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, 1 insertions, 1 deletions

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());