1 files changed, 98 insertions, 0 deletions
diff --git a/third_party/rust/failure_derive/tests/wraps.rs b/third_party/rust/failure_derive/tests/wraps.rs
new file mode 100644
index 0000000000..9144325cad
--- /dev/null
+++ b/third_party/rust/failure_derive/tests/wraps.rs
@@ -0,0 +1,98 @@
+extern crate failure;
+#[macro_use]
+extern crate failure_derive;
+
+use std::fmt;
+use std::io;
+
+use failure::{Backtrace, Fail};
+
+#[derive(Fail, Debug)]
+#[fail(display = "An error has occurred: {}", inner)]
+struct WrapError {
+    #[fail(cause)]
+    inner: io::Error,
+}
+
+#[test]
+fn wrap_error() {
+    let inner = io::Error::from_raw_os_error(98);
+    let err = WrapError { inner };
+    assert!(err
+        .cause()
+        .and_then(|err| err.downcast_ref::<io::Error>())
+        .is_some());
+}
+
+#[derive(Fail, Debug)]
+#[fail(display = "An error has occurred: {}", _0)]
+struct WrapTupleError(#[fail(cause)] io::Error);
+
+#[test]
+fn wrap_tuple_error() {
+    let io_error = io::Error::from_raw_os_error(98);
+    let err: WrapTupleError = WrapTupleError(io_error);
+    assert!(err
+        .cause()
+        .and_then(|err| err.downcast_ref::<io::Error>())
+        .is_some());
+}
+
+#[derive(Fail, Debug)]
+#[fail(display = "An error has occurred: {}", inner)]
+struct WrapBacktraceError {
+    #[fail(cause)]
+    inner: io::Error,
+    backtrace: Backtrace,
+}
+
+#[test]
+fn wrap_backtrace_error() {
+    let inner = io::Error::from_raw_os_error(98);
+    let err: WrapBacktraceError = WrapBacktraceError {
+        inner,
+        backtrace: Backtrace::new(),
+    };
+    assert!(err
+        .cause()
+        .and_then(|err| err.downcast_ref::<io::Error>())
+        .is_some());
+    assert!(err.backtrace().is_some());
+    assert!(err.backtrace().unwrap().is_empty());
+    assert!(err.backtrace().unwrap().to_string().trim().is_empty());
+}
+
+#[derive(Fail, Debug)]
+enum WrapEnumError {
+    #[fail(display = "An error has occurred: {}", _0)]
+    Io(#[fail(cause)] io::Error),
+    #[fail(display = "An error has occurred: {}", inner)]
+    Fmt {
+        #[fail(cause)]
+        inner: fmt::Error,
+        backtrace: Backtrace,
+    },
+}
+
+#[test]
+fn wrap_enum_error() {
+    let io_error = io::Error::from_raw_os_error(98);
+    let err: WrapEnumError = WrapEnumError::Io(io_error);
+    assert!(err
+        .cause()
+        .and_then(|err| err.downcast_ref::<io::Error>())
+        .is_some());
+    assert!(err.backtrace().is_none());
+    let fmt_error = fmt::Error::default();
+    let err: WrapEnumError = WrapEnumError::Fmt {
+        inner: fmt_error,
+        backtrace: Backtrace::new(),
+    };
+    assert!(err
+        .cause()
+        .and_then(|err| err.downcast_ref::<fmt::Error>())
+        .is_some());
+    assert!(err.backtrace().is_some());
+    assert!(err.backtrace().unwrap().is_empty());
+    assert!(err.backtrace().unwrap().to_string().trim().is_empty());
+}