Support Rust dependencies

tests/samples/codefiles/rust.rs

@@ -0,0 +1,21 @@
+extern crate proc_macro;
+extern crate phrases as sayings;
+extern crate syn;
+#[macro_use]
+extern crate quote;
+
+use sayings::japanese::greetings as ja_greetings;
+use sayings::japanese::farewells::*;
+use sayings::english::{self, greetings as en_greetings, farewells as en_farewells};
+
+extern "C" {
+    fn c_callback(n: c_int);
+}
+
+fn main() {
+    println!("Hello in English; {}", en_greetings::hello());
+    println!("And in Japanese: {}", ja_greetings::hello());
+    println!("Goodbye in English: {}", english::farewells::goodbye());
+    println!("Again: {}", en_farewells::goodbye());
+    println!("And in Japanese: {}", goodbye());
+}

tests/test_dependencies.py

@@ -435,3 +435,16 @@ class DependenciesTestCase(TestCase):
             expected_lines=14,
             entity='scala.scala',
         )
+
+    def test_rust_dependencies_detected(self):
+        self.shared(
+            expected_dependencies=[
+                'proc_macro',
+                'phrases',
+                'syn',
+                'quote',
+            ],
+            expected_language='Rust',
+            expected_lines=21,
+            entity='rust.rs',
+        )