Added a tables listing.

src/lib.rs

@@ -1,6 +1,8 @@
-use async_graphql::{EmptySubscription, Object, Result, Schema};
+use async_graphql::{Context, EmptySubscription, Object, Result, Schema};
+use async_std::sync::RwLock;
 use serde_json;
 
+#[derive(Clone)]
 struct Table {
     name: String,
 }
@@ -25,14 +27,25 @@ impl Query {
     async fn pointless(&self) -> String {
         "this is pointless.".to_string()
     }
+
+    async fn tables(&self, ctx: &Context<'_>) -> Vec<Table> {
+        ctx.data::<RwLock<Vec<Table>>>()
+            .unwrap()
+            .read()
+            .await
+            .to_vec()
+    }
 }
 
 struct Mutation;
 
 #[Object]
 impl Mutation {
-    async fn create_table(&self, name: String) -> Result<Option<Table>> {
-        Ok(Some(Table::new(name).await))
+    async fn create_table(&self, ctx: &Context<'_>, name: String) -> Result<Option<Table>> {
+        let mut tables = ctx.data::<RwLock<Vec<Table>>>().unwrap().write().await;
+        let output = Table::new(name).await;
+        tables.push(output.clone());
+        Ok(Some(output))
     }
 }
 
@@ -43,8 +56,11 @@ pub struct Database {
 
 impl Database {
     pub fn new() -> Self {
+        let tables: Vec<Table> = Vec::new();
         Self {
-            schema: Schema::new(Query, Mutation, EmptySubscription),
+            schema: Schema::build(Query, Mutation, EmptySubscription)
+                .data(RwLock::new(tables))
+                .finish(),
         }
     }
 
@@ -70,6 +86,24 @@ mod queries {
             expected
         )
     }
+
+    #[async_std::test]
+    async fn list_tables() {
+        let db = Database::new();
+        db.execute(r#"mutation {createTable(name: "fred"){name}}"#)
+            .await;
+        db.execute(r#"mutation {createTable(name: "barney"){name}}"#)
+            .await;
+        let output = db.execute(r#"{tables{name}}"#).await;
+        let expected = r#"{"data":{"tables":[{"name":"fred"},{"name":"barney"}]}}"#;
+        assert!(
+            output == expected,
+            "\n\n{}\nGot:  {}\nWant: {}\n\n",
+            &db.schema.sdl(),
+            output,
+            expected
+        );
+    }
 }
 
 #[cfg(test)]