Enable tests that depend on bincodeHEADmastermain

The bincode crate was imported in b/330683225, so we can now enable
unit tests for crates which uses it as a dev-dependency.

This change includes a patch submitted upstream:
https://github.com/rust-vmm/vmm-sys-util/pull/221.

Bug: 333560480
Flag: TEST_ONLY
Test: atest --host vmm-sys-util_test_src_lib
Change-Id: Id2f7fdd8bee8a313ed09ff19028aa63e1cfde0e7

3 files changed, 33 insertions, 6 deletions

diff --git a/Android.bp b/Android.bp
index b25068f..59aa814 100644
--- a/Android.bp
+++ b/Android.bp
@@ -1,5 +1,7 @@
 // This file is generated by cargo_embargo.
-// Do not modify this file as changes will be overridden on upgrade.
+// Do not modify this file after the first "rust_*" or "genrule" module
+// because the changes will be overridden on upgrade.
+// Content before the first "rust_*" or "genrule" module is preserved.
 
 rust_library_host {
     name: "libvmm_sys_util",
@@ -13,3 +15,23 @@ rust_library_host {
         "liblibc",
     ],
 }
+
+rust_test_host {
+    name: "vmm-sys-util_test_src_lib",
+    crate_name: "vmm_sys_util",
+    cargo_env_compat: true,
+    cargo_pkg_version: "0.12.1",
+    srcs: ["src/lib.rs"],
+    test_suites: ["general-tests"],
+    auto_gen_config: true,
+    test_options: {
+        unit_test: true,
+    },
+    edition: "2021",
+    rustlibs: [
+        "libbincode",
+        "libbitflags-1.3.2",
+        "liblibc",
+        "libserde_json",
+    ],
+}
diff --git a/cargo_embargo.json b/cargo_embargo.json
index bc1c4ce..4ba71a8 100644
--- a/cargo_embargo.json
+++ b/cargo_embargo.json
@@ -7,5 +7,6 @@
       "device_supported": false
     }
   },
-  "run_cargo": false
+  "run_cargo": false,
+  "tests": true
 }
diff --git a/src/errno.rs b/src/errno.rs
index 27b9bcf..3478b7c 100644
--- a/src/errno.rs
+++ b/src/errno.rs
@@ -132,7 +132,7 @@ pub fn errno_result<T>() -> Result<T> {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use std::env::temp_dir;
+    use crate::tempfile::TempFile;
     use std::error::Error as _;
     use std::fs::OpenOptions;
     use std::io::{self, Read};
@@ -145,14 +145,16 @@ mod tests {
         let expected_errno = libc::EIO;
 
         // try to read from a file without read permissions
-        let mut path = temp_dir();
-        path.push("test");
+        let temp_file = TempFile::new().unwrap();
+        let path = temp_file.as_path().to_owned();
+        // Drop temp_file so we can cleanly reuse path below.
+        std::mem::drop(temp_file);
         let mut file = OpenOptions::new()
             .read(false)
             .write(true)
             .create(true)
             .truncate(true)
-            .open(path)
+            .open(&path)
             .unwrap();
         let mut buf: Vec<u8> = Vec::new();
         assert!(file.read_to_end(&mut buf).is_err());
@@ -174,6 +176,8 @@ mod tests {
         let last_err: io::Error = last_err.into();
         // Test creating a `std::io::Error` from an `Error`
         assert_eq!(io::Error::last_os_error().kind(), last_err.kind());
+
+        assert!(std::fs::remove_file(&path).is_ok());
     }
 
     #[test]