async fn write_command_complete(&mut self, status: CompleteStatus) -> anyhow::Result<()>;
 }
+
+// ===Stub implementation for testing===
+//
+pub struct ResponseWriterStub {}
+
+impl ResponseWriterStub {
+    pub fn new() -> Self {
+        ResponseWriterStub {}
+    }
+}
+
+#[async_trait]
+impl ResponseWriter for ResponseWriterStub
+{
+    async fn write_table_header(
+        &mut self,
+        table_schema: &TableSchema,
+        columns: &ColumnSelection,
+    ) -> anyhow::Result<()> {
+        let column_names = table_schema.get_columns();
+        for &column in columns {
+            let column_name = column_names[column];
+            print!("{}, ", column_name)
+        }
+        println!();
+
+        Ok(())
+    }
+
+    async fn write_table_row(&mut self, row: &RestrictedRow) -> anyhow::Result<()> {
+        for (_, value) in row.iter() {
+            print!("{:?}", value)
+        }
+        println!();
+
+        Ok(())
+    }
+
+    async fn write_command_complete(&mut self, status: CompleteStatus) -> anyhow::Result<()> {
+        use CompleteStatus::*;
+        match status {
+            Insert { oid, rows } => println!("oid = {}, rows = {}", oid, rows),
+            Delete(count) => println!("Deleted {}", count),
+            Select(count) => println!("Selected {}", count),
+            CreateTable => println!("Table created"),
+            CreateIndex => println!("Index created"),
+        }
+        Ok(())
+    }
+}