Pick up clippy.toml in ui-cargo tests.

Author: daxpedda

tests/compile-test.rs

@@ -214,6 +214,7 @@ fn run_ui_cargo(config: &mut compiletest::Config) {
                         Some("main.rs") => {},
                         _ => continue,
                     }
+                    set_var("CLIPPY_CONF_DIR", case.path());
                     let paths = compiletest::common::TestPaths {
                         file: file_path,
                         base: config.src_base.clone(),
@@ -241,9 +242,11 @@ fn run_ui_cargo(config: &mut compiletest::Config) {
     let tests = compiletest::make_tests(&config);
 
     let current_dir = env::current_dir().unwrap();
+    let conf_dir = var("CLIPPY_CONF_DIR").unwrap_or_default();
     let filter = env::var("TESTNAME").ok();
     let res = run_tests(&config, &filter, tests);
     env::set_current_dir(current_dir).unwrap();
+    set_var("CLIPPY_CONF_DIR", conf_dir);
 
     match res {
         Ok(true) => {},