Vendor dependencies

Let's see how I like this workflow.

vendor/tokio/tests/fs_dir.rs

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+#![warn(rust_2018_idioms)]
+#![cfg(all(feature = "full", not(tokio_wasi)))] // Wasi does not support directory operations
+
+use tokio::fs;
+use tokio_test::{assert_err, assert_ok};
+
+use std::sync::{Arc, Mutex};
+use tempfile::tempdir;
+
+#[tokio::test]
+async fn create_dir() {
+    let base_dir = tempdir().unwrap();
+    let new_dir = base_dir.path().join("foo");
+    let new_dir_2 = new_dir.clone();
+
+    assert_ok!(fs::create_dir(new_dir).await);
+
+    assert!(new_dir_2.is_dir());
+}
+
+#[tokio::test]
+async fn create_all() {
+    let base_dir = tempdir().unwrap();
+    let new_dir = base_dir.path().join("foo").join("bar");
+    let new_dir_2 = new_dir.clone();
+
+    assert_ok!(fs::create_dir_all(new_dir).await);
+    assert!(new_dir_2.is_dir());
+}
+
+#[tokio::test]
+async fn build_dir() {
+    let base_dir = tempdir().unwrap();
+    let new_dir = base_dir.path().join("foo").join("bar");
+    let new_dir_2 = new_dir.clone();
+
+    assert_ok!(fs::DirBuilder::new().recursive(true).create(new_dir).await);
+
+    assert!(new_dir_2.is_dir());
+    assert_err!(
+        fs::DirBuilder::new()
+            .recursive(false)
+            .create(new_dir_2)
+            .await
+    );
+}
+
+#[tokio::test]
+async fn remove() {
+    let base_dir = tempdir().unwrap();
+    let new_dir = base_dir.path().join("foo");
+    let new_dir_2 = new_dir.clone();
+
+    std::fs::create_dir(new_dir.clone()).unwrap();
+
+    assert_ok!(fs::remove_dir(new_dir).await);
+    assert!(!new_dir_2.exists());
+}
+
+#[tokio::test]
+async fn read_inherent() {
+    let base_dir = tempdir().unwrap();
+
+    let p = base_dir.path();
+    std::fs::create_dir(p.join("aa")).unwrap();
+    std::fs::create_dir(p.join("bb")).unwrap();
+    std::fs::create_dir(p.join("cc")).unwrap();
+
+    let files = Arc::new(Mutex::new(Vec::new()));
+
+    let f = files.clone();
+    let p = p.to_path_buf();
+
+    let mut entries = fs::read_dir(p).await.unwrap();
+
+    while let Some(e) = assert_ok!(entries.next_entry().await) {
+        let s = e.file_name().to_str().unwrap().to_string();
+        f.lock().unwrap().push(s);
+    }
+
+    let mut files = files.lock().unwrap();
+    files.sort(); // because the order is not guaranteed
+    assert_eq!(
+        *files,
+        vec!["aa".to_string(), "bb".to_string(), "cc".to_string()]
+    );
+}