Use compile-fail to ensure the correctness of our type structure

This replaces all "this should fail to compile" comments with an actual
test that they fail to compile. I've attempted to specify as much as I
think is relevant about the error messages, without too tightly coupling
to the exact wording that rustc gives when possible.

I might need to be more loose in the future. It's a shame there's no way
to specify a regex here, because most of the time what I care about is
that it includes the name of a trait that isn't implemented, and the
right error code.

Author: sgrif

Cargo.toml

@@ -7,3 +7,6 @@ authors = ["Sean Griffin <sean@thoughtbot.com>"]
 libc = "*"
 pq-sys = "0.1.*"
 byteorder = "0.3.*"
+
+[dev-dependencies]
+compiletest_rs = "*"

src/tests/find.rs

@@ -13,9 +13,6 @@ fn find() {
     assert_eq!(Ok(Some(User::new(1, "Sean"))), connection.find(&users, &1));
     assert_eq!(Ok(Some(User::new(2, "Tess"))), connection.find(&users, &2));
     assert_eq!(Ok(None::<User>), connection.find(&users, &3));
-    // This should fail type checking, and we should add a test to ensure
-    // it continues to fail to compile.
-    // connection.find(&users, &"1").unwrap();
 }
 
 table! {
@@ -37,8 +34,4 @@ fn find_with_non_serial_pk() {
     assert_eq!(Ok(Some("Sean".to_string())), connection.find(&users, &"Sean"));
     assert_eq!(Ok(Some("Tess".to_string())), connection.find(&users, &"Tess".to_string()));
     assert_eq!(Ok(None::<String>), connection.find(&users, &"Wibble"));
-    // This should fail type checking, and we should add a test to ensure
-    // it continues to fail to compile.
-    // connection.find(&users, &1).unwrap();
 }
-

src/tests/select.rs

@@ -44,18 +44,11 @@ fn with_safe_select() {
         .unwrap();
 
     let select_id = users.select(id);
-    // This should fail type checking, and we should add a test to ensure
-    // it continues to fail to compile.
-    // let select_id = users.select(posts::id);
     let select_name = users.select(name);
     let ids: Vec<_> = connection.query_all(&select_id)
         .unwrap().collect();
     let names: Vec<String> = connection.query_all(&select_name)
         .unwrap().collect();
-    // This should fail type checking, and we should add a test to ensure
-    // it continues to fail to compile.
-    // let names: Vec<String> = connection.query_all(&select_id)
-    //     .unwrap().collect();
 
     assert_eq!(vec![1, 2], ids);
     assert_eq!(vec!["Sean".to_string(), "Tess".to_string()], names);
@@ -72,10 +65,6 @@ fn selecting_multiple_columns() {
         .unwrap();
 
     let source = users.select((name, hair_color));
-    // This should fail type checking, and we should add a test to ensure
-    // it continues to fail to compile.
-    // let source = users.select((posts::title, posts::user_id));
-    // let source = users.select((posts::title, name));
     let expected_data = vec![
         ("Jim".to_string(), Some("Black".to_string())),
         ("Bob".to_string(), Some("Brown".to_string())),
@@ -116,9 +105,6 @@ fn with_select_sql() {
 
     let select_count = users::table.select_sql::<types::BigInt>("COUNT(*)");
     let get_count = || connection.query_one::<_, i64>(&select_count).unwrap();
-    // This should fail type checking, and we should add a test to ensure
-    // it continues to fail to compile.
-    // let actual_count = connection.query_one::<_, String>(&select_count).unwrap();
 
     assert_eq!(Some(2), get_count());
 

tests/compile-fail/find_requires_correct_type.rs

@@ -0,0 +1,24 @@
+#[macro_use]
+extern crate yaqb;
+
+use yaqb::*;
+
+table! {
+    int_primary_key {
+        id -> Serial,
+    }
+}
+
+table! {
+    string_primary_key {
+        id -> VarChar,
+    }
+}
+
+fn main() {
+    let connection = Connection::establish("").unwrap();
+    let one = connection.find(&int_primary_key::table, &"1").unwrap();
+    //~^ ERROR the trait `yaqb::types::ToSql<yaqb::types::Serial>` is not implemented
+    let string = connection.find(&string_primary_key::table, &1).unwrap();
+    //~^ ERROR the trait `yaqb::types::ToSql<yaqb::types::VarChar>` is not implemented
+}

tests/compile-fail/select_carries_correct_result_type_info.rs

@@ -0,0 +1,31 @@
+#[macro_use]
+extern crate yaqb;
+
+use yaqb::*;
+
+table! {
+    users {
+        id -> Serial,
+        name -> VarChar,
+    }
+}
+
+fn main() {
+    use self::users::columns::*;
+    use self::users::table as users;
+
+    let connection = Connection::establish("").unwrap();
+    let select_id = users.select(id);
+    let select_name = users.select(name);
+
+    let ids: Vec<i32> = connection.query_all(&select_name).unwrap().collect();
+    //~^ ERROR the trait `yaqb::query_source::Queriable<yaqb::types::VarChar>` is not implemented for the type `i32`
+    //~| ERROR E0277
+    //~| ERROR E0277
+    //~| ERROR E0277
+    let names: Vec<String> = connection.query_all(&select_id).unwrap().collect();
+    //~^ ERROR the trait `yaqb::query_source::Queriable<yaqb::types::Serial>` is not implemented
+    //~| ERROR E0277
+    //~| ERROR E0277
+    //~| ERROR E0277
+}

tests/compile-fail/select_requires_column_from_same_table.rs

@@ -0,0 +1,26 @@
+#[macro_use]
+extern crate yaqb;
+
+use yaqb::*;
+
+table! {
+    users {
+        id -> Serial,
+        name -> VarChar,
+    }
+}
+
+table! {
+    posts {
+        id -> Serial,
+        title -> VarChar,
+    }
+}
+
+fn main() {
+    let connection = Connection::establish("").unwrap();
+    let select_id = users::table.select(posts::id);
+    //~^ ERROR SelectableColumn
+    let select_id = users::table.select(posts::id);
+    //~^ ERROR E0277
+}

tests/compile-fail/select_sql_still_ensures_result_type.rs

@@ -0,0 +1,18 @@
+#[macro_use]
+extern crate yaqb;
+
+use yaqb::*;
+
+table! {
+    users {
+        id -> Serial,
+        name -> VarChar,
+    }
+}
+
+fn main() {
+    let connection = Connection::establish("").unwrap();
+    let select_count = users::table.select_sql::<types::BigInt>("COUNT(*)");
+    let count = connection.query_one::<_, String>(&select_count).unwrap();
+    //~^ ERROR type mismatch
+}

tests/compile-fail/selecting_multiple_columns_requires_all_must_be_from_selectable_table.rs

@@ -0,0 +1,28 @@
+#[macro_use]
+extern crate yaqb;
+
+use yaqb::*;
+
+table! {
+    users {
+        id -> Serial,
+        name -> VarChar,
+    }
+}
+
+table! {
+    posts {
+        id -> Serial,
+        title -> VarChar,
+        user_id -> Integer,
+    }
+}
+
+fn main() {
+    let connection = Connection::establish("").unwrap();
+    let stuff = users::table.select((posts::id, posts::user_id));
+    //~^ ERROR SelectableColumn
+    //~| ERROR E0277
+    let stuff = users::table.select((posts::id, users::name));
+    //~^ ERROR E0277
+}

tests/compile_tests.rs

@@ -0,0 +1,25 @@
+extern crate compiletest_rs as compiletest;
+
+use std::path::PathBuf;
+use std::env::var;
+
+fn run_mode(mode: &'static str) {
+    let mut config = compiletest::default_config();
+
+    let cfg_mode = mode.parse().ok().expect("Invalid mode");
+
+    config.target_rustcflags = Some("-L target/debug/ -L target/debug/deps/".to_owned());
+    if let Ok(name) = var::<&str>("TESTNAME") {
+        let s : String = name.to_owned();
+        config.filter = Some(s)
+    }
+    config.mode = cfg_mode;
+    config.src_base = PathBuf::from(format!("tests/{}", mode));
+
+    compiletest::run_tests(&config);
+}
+
+#[test]
+fn compile_test() {
+    run_mode("compile-fail");
+}