Remove the fixtures directory (#854)

* Empty webpack fixture directories

* Create Fixture struct to kill fixtures dir

* Rename utils mod to fixture mod

* Move cleanup out of preview function

tests/fixture/mod.rs

@@ -0,0 +1,103 @@
+use std::env;
+use std::fs;
+use std::fs::File;
+use std::io::prelude::*;
+use std::path::PathBuf;
+use std::process::Command;
+use std::sync::Mutex;
+
+lazy_static! {
+    static ref BUILD_LOCK: Mutex<u8> = Mutex::new(0);
+}
+
+const BUNDLE_OUT: &str = "./worker";
+
+pub struct Fixture {
+    name: String,
+}
+
+impl Fixture {
+    pub fn new(name: &str) -> Fixture {
+        let fixture = Fixture {
+            name: name.to_string(),
+        };
+
+        let dest = fixture.get_path();
+
+        if dest.exists() {
+            fixture.cleanup();
+        }
+
+        fs::create_dir_all(dest.clone()).unwrap();
+        fixture
+    }
+
+    pub fn scaffold_webpack(&self) {
+        self.create_default_package_json();
+        self.create_empty_js();
+    }
+
+    pub fn get_path(&self) -> PathBuf {
+        let mut dest = env::temp_dir();
+        dest.push(&self.name);
+        dest
+    }
+
+    pub fn get_output_path(&self) -> PathBuf {
+        self.get_path().join(BUNDLE_OUT)
+    }
+
+    pub fn create_file(&self, name: &str, content: &str) {
+        let file_path = self.get_path().join(name);
+        let mut file = File::create(file_path).unwrap();
+        let content = String::from(content);
+        file.write_all(content.as_bytes()).unwrap();
+    }
+
+    pub fn create_dir(&self, name: &str) {
+        let dir_path = self.get_path().join(name);
+        fs::create_dir(dir_path).unwrap();
+    }
+
+    pub fn create_empty_js(&self) {
+        self.create_file("index.js", "");
+    }
+
+    pub fn create_default_package_json(&self) {
+        self.create_file(
+            "package.json",
+            r#"
+            {
+                "main": "index.js"
+            }
+        "#,
+        );
+    }
+
+    pub fn create_wrangler_toml(&self, content: &str) {
+        let content = &format!(
+            r#"
+            name = "test"
+            workers_dev = true
+            {}
+        "#,
+            content
+        );
+        self.create_file("wrangler.toml", content);
+    }
+
+    pub fn cleanup(&self) {
+        let path = self.get_path();
+        assert!(path.exists(), format!("{:?} does not exist", path));
+
+        // Workaround https://github.com/rust-lang/rust/issues/29497
+        if cfg!(target_os = "windows") {
+            let mut command = Command::new("cmd");
+            command.arg("rmdir");
+            command.arg("/s");
+            command.arg(&path);
+        } else {
+            fs::remove_dir_all(&path).unwrap();
+        }
+    }
+}