feat: clean environment variable

Author: codinaut

Cargo.toml

@@ -8,3 +8,4 @@ edition = "2018"
 
 [dev-dependencies]
 fake = "2.2.3"
+serial_test = "0.4.0"

src/testkit.rs

@@ -1,24 +1,50 @@
 use std::env;
 use std::ffi::{OsStr, OsString};
 
-pub struct EnvironmentTestGuard {}
+pub struct EnvironmentTestGuard {
+    key: OsString,
+}
 
-pub fn set_env<V: AsRef<OsStr>>(key: OsString, value: V) {
-    env::set_var(key, value)
+pub fn set_env<V: AsRef<OsStr>>(key: OsString, value: V) -> EnvironmentTestGuard {
+    env::set_var(&key, value);
+    EnvironmentTestGuard { key }
+}
+
+impl Drop for EnvironmentTestGuard {
+    fn drop(&mut self) {
+        env::remove_var(&self.key)
+    }
 }
 
 #[cfg(test)]
 mod test {
     use super::*;
     use fake::faker::lorem::en::*;
     use fake::Fake;
+    use serial_test::serial;
+
+    fn gen_pair() -> (OsString, OsString) {
+        (
+            OsString::from(Word().fake::<String>()),
+            OsString::from(Sentence(1..10).fake::<String>()),
+        )
+    }
 
     #[test]
+    #[serial]
     fn set_env_ok() {
-        let key = OsString::from(Word().fake::<String>());
-        let value = OsString::from(Sentence(1..10).fake::<String>());
-
-        set_env(key.clone(), &value);
+        let (key, value) = gen_pair();
+        let _e = set_env(key.clone(), &value);
         assert_eq!(env::var_os(key).unwrap(), value)
     }
+
+    #[test]
+    #[serial]
+    fn set_env_clean_up() {
+        let (key, value) = gen_pair();
+        {
+            let _e = set_env(key.clone(), &value);
+        }
+        assert_eq!(env::var_os(key), None)
+    }
 }