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 😢 

1 files changed, 11 insertions, 0 deletions

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);
+}