Improve compiletest codegen test dependency resolution.

In this commit, Rocket's codegen tests now search for the correct
library to depend on, independent of compiletest. This solution should
be robust against platform differences.

codegen/tests/compile-fail.rs

@@ -1,6 +0,0 @@
-mod compiletest;
-
-#[test]
-fn compilefail() {
-    compiletest::run(compiletest::Mode::CompileFail);
-}

codegen/tests/compiletest.rs

@@ -1,27 +1,93 @@
-extern crate compiletest_rs;
+extern crate compiletest_rs as compiletest;
 
-use std::path::PathBuf;
+use std::io;
+use std::path::{Path, PathBuf};
 
-pub use self::compiletest_rs::common::Mode;
-pub use self::compiletest_rs::{Config, run_tests};
-
-pub fn run(mode: Mode) {
-    let mut config = Config::default();
-    config.mode = mode;
-    config.src_base = PathBuf::from(format!("tests/{}", mode));
-
-    #[cfg(debug_assertions)]
-    let flags = [
-        "-L crate=../target/debug/",
-        "-L dependency=../target/debug/deps/",
-    ].join(" ");
-
-    #[cfg(not(debug_assertions))]
-    let flags = [
-        "-L crate=../target/release/",
-        "-L dependency=../target/release/deps/",
-    ].join(" ");
-
-    config.target_rustcflags = Some(flags);
-    run_tests(&config);
+#[derive(Copy, Clone)]
+enum Kind {
+    Dynamic, Static
+}
+
+impl Kind {
+    fn extension(self) -> &'static str {
+        match self {
+            #[cfg(windows)] Kind::Dynamic => ".dll",
+            #[cfg(all(unix, target_os = "macos"))] Kind::Dynamic => ".dylib",
+            #[cfg(all(unix, not(target_os = "macos")))] Kind::Dynamic => ".so",
+            Kind::Static => ".rlib"
+        }
+    }
+
+    fn prefix(self) -> &'static str {
+        #[cfg(windows)] { "" }
+        #[cfg(not(windows))] { "lib" }
+    }
+}
+
+fn target_path() -> PathBuf {
+    #[cfg(debug_assertions)] const ENVIRONMENT: &str = "debug";
+    #[cfg(not(debug_assertions))] const ENVIRONMENT: &str = "release";
+
+    Path::new(env!("CARGO_MANIFEST_DIR"))
+        .parent().unwrap()
+        .join("target")
+        .join(ENVIRONMENT)
+}
+
+fn link_flag(flag: &str, lib: &str, rel_path: &[&str]) -> String {
+    let mut path = target_path();
+    for component in rel_path {
+        path = path.join(component);
+    }
+
+    format!("{} {}={}", flag, lib, path.display())
+}
+
+fn extern_dep(name: &str, kind: Kind) -> io::Result<String> {
+    let deps_root = target_path().join("deps");
+    let dep_name = format!("{}{}", kind.prefix(), name);
+
+    let mut dep_path: Option<PathBuf> = None;
+    for entry in deps_root.read_dir().expect("read_dir call failed") {
+        let entry = entry?;
+        let filename = entry.file_name();
+        let filename = filename.to_string_lossy();
+        let lib_name = filename.split('.').next().unwrap().split('-').next().unwrap();
+
+        if lib_name == dep_name && filename.ends_with(kind.extension()) {
+            if let Some(ref mut existing) = dep_path {
+                if entry.metadata()?.created()? > existing.metadata()?.created()? {
+                    *existing = entry.path().into();
+                }
+            } else {
+                dep_path = Some(entry.path().into());
+            }
+        }
+    }
+
+    let dep = dep_path.ok_or_else(|| io::Error::from(io::ErrorKind::NotFound))?;
+    let filename = dep.file_name().ok_or_else(|| io::Error::from(io::ErrorKind::InvalidData))?;
+    Ok(link_flag("--extern", name, &["deps", &filename.to_string_lossy()]))
+}
+
+fn run_mode(mode: &'static str) {
+    let mut config = compiletest::Config::default();
+    config.mode = mode.parse().expect("Invalid mode");
+    config.src_base = format!("tests/{}", mode).into();
+    config.clean_rmeta();
+
+    config.target_rustcflags = Some([
+                                    link_flag("-L", "crate", &[]),
+                                    link_flag("-L", "dependency", &["deps"]),
+                                    extern_dep("rocket_codegen", Kind::Dynamic).expect("find codegen dep"),
+                                    extern_dep("rocket", Kind::Static).expect("find core dep")
+    ].join(" "));
+
+    compiletest::run_tests(&config);
+}
+
+#[test]
+fn compile_test() {
+    run_mode("compile-fail");
+    run_mode("ui");
 }

codegen/tests/ui.rs

@@ -1,6 +0,0 @@
-mod compiletest;
-
-#[test]
-fn ui() {
-    compiletest::run(compiletest::Mode::Ui);
-}