Add support for detecting $VIRTUAL_ENV (#181)

Addresses #180

(this is me writing rust for the first time 😬)

Co-authored-by: Don Jayamanne <don.jayamanne@outlook.com>

Author: pantheraleo-7

crates/pet-global-virtualenvs/src/lib.rs

@@ -56,11 +56,20 @@ fn get_global_virtualenv_dirs(
 }
 
 pub fn list_global_virtual_envs_paths(
+    virtual_env_env_var: Option<String>,
     work_on_home_env_var: Option<String>,
     xdg_data_home: Option<String>,
     user_home: Option<PathBuf>,
 ) -> Vec<PathBuf> {
     let mut python_envs: Vec<PathBuf> = vec![];
+
+    if let Some(virtual_env) = virtual_env_env_var {
+        let virtual_env = norm_case(expand_path(PathBuf::from(virtual_env)));
+        if virtual_env.exists() {
+            python_envs.push(virtual_env);
+        }
+    }
+
     for root_dir in &get_global_virtualenv_dirs(work_on_home_env_var, xdg_data_home, user_home) {
         if let Ok(dirs) = fs::read_dir(root_dir) {
             python_envs.append(

crates/pet/src/find.rs

@@ -160,6 +160,7 @@ pub fn find_and_report_envs(
 
                 let search_paths: Vec<PathBuf> = [
                     list_global_virtual_envs_paths(
+                        environment.get_env_var("VIRTUAL_ENV".into()),
                         environment.get_env_var("WORKON_HOME".into()),
                         environment.get_env_var("XDG_DATA_HOME".into()),
                         environment.get_user_home(),