Setup owns its flow and questions, tested in-process behind a seam

src/command.rs

@@ -14,7 +14,7 @@
 use std::process::ExitCode;
 
 use crate::architect::{self, Reviewed};
-use crate::config::{self, UserConfig};
+use crate::config::UserConfig;
 use crate::failed_run::FailedRun;
 use crate::harness::Choice;
 use crate::interrupt;
@@ -25,6 +25,7 @@ use crate::pickup;
 use crate::progress;
 use crate::run::Ended;
 use crate::run_ending;
+use crate::setup;
 use crate::skills;
 
 /// How a command that did factory work, or was skipped before any, ended.
@@ -92,7 +93,7 @@ pub fn start(
     about: About,
 ) -> Result<(UserConfig, Started), ExitCode> {
     logs::begin(begin);
-    let config = config::offer_setup()
+    let config = setup::offer()
         .and_then(|()| UserConfig::load())
         .map_err(|error| failure(&error))?;
     logs::configured(&config);

src/harness.rs

@@ -320,7 +320,7 @@ impl Catalog {
     }
 
     /// The catalog `codex debug models` printed as `json`.
-    fn parse(json: &str) -> Result<Catalog> {
+    pub fn parse(json: &str) -> Result<Catalog> {
         let parsed: Value = serde_json::from_str(json)
             .context("codex debug models printed no JSON catalog of Models")?;
         let models = parsed["models"]

src/main.rs

@@ -28,12 +28,12 @@ mod progress;
 mod prompt;
 #[cfg(test)]
 mod prompts_page;
-mod questions;
 mod ready;
 mod resend_key;
 mod run;
 mod run_ending;
 mod session;
+mod setup;
 mod skills;
 mod spec_run;
 mod update;
@@ -362,7 +362,7 @@ fn main() -> ExitCode {
             return ExitCode::SUCCESS;
         }
         Ok(Command::Update) => return outcome(update::update()),
-        Ok(Command::Setup) => return outcome(config::setup()),
+        Ok(Command::Setup) => return outcome(setup::setup()),
         Ok(Command::EmailTest(to)) => {
             return outcome(
                 UserConfig::load().and_then(|config| email::send_test(to, &config.email)),

src/resend_key.rs

@@ -24,7 +24,7 @@ pub struct ResendKey {
 }
 
 /// Where a Resend API key came from.
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Debug, Clone, PartialEq, Eq)]
 pub enum Source {
     /// The `RESEND_API_KEY` environment variable.
     Environment,
@@ -284,6 +284,28 @@ mod tests {
         }
     }
 
+    #[test]
+    fn a_saved_key_is_replaced_in_place_keeping_the_rest_of_the_credentials() {
+        let saved = "# My secrets.\n[resend]\n# Rotated monthly.\nkey = \"re_saved_456\"   # from the dashboard\n";
+
+        assert_eq!(
+            with_key(saved, "re_secret_123").unwrap(),
+            "# My secrets.\n[resend]\n# Rotated monthly.\nkey = \"re_secret_123\"   # from the dashboard\n"
+        );
+    }
+
+    #[test]
+    fn a_key_is_added_after_credentials_that_hold_none() {
+        let text = with_key("# Keys go here.\n", "re_secret_123").unwrap();
+
+        assert!(text.starts_with("# Keys go here.\n"), "{text}");
+        let file = Source::Credentials(PathBuf::from("/home/me/.thirdshift/credentials.toml"));
+        assert_eq!(
+            parse(&text, &file).unwrap().as_deref(),
+            Some("re_secret_123")
+        );
+    }
+
     #[test]
     fn broken_credentials_are_an_error_naming_the_file_and_what_is_wrong() {
         let path = "/home/me/.thirdshift/credentials.toml";