Fixing and stabilizing github actions (#275)

* add a necessary dependencie.

* remove a unnecessary step in ci.

* stabilize unstable tests by making them serial.

.github/workflows/main.yml

@@ -45,7 +45,7 @@ jobs:
           override: true
       - run: rustup component add rustfmt clippy
       - run: sudo apt-get -y update
-      - run: sudo apt-get install -y pkg-config libsystemd-dev libdbus-glib-1-dev
+      - run: sudo apt-get install -y pkg-config libsystemd-dev libdbus-glib-1-dev libelf-dev
       - name: Check formatting
         run: cargo fmt --all -- --check
         working-directory: ${{matrix.dirs}}
@@ -74,8 +74,6 @@ jobs:
           override: true
       - run: sudo apt-get -y update
       - run: sudo apt-get install -y pkg-config libsystemd-dev libdbus-glib-1-dev libelf-dev
-      - name: Build
-        run: ./build.sh --release
       - name: Run tests
         run: cargo test --no-fail-fast
       - name: Run doc tests

src/process/init.rs

@@ -567,6 +567,7 @@ mod tests {
     use super::*;
     use anyhow::{bail, Result};
     use nix::{fcntl, sys, unistd};
+    use serial_test::serial;
     use std::fs;
 
     #[test]
@@ -594,6 +595,7 @@ mod tests {
     }
 
     #[test]
+    #[serial]
     fn test_cleanup_file_descriptors() -> Result<()> {
         // Open a fd without the CLOEXEC flag. Rust automatically adds the flag,
         // so we use fcntl::open here for more control.