docs: license and module docstrings

datafusion/sqllogictest/src/engines/datafusion_engine/mod.rs

@@ -1,3 +1,22 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+/// DataFusion engine implementation for sqllogictest.
+
 mod error;
 mod normalize;
 mod runner;

datafusion/sqllogictest/src/engines/mod.rs

@@ -13,6 +13,10 @@
 // "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 // KIND, either express or implied.  See the License for the
 // specific language governing permissions and limitations
+// under the License.
+
+/// Implementation of sqllogictest for datafusion. Optionally uses postgres for
+/// comparison, if the `postgres` feature is enabled.
 
 mod conversion;
 mod datafusion_engine;

datafusion/sqllogictest/src/engines/postgres_engine/mod.rs

@@ -15,6 +15,8 @@
 // specific language governing permissions and limitations
 // under the License.
 
+/// Postgres engine implementation for sqllogictest.
+
 use std::path::{Path, PathBuf};
 use std::str::FromStr;