Split RLS into bin/lib and move some tests to Cargo integration test format

.gitignore

@@ -2,4 +2,3 @@
 .idea
 
 target
-test_data/Cargo.lock

Cargo.toml

@@ -10,6 +10,14 @@ categories = ["development-tools"]
 
 build = "build.rs"
 
+[lib]
+name = "rls"
+doctest = false
+
+[[bin]]
+name = "rls"
+test = false
+
 [dependencies]
 cargo = { git = "https://github.com/rust-lang/cargo", rev = "2a9f16da7ffc4877aacf7547bac705f0d82de2d6" }
 cargo_metadata = "0.6"

build.rs

@@ -8,6 +8,9 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+use std::path::Path;
+use std::env;
+
 fn main() {
     println!("cargo:rerun-if-changed=build.rs");
     println!("cargo:rerun-if-env-changed=CFG_RELEASE_CHANNEL");
@@ -20,4 +23,8 @@ fn main() {
         "cargo:rustc-env=COMMIT_DATE={}",
         rustc_tools_util::get_commit_date().unwrap_or_default()
     );
+    println!(
+        "cargo:rustc-env=FIXTURES_DIR={}",
+        Path::new(&env::var("CARGO_MANIFEST_DIR").unwrap()).join("tests/fixtures").display()
+    );
 }

src/actions/diagnostics.rs

@@ -344,15 +344,18 @@ impl IsWithin for Range {
 
 /// Tests for formatted messages from the compilers json output
 /// run cargo with `--message-format=json` to generate the json for new tests and add .json
-/// message files to '$(crate::test::FIXTURES_DIR)/compiler_message/'
+/// message files to '$FIXTURES_DIR/compiler_message/'
 #[cfg(test)]
 mod diagnostic_message_test {
     use super::*;
     use languageserver_types::Position;
-    pub(super) use crate::test::FIXTURES_DIR;
+
+    pub(super) fn fixtures_dir() -> &'static Path {
+        Path::new(env!("FIXTURES_DIR"))
+    }
 
     pub(super) fn read_fixture(path: impl AsRef<Path>) -> String {
-        std::fs::read_to_string(FIXTURES_DIR.join(path.as_ref())).unwrap()
+        std::fs::read_to_string(fixtures_dir().join(path.as_ref())).unwrap()
     }
 
     pub(super) fn parse_compiler_message(