use std::env;
use std::path::PathBuf;
const SLATE_FILEPATH: &'static str = "SLATE_FILEPATH";
pub trait EnvWrapper {
fn var(&self, var: &'static str) -> Result<String, env::VarError>;
}
struct Env;
impl EnvWrapper for Env {
fn var(&self, var: &'static str) -> Result<String, env::VarError> {
env::var(var)
}
}
#[derive(Clone)]
pub struct Config {
pub filepath: PathBuf,
}
impl Config {
pub fn from_env() -> Config {
let wrapper = Env;
Self::new(wrapper)
}
pub fn new<T: EnvWrapper>(wrapper: T) -> Config {
let config: Config = match wrapper.var(SLATE_FILEPATH) {
Ok(value) => Config { filepath: PathBuf::from(value) },
Err(_) => Default::default(),
};
config
}
}
impl Default for Config {
fn default() -> Config {
let mut path = match env::home_dir() {
Some(home) => home,
None => panic!("No HOME dir found"),
};
path.push(".slate");
Config { filepath: path }
}
}
#[cfg(test)]
mod tests {
use super::*;
use std::env;
use std::path::PathBuf;
struct MockEnv {
value: Option<bool>,
}
impl EnvWrapper for MockEnv {
fn var(&self, _var: &'static str) -> Result<String, env::VarError> {
match self.value {
Some(_) => Ok("/tmp/slate".to_string()),
None => Err(env::VarError::NotPresent)
}
}
}
#[test]
fn it_uses_the_homedir_as_default_path() {
let wrapper = MockEnv { value: None };
let config: Config = Config::new(wrapper);
let mut expected: PathBuf = env::home_dir().unwrap();
expected.push(".slate");
assert_eq!(expected, config.filepath);
}
#[test]
fn it_uses_the_environment_var_if_set() {
let wrapper = MockEnv { value: Some(true) };
let config: Config = Config::new(wrapper);
let expected: PathBuf = PathBuf::from("/tmp/slate");
assert_eq!(expected, config.filepath);
}
}