add tests for doctests with cross compilation

Author: Freax13

tests/testsuite/cross_compile.rs

@@ -437,6 +437,42 @@ fn no_cross_doctests() {
         .run();
 }
 
+#[cargo_test]
+fn cross_doctests() {
+    if cross_compile::disabled() || !cross_compile::can_run_on_host() || !is_nightly() {
+        return;
+    }
+
+    let p = project()
+        .file(
+            "src/lib.rs",
+            r#"
+            //! ```
+            //! extern crate foo;
+            //! assert!(true);
+            //! ```
+        "#,
+        )
+        .build();
+
+    let target = cross_compile::alternate();
+
+    // This tests the library and runs the doc tests.
+    p.cargo("test -v -Z doctest-xcompile --target")
+        .arg(&target)
+        .with_stderr(&format!(
+            "\
+[COMPILING] foo v0.0.1 ([CWD])
+[RUNNING] `rustc --crate-name foo [..]--test[..]
+[FINISHED] test [unoptimized + debuginfo] target(s) in [..]
+[RUNNING] `[CWD]/target/{triple}/debug/deps/foo-[..][EXE]`
+[DOCTEST] foo
+",
+            triple = target
+        ))
+        .run();
+}
+
 #[cargo_test]
 fn simple_cargo_run() {
     if !cross_compile::can_run_on_host() {