add version check to the unit tests

clippy_lints/src/utils/cargo.rs

@@ -0,0 +1,75 @@
+use std::collections::HashMap;
+use std::process::Command;
+use std::str::{from_utf8, Utf8Error};
+use std::io;
+use rustc_serialize::json;
+
+#[derive(RustcDecodable, Debug)]
+pub struct Metadata {
+    pub packages: Vec<Package>,
+    resolve: Option<()>,
+    pub version: usize,
+}
+
+#[derive(RustcDecodable, Debug)]
+pub struct Package {
+    pub name: String,
+    pub version: String,
+    id: String,
+    source: Option<()>,
+    pub dependencies: Vec<Dependency>,
+    pub targets: Vec<Target>,
+    features: HashMap<String, Vec<String>>,
+    manifest_path: String,
+}
+
+#[derive(RustcDecodable, Debug)]
+pub struct Dependency {
+    pub name: String,
+    source: Option<String>,
+    pub req: String,
+    kind: Option<String>,
+    optional: bool,
+    uses_default_features: bool,
+    features: Vec<HashMap<String, String>>,
+    target: Option<()>,
+}
+
+#[allow(non_camel_case_types)]
+#[derive(RustcDecodable, Debug)]
+pub enum Kind {
+    dylib,
+    test,
+    bin,
+    lib,
+}
+
+#[derive(RustcDecodable, Debug)]
+pub struct Target {
+    pub name: String,
+    pub kind: Vec<Kind>,
+    src_path: String,
+}
+
+#[derive(Debug)]
+pub enum Error {
+    Io(io::Error),
+    Utf8(Utf8Error),
+    Json(json::DecoderError),
+}
+
+impl From<io::Error> for Error {
+    fn from(err: io::Error) -> Self { Error::Io(err) }
+}
+impl From<Utf8Error> for Error {
+    fn from(err: Utf8Error) -> Self { Error::Utf8(err) }
+}
+impl From<json::DecoderError> for Error {
+    fn from(err: json::DecoderError) -> Self { Error::Json(err) }
+}
+
+pub fn metadata() -> Result<Metadata, Error> {
+    let output = Command::new("cargo").args(&["metadata", "--no-deps"]).output()?;
+    let stdout = from_utf8(&output.stdout)?;
+    Ok(json::decode(stdout)?)
+}

clippy_lints/src/utils/mod.rs

@@ -23,6 +23,7 @@ pub mod conf;
 mod hir;
 pub mod paths;
 pub use self::hir::{SpanlessEq, SpanlessHash};
+pub mod cargo;
 
 pub type MethodArgs = HirVec<P<Expr>>;