Update hello-world exercise to work as a query

exercises/practice/hello-world/.meta/example.sql

@@ -1,4 +1 @@
-INSERT INTO
-  hello_world (greeting)
-VALUES
-  ('Hello, World!');
+SELECT "Hello, World!";

exercises/practice/hello-world/create_fixture.sql

@@ -1,3 +0,0 @@
-DROP TABLE IF EXISTS hello_world;
-
-CREATE TABLE hello_world (greeting TEXT);

exercises/practice/hello-world/hello-world.sql

@@ -1,4 +1 @@
-INSERT INTO
-  hello_world (greeting)
-VALUES
-  ('Goodbye, Mars!');
+SELECT "Goodbye, Mars!";

exercises/practice/hello-world/hello-world_test.sql

@@ -10,6 +10,15 @@ VALUES
     'Hello, World!'
   );
 
+.mode csv
+.output user_output.csv
+.read hello-world.sql
+.output
+
+DROP TABLE IF EXISTS hello_world;
+CREATE TABLE hello_world (greeting TEXT);
+.import user_output.csv hello_world
+
 -- Comparison of user input and the tests updates the status for each test:
 UPDATE tests
 SET

exercises/practice/hello-world/test_setup.sql

@@ -1,7 +1,7 @@
 -- Create database:
 .read ./create_fixture.sql
 -- Read user student solution and save any output as markdown in user_output.md:
-.mode markdown
+.mode list
 .output user_output.md
 .read ./hello-world.sql
 .output