Refactor integration tests (#71)

- Create subcommands to be able to print modules independently
	- `starship prompt` will print the full prompt
	- `starship module <MODULE_NAME>` will print a specific module
		e.g. `starship module python`
	- Added `--path` flag to print the prompt or modules without being in a specific directory
	- Added `--status` flag to provide the status of the last command, instead of requiring it as an argument
- Refactored integration tests to be end-to-end tests, since there was no way in integration tests to set the environment variables for a specific command, which was required for the `username` module
- Moved e2e tests to `tests/testsuite` to allow for a single binary to be built
	- Tests will build/run faster
	- No more false positives for unused functions
- Added tests for `username`
- Removed codecov + tarpaulin 😢 

4 files changed, 73 insertions, 17 deletions

diff --git a/src/context.rs b/src/context.rs
index b86bd0708..e0e7e286c 100644
--- a/src/context.rs
+++ b/src/context.rs
@@ -15,11 +15,15 @@ pub struct Context<'a> {
 
 impl<'a> Context<'a> {
     pub fn new(arguments: ArgMatches) -> Context {
-        let current_dir = env::current_dir().expect("Unable to identify current directory.");
-        Context::new_with_dir(arguments, current_dir)
+        // Retreive the "path" flag. If unavailable, use the current directory instead.
+        let path = arguments
+            .value_of("path")
+            .map(From::from)
+            .unwrap_or_else(|| env::current_dir().expect("Unable to identify current directory."));
+
+        Context::new_with_dir(arguments, path)
     }
 
-    #[allow(dead_code)]
     pub fn new_with_dir<T>(arguments: ArgMatches, dir: T) -> Context
     where
         T: Into<PathBuf>,
diff --git a/src/main.rs b/src/main.rs
index 1f69d4ed9..4707cd816 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,36 +1,77 @@
 #[macro_use]
 extern crate clap;
 
-extern crate ansi_term;
-extern crate battery;
-extern crate dirs;
-extern crate git2;
-extern crate pretty_env_logger;
-
 mod context;
 mod module;
 mod modules;
 mod print;
 mod segment;
 
-use clap::{App, Arg};
+use clap::{App, Arg, SubCommand};
 
 fn main() {
     pretty_env_logger::init();
 
-    let args = App::new("Starship")
+    let matches = App::new("Starship")
         .about("The cross-shell prompt for astronauts. ✨🚀")
         // pull the version number from Cargo.toml
         .version(crate_version!())
         // pull the authors from Cargo.toml
         .author(crate_authors!())
         .after_help("https://github.com/matchai/starship")
-        .arg(
-            Arg::with_name("status_code")
-                .help("The status code of the previously run command")
-                .required(true),
+        .subcommand(
+            SubCommand::with_name("prompt")
+                .about("Prints the full starship prompt")
+                .arg(
+                    Arg::with_name("status_code")
+                        .short("s")
+                        .long("status")
+                        .value_name("STATUS_CODE")
+                        .help("The status code of the previously run command")
+                        .takes_value(true),
+                )
+                .arg(
+                    Arg::with_name("path")
+                        .short("p")
+                        .long("path")
+                        .value_name("PATH")
+                        .help("The path that the prompt should render for ($PWD by default)")
+                        .takes_value(true),
+                ),
+        )
+        .subcommand(
+            SubCommand::with_name("module")
+                .about("Prints a specific prompt module")
+                .arg(
+                    Arg::with_name("name")
+                        .help("The name of the module to be printed")
+                        .required(true),
+                )
+                .arg(
+                    Arg::with_name("status_code")
+                        .short("s")
+                        .long("status")
+                        .value_name("STATUS_CODE")
+                        .help("The status code of the previously run command")
+                        .takes_value(true),
+                )
+                .arg(
+                    Arg::with_name("path")
+                        .short("p")
+                        .long("path")
+                        .value_name("PATH")
+                        .help("The path the prompt should render for ($PWD by default)")
+                        .takes_value(true),
+                ),
         )
         .get_matches();
 
-    print::prompt(args);
+    match matches.subcommand() {
+        ("prompt", Some(sub_m)) => print::prompt(sub_m.clone()),
+        ("module", Some(sub_m)) => {
+            let module_name = sub_m.value_of("name").expect("Module name missing.");
+            print::module(module_name, sub_m.clone());
+        }
+        _ => {}
+    }
 }
diff --git a/src/modules/character.rs b/src/modules/character.rs
index 2a9334894..1dfc27991 100644
--- a/src/modules/character.rs
+++ b/src/modules/character.rs
@@ -20,7 +20,7 @@ pub fn segment(context: &Context) -> Option<Module> {
     let symbol = module.new_segment("symbol", PROMPT_CHAR);
 
     let arguments = &context.arguments;
-    if arguments.value_of("status_code").unwrap() == "0" {
+    if arguments.value_of("status_code").unwrap_or("0") == "0" {
         symbol.set_style(color_success.bold());
     } else {
         symbol.set_style(color_failure.bold());
diff --git a/src/print.rs b/src/print.rs
index 53442f23f..71d453e34 100644
--- a/src/print.rs
+++ b/src/print.rs
@@ -46,3 +46,14 @@ pub fn prompt(args: ArgMatches) {
     // Print all remaining modules
     printable.for_each(|module| write!(handle, "{}", module).unwrap());
 }
+
+pub fn module(module_name: &str, args: ArgMatches) {
+    let context = Context::new(args);
+
+    // If the module returns `None`, print an empty string
+    let module = modules::handle(module_name, &context)
+        .map(|m| m.to_string())
+        .unwrap_or_default();
+
+    print!("{}", module);
+}