test: add comprehensive unit test suite (~85 new tests)

Add unit tests across all model and server infrastructure layers,
increasing test count from 7 to 92. Covers serde round-trips, enum
methods, defaults, config parsing, error mapping, PKCE crypto (with
RFC 7636 test vector), OAuth store, and SearXNG ranking/dedup logic.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Cargo.lock

@@ -776,6 +776,7 @@ dependencies = [
  "maud",
  "mongodb",
  "petname",
+ "pretty_assertions",
  "pulldown-cmark",
  "rand 0.10.0",
  "reqwest 0.13.2",
@@ -783,6 +784,7 @@ dependencies = [
  "secrecy",
  "serde",
  "serde_json",
+ "serial_test",
  "sha2",
  "thiserror 2.0.18",
  "time",
@@ -882,6 +884,12 @@ dependencies = [
  "unicode-xid",
 ]
 
+[[package]]
+name = "diff"
+version = "0.1.13"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "56254986775e3233ffa9c4d7d3faaf6d36a2c09d30b20687e9f88bc8bafc16c8"
+
 [[package]]
 name = "digest"
 version = "0.10.7"
@@ -3246,6 +3254,16 @@ version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "925383efa346730478fb4838dbe9137d2a47675ad789c546d150a6e1dd4ab31c"
 
+[[package]]
+name = "pretty_assertions"
+version = "1.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3ae130e2f271fbc2ac3a40fb1d07180839cdbbe443c7a27e1e3c13c5cac0116d"
+dependencies = [
+ "diff",
+ "yansi",
+]
+
 [[package]]
 name = "prettyplease"
 version = "0.2.37"
@@ -3823,6 +3841,15 @@ dependencies = [
  "winapi-util",
 ]
 
+[[package]]
+name = "scc"
+version = "2.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "46e6f046b7fef48e2660c57ed794263155d713de679057f2d0c169bfc6e756cc"
+dependencies = [
+ "sdd",
+]
+
 [[package]]
 name = "schannel"
 version = "0.1.28"
@@ -3862,6 +3889,12 @@ dependencies = [
  "untrusted",
 ]
 
+[[package]]
+name = "sdd"
+version = "3.0.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "490dcfcbfef26be6800d11870ff2df8774fa6e86d047e3e8c8a76b25655e41ca"
+
 [[package]]
 name = "secrecy"
 version = "0.10.3"
@@ -4082,6 +4115,32 @@ dependencies = [
  "syn 2.0.116",
 ]
 
+[[package]]
+name = "serial_test"
+version = "3.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "911bd979bf1070a3f3aa7b691a3b3e9968f339ceeec89e08c280a8a22207a32f"
+dependencies = [
+ "futures-executor",
+ "futures-util",
+ "log",
+ "once_cell",
+ "parking_lot",
+ "scc",
+ "serial_test_derive",
+]
+
+[[package]]
+name = "serial_test_derive"
+version = "3.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0a7d91949b85b0d2fb687445e448b40d322b6b3e4af6b44a29b21d9a5f33e6d9"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.116",
+]
+
 [[package]]
 name = "servo_arc"
 version = "0.4.3"
@@ -5683,6 +5742,12 @@ version = "0.8.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fdd20c5420375476fbd4394763288da7eb0cc0b8c11deed431a91562af7335d3"
 
+[[package]]
+name = "yansi"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cfe53a6657fd280eaa890a3bc59152892ffa3e30101319d168b781ed6529b049"
+
 [[package]]
 name = "yazi"
 version = "0.1.6"

Cargo.toml

@@ -112,6 +112,10 @@ server = [
     "dep:bytes",
 ]
 
+[dev-dependencies]
+pretty_assertions = "1.4"
+serial_test = "3.2"
+
 [[bin]]
 name = "dashboard"
 path = "bin/main.rs"

src/infrastructure/auth.rs

@@ -24,9 +24,9 @@ pub const LOGGED_IN_USER_SESS_KEY: &str = "logged-in-user";
 /// post-login redirect URL and the PKCE code verifier needed for the
 /// token exchange.
 #[derive(Debug, Clone)]
-struct PendingOAuthEntry {
+pub(crate) struct PendingOAuthEntry {
-    redirect_url: Option<String>,
+    pub(crate) redirect_url: Option<String>,
-    code_verifier: String,
+    pub(crate) code_verifier: String,
 }
 
 /// In-memory store for pending OAuth states. Keyed by the random state
@@ -38,7 +38,7 @@ pub struct PendingOAuthStore(Arc<RwLock<HashMap<String, PendingOAuthEntry>>>);
 
 impl PendingOAuthStore {
     /// Insert a pending state with an optional redirect URL and PKCE verifier.
-    fn insert(&self, state: String, entry: PendingOAuthEntry) {
+    pub(crate) fn insert(&self, state: String, entry: PendingOAuthEntry) {
         // RwLock::write only panics if the lock is poisoned, which
         // indicates a prior panic -- propagating is acceptable here.
         #[allow(clippy::expect_used)]
@@ -50,7 +50,7 @@ impl PendingOAuthStore {
 
     /// Remove and return the entry if the state was pending.
     /// Returns `None` if the state was never stored (CSRF failure).
-    fn take(&self, state: &str) -> Option<PendingOAuthEntry> {
+    pub(crate) fn take(&self, state: &str) -> Option<PendingOAuthEntry> {
         #[allow(clippy::expect_used)]
         self.0
             .write()
@@ -60,7 +60,8 @@ impl PendingOAuthStore {
 }
 
 /// Generate a cryptographically random state string for CSRF protection.
-fn generate_state() -> String {
+#[cfg_attr(test, allow(dead_code))]
+pub(crate) fn generate_state() -> String {
     let bytes: [u8; 32] = rand::rng().random();
     // Encode as hex to produce a URL-safe string without padding.
     bytes.iter().fold(String::with_capacity(64), |mut acc, b| {
@@ -75,7 +76,7 @@ fn generate_state() -> String {
 ///
 /// Uses 32 random bytes encoded as base64url (no padding) to produce
 /// a 43-character verifier per RFC 7636.
-fn generate_code_verifier() -> String {
+pub(crate) fn generate_code_verifier() -> String {
     use base64::{engine::general_purpose::URL_SAFE_NO_PAD, Engine};
 
     let bytes: [u8; 32] = rand::rng().random();
@@ -85,7 +86,7 @@ fn generate_code_verifier() -> String {
 /// Derive the S256 code challenge from a code verifier per RFC 7636.
 ///
 /// `code_challenge = BASE64URL(SHA256(code_verifier))`
-fn derive_code_challenge(verifier: &str) -> String {
+pub(crate) fn derive_code_challenge(verifier: &str) -> String {
     use base64::{engine::general_purpose::URL_SAFE_NO_PAD, Engine};
     use sha2::{Digest, Sha256};
 
@@ -304,3 +305,117 @@ pub async fn set_login_session(session: Session, data: UserStateInner) -> Result
         .await
         .map_err(|e| Error::StateError(format!("session insert failed: {e}")))
 }
+
+#[cfg(test)]
+mod tests {
+    #![allow(clippy::unwrap_used, clippy::expect_used)]
+
+    use super::*;
+    use pretty_assertions::assert_eq;
+
+    // -----------------------------------------------------------------------
+    // generate_state()
+    // -----------------------------------------------------------------------
+
+    #[test]
+    fn generate_state_length_is_64() {
+        let state = generate_state();
+        assert_eq!(state.len(), 64);
+    }
+
+    #[test]
+    fn generate_state_chars_are_hex() {
+        let state = generate_state();
+        assert!(state.chars().all(|c| c.is_ascii_hexdigit()));
+    }
+
+    #[test]
+    fn generate_state_two_calls_differ() {
+        let a = generate_state();
+        let b = generate_state();
+        assert_ne!(a, b);
+    }
+
+    // -----------------------------------------------------------------------
+    // generate_code_verifier()
+    // -----------------------------------------------------------------------
+
+    #[test]
+    fn code_verifier_length_is_43() {
+        let verifier = generate_code_verifier();
+        assert_eq!(verifier.len(), 43);
+    }
+
+    #[test]
+    fn code_verifier_chars_are_url_safe_base64() {
+        let verifier = generate_code_verifier();
+        // URL-safe base64 without padding uses [A-Za-z0-9_-]
+        assert!(verifier
+            .chars()
+            .all(|c| c.is_ascii_alphanumeric() || c == '-' || c == '_'));
+    }
+
+    // -----------------------------------------------------------------------
+    // derive_code_challenge()
+    // -----------------------------------------------------------------------
+
+    #[test]
+    fn code_challenge_deterministic() {
+        let verifier = "dBjftJeZ4CVP-mB92K27uhbUJU1p1r_wW1gFWFOEjXk";
+        let a = derive_code_challenge(verifier);
+        let b = derive_code_challenge(verifier);
+        assert_eq!(a, b);
+    }
+
+    #[test]
+    fn code_challenge_rfc7636_test_vector() {
+        // RFC 7636 Appendix B test vector:
+        // verifier = "dBjftJeZ4CVP-mB92K27uhbUJU1p1r_wW1gFWFOEjXk"
+        // expected challenge = "E9Melhoa2OwvFrEMTJguCHaoeK1t8URWbuGJSstw-cM"
+        let verifier = "dBjftJeZ4CVP-mB92K27uhbUJU1p1r_wW1gFWFOEjXk";
+        let challenge = derive_code_challenge(verifier);
+        assert_eq!(challenge, "E9Melhoa2OwvFrEMTJguCHaoeK1t8URWbuGJSstw-cM");
+    }
+
+    // -----------------------------------------------------------------------
+    // PendingOAuthStore
+    // -----------------------------------------------------------------------
+
+    #[test]
+    fn pending_store_insert_and_take() {
+        let store = PendingOAuthStore::default();
+        store.insert(
+            "state-1".into(),
+            PendingOAuthEntry {
+                redirect_url: Some("/dashboard".into()),
+                code_verifier: "verifier-1".into(),
+            },
+        );
+        let entry = store.take("state-1");
+        assert!(entry.is_some());
+        let entry = entry.unwrap();
+        assert_eq!(entry.redirect_url, Some("/dashboard".into()));
+        assert_eq!(entry.code_verifier, "verifier-1");
+    }
+
+    #[test]
+    fn pending_store_take_removes_entry() {
+        let store = PendingOAuthStore::default();
+        store.insert(
+            "state-2".into(),
+            PendingOAuthEntry {
+                redirect_url: None,
+                code_verifier: "v2".into(),
+            },
+        );
+        let _ = store.take("state-2");
+        // Second take should return None since the entry was removed.
+        assert!(store.take("state-2").is_none());
+    }
+
+    #[test]
+    fn pending_store_take_unknown_returns_none() {
+        let store = PendingOAuthStore::default();
+        assert!(store.take("nonexistent").is_none());
+    }
+}

src/infrastructure/config.rs

@@ -251,3 +251,160 @@ impl LlmProvidersConfig {
         Ok(Self { providers })
     }
 }
+
+#[cfg(test)]
+mod tests {
+    #![allow(clippy::unwrap_used, clippy::expect_used)]
+
+    use super::*;
+    use pretty_assertions::assert_eq;
+    use serial_test::serial;
+
+    // -----------------------------------------------------------------------
+    // KeycloakConfig endpoint methods (no env vars needed)
+    // -----------------------------------------------------------------------
+
+    fn sample_keycloak() -> KeycloakConfig {
+        KeycloakConfig {
+            url: "https://auth.example.com".into(),
+            realm: "myrealm".into(),
+            client_id: "dashboard".into(),
+            redirect_uri: "https://app.example.com/callback".into(),
+            app_url: "https://app.example.com".into(),
+            admin_client_id: String::new(),
+            admin_client_secret: SecretString::from(String::new()),
+        }
+    }
+
+    #[test]
+    fn keycloak_auth_endpoint() {
+        let kc = sample_keycloak();
+        assert_eq!(
+            kc.auth_endpoint(),
+            "https://auth.example.com/realms/myrealm/protocol/openid-connect/auth"
+        );
+    }
+
+    #[test]
+    fn keycloak_token_endpoint() {
+        let kc = sample_keycloak();
+        assert_eq!(
+            kc.token_endpoint(),
+            "https://auth.example.com/realms/myrealm/protocol/openid-connect/token"
+        );
+    }
+
+    #[test]
+    fn keycloak_userinfo_endpoint() {
+        let kc = sample_keycloak();
+        assert_eq!(
+            kc.userinfo_endpoint(),
+            "https://auth.example.com/realms/myrealm/protocol/openid-connect/userinfo"
+        );
+    }
+
+    #[test]
+    fn keycloak_logout_endpoint() {
+        let kc = sample_keycloak();
+        assert_eq!(
+            kc.logout_endpoint(),
+            "https://auth.example.com/realms/myrealm/protocol/openid-connect/logout"
+        );
+    }
+
+    // -----------------------------------------------------------------------
+    // LlmProvidersConfig::from_env()
+    // -----------------------------------------------------------------------
+
+    #[test]
+    #[serial]
+    fn llm_providers_empty_string() {
+        std::env::set_var("LLM_PROVIDERS", "");
+        let cfg = LlmProvidersConfig::from_env().unwrap();
+        assert!(cfg.providers.is_empty());
+        std::env::remove_var("LLM_PROVIDERS");
+    }
+
+    #[test]
+    #[serial]
+    fn llm_providers_single() {
+        std::env::set_var("LLM_PROVIDERS", "ollama");
+        let cfg = LlmProvidersConfig::from_env().unwrap();
+        assert_eq!(cfg.providers, vec!["ollama"]);
+        std::env::remove_var("LLM_PROVIDERS");
+    }
+
+    #[test]
+    #[serial]
+    fn llm_providers_multiple() {
+        std::env::set_var("LLM_PROVIDERS", "ollama,openai,anthropic");
+        let cfg = LlmProvidersConfig::from_env().unwrap();
+        assert_eq!(cfg.providers, vec!["ollama", "openai", "anthropic"]);
+        std::env::remove_var("LLM_PROVIDERS");
+    }
+
+    #[test]
+    #[serial]
+    fn llm_providers_trims_whitespace() {
+        std::env::set_var("LLM_PROVIDERS", " ollama , openai ");
+        let cfg = LlmProvidersConfig::from_env().unwrap();
+        assert_eq!(cfg.providers, vec!["ollama", "openai"]);
+        std::env::remove_var("LLM_PROVIDERS");
+    }
+
+    #[test]
+    #[serial]
+    fn llm_providers_filters_empty_entries() {
+        std::env::set_var("LLM_PROVIDERS", "ollama,,openai,");
+        let cfg = LlmProvidersConfig::from_env().unwrap();
+        assert_eq!(cfg.providers, vec!["ollama", "openai"]);
+        std::env::remove_var("LLM_PROVIDERS");
+    }
+
+    // -----------------------------------------------------------------------
+    // ServiceUrls::from_env() defaults
+    // -----------------------------------------------------------------------
+
+    #[test]
+    #[serial]
+    fn service_urls_default_ollama_url() {
+        std::env::remove_var("OLLAMA_URL");
+        let svc = ServiceUrls::from_env().unwrap();
+        assert_eq!(svc.ollama_url, "http://localhost:11434");
+    }
+
+    #[test]
+    #[serial]
+    fn service_urls_default_ollama_model() {
+        std::env::remove_var("OLLAMA_MODEL");
+        let svc = ServiceUrls::from_env().unwrap();
+        assert_eq!(svc.ollama_model, "llama3.1:8b");
+    }
+
+    #[test]
+    #[serial]
+    fn service_urls_default_searxng_url() {
+        std::env::remove_var("SEARXNG_URL");
+        let svc = ServiceUrls::from_env().unwrap();
+        assert_eq!(svc.searxng_url, "http://localhost:8888");
+    }
+
+    #[test]
+    #[serial]
+    fn service_urls_custom_ollama_url() {
+        std::env::set_var("OLLAMA_URL", "http://gpu-host:11434");
+        let svc = ServiceUrls::from_env().unwrap();
+        assert_eq!(svc.ollama_url, "http://gpu-host:11434");
+        std::env::remove_var("OLLAMA_URL");
+    }
+
+    #[test]
+    #[serial]
+    fn required_env_missing_returns_config_error() {
+        std::env::remove_var("__TEST_REQUIRED_MISSING__");
+        let result = required_env("__TEST_REQUIRED_MISSING__");
+        assert!(result.is_err());
+        let err_msg = result.unwrap_err().to_string();
+        assert!(err_msg.contains("__TEST_REQUIRED_MISSING__"));
+    }
+}

src/infrastructure/error.rs

@@ -41,3 +41,53 @@ impl IntoResponse for Error {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use axum::response::IntoResponse;
+    use pretty_assertions::assert_eq;
+
+    #[test]
+    fn state_error_display() {
+        let err = Error::StateError("bad state".into());
+        assert_eq!(err.to_string(), "bad state");
+    }
+
+    #[test]
+    fn database_error_display() {
+        let err = Error::DatabaseError("connection lost".into());
+        assert_eq!(err.to_string(), "database error: connection lost");
+    }
+
+    #[test]
+    fn config_error_display() {
+        let err = Error::ConfigError("missing var".into());
+        assert_eq!(err.to_string(), "configuration error: missing var");
+    }
+
+    #[test]
+    fn state_error_into_response_500() {
+        let resp = Error::StateError("oops".into()).into_response();
+        assert_eq!(resp.status(), StatusCode::INTERNAL_SERVER_ERROR);
+    }
+
+    #[test]
+    fn database_error_into_response_503() {
+        let resp = Error::DatabaseError("down".into()).into_response();
+        assert_eq!(resp.status(), StatusCode::SERVICE_UNAVAILABLE);
+    }
+
+    #[test]
+    fn config_error_into_response_500() {
+        let resp = Error::ConfigError("bad cfg".into()).into_response();
+        assert_eq!(resp.status(), StatusCode::INTERNAL_SERVER_ERROR);
+    }
+
+    #[test]
+    fn io_error_into_response_500() {
+        let io_err = std::io::Error::new(std::io::ErrorKind::NotFound, "not found");
+        let resp = Error::IoError(io_err).into_response();
+        assert_eq!(resp.status(), StatusCode::INTERNAL_SERVER_ERROR);
+    }
+}

src/infrastructure/searxng.rs

@@ -5,13 +5,13 @@ use dioxus::prelude::*;
 // The #[server] macro generates a client stub for the web build that
 // sends a network request instead of executing this function body.
 #[cfg(feature = "server")]
-mod inner {
+pub(crate) mod inner {
     use serde::Deserialize;
     use std::collections::HashSet;
 
     /// Individual result from the SearXNG search API.
     #[derive(Debug, Deserialize)]
-    pub(super) struct SearxngResult {
+    pub(crate) struct SearxngResult {
         pub title: String,
         pub url: String,
         pub content: Option<String>,
@@ -25,7 +25,7 @@ mod inner {
 
     /// Top-level response from the SearXNG search API.
     #[derive(Debug, Deserialize)]
-    pub(super) struct SearxngResponse {
+    pub(crate) struct SearxngResponse {
         pub results: Vec<SearxngResult>,
     }
 
@@ -40,7 +40,7 @@ mod inner {
     /// # Returns
     ///
     /// The domain host or a fallback "Web" string
-    pub(super) fn extract_source(url_str: &str) -> String {
+    pub(crate) fn extract_source(url_str: &str) -> String {
         url::Url::parse(url_str)
             .ok()
             .and_then(|u| u.host_str().map(String::from))
@@ -64,7 +64,7 @@ mod inner {
     /// # Returns
     ///
     /// Filtered, deduplicated, and ranked results
-    pub(super) fn rank_and_deduplicate(
+    pub(crate) fn rank_and_deduplicate(
         mut results: Vec<SearxngResult>,
         max_results: usize,
     ) -> Vec<SearxngResult> {
@@ -285,3 +285,166 @@ pub async fn get_trending_topics() -> Result<Vec<String>, ServerFnError> {
 
     Ok(topics)
 }
+
+#[cfg(all(test, feature = "server"))]
+mod tests {
+    #![allow(clippy::unwrap_used, clippy::expect_used)]
+
+    use super::inner::*;
+    use pretty_assertions::assert_eq;
+
+    // -----------------------------------------------------------------------
+    // extract_source()
+    // -----------------------------------------------------------------------
+
+    #[test]
+    fn extract_source_strips_www() {
+        assert_eq!(
+            extract_source("https://www.example.com/page"),
+            "example.com"
+        );
+    }
+
+    #[test]
+    fn extract_source_returns_domain() {
+        assert_eq!(
+            extract_source("https://techcrunch.com/article"),
+            "techcrunch.com"
+        );
+    }
+
+    #[test]
+    fn extract_source_invalid_url_returns_web() {
+        assert_eq!(extract_source("not-a-url"), "Web");
+    }
+
+    #[test]
+    fn extract_source_no_scheme_returns_web() {
+        // url::Url::parse requires a scheme; bare domain fails
+        assert_eq!(extract_source("example.com/path"), "Web");
+    }
+
+    // -----------------------------------------------------------------------
+    // rank_and_deduplicate()
+    // -----------------------------------------------------------------------
+
+    fn make_result(url: &str, content: &str, score: f64) -> SearxngResult {
+        SearxngResult {
+            title: "Title".into(),
+            url: url.into(),
+            content: if content.is_empty() {
+                None
+            } else {
+                Some(content.into())
+            },
+            published_date: None,
+            thumbnail: None,
+            score,
+        }
+    }
+
+    #[test]
+    fn rank_filters_empty_content() {
+        let results = vec![
+            make_result("https://a.com", "", 10.0),
+            make_result(
+                "https://b.com",
+                "This is meaningful content that passes the length filter",
+                5.0,
+            ),
+        ];
+        let ranked = rank_and_deduplicate(results, 10);
+        assert_eq!(ranked.len(), 1);
+        assert_eq!(ranked[0].url, "https://b.com");
+    }
+
+    #[test]
+    fn rank_filters_short_content() {
+        let results = vec![
+            make_result("https://a.com", "short", 10.0),
+            make_result(
+                "https://b.com",
+                "This content is long enough to pass the 20-char filter threshold",
+                5.0,
+            ),
+        ];
+        let ranked = rank_and_deduplicate(results, 10);
+        assert_eq!(ranked.len(), 1);
+    }
+
+    #[test]
+    fn rank_deduplicates_by_domain_keeps_highest() {
+        let results = vec![
+            make_result(
+                "https://example.com/page1",
+                "First result with enough content here for the filter",
+                3.0,
+            ),
+            make_result(
+                "https://example.com/page2",
+                "Second result with enough content here for the filter",
+                8.0,
+            ),
+        ];
+        let ranked = rank_and_deduplicate(results, 10);
+        assert_eq!(ranked.len(), 1);
+        // Should keep the highest-scored one (page2 with score 8.0)
+        assert_eq!(ranked[0].url, "https://example.com/page2");
+    }
+
+    #[test]
+    fn rank_sorts_by_score_descending() {
+        let results = vec![
+            make_result(
+                "https://a.com/p",
+                "Content A that is long enough to pass the filter check",
+                1.0,
+            ),
+            make_result(
+                "https://b.com/p",
+                "Content B that is long enough to pass the filter check",
+                5.0,
+            ),
+            make_result(
+                "https://c.com/p",
+                "Content C that is long enough to pass the filter check",
+                3.0,
+            ),
+        ];
+        let ranked = rank_and_deduplicate(results, 10);
+        assert_eq!(ranked.len(), 3);
+        assert!(ranked[0].score >= ranked[1].score);
+        assert!(ranked[1].score >= ranked[2].score);
+    }
+
+    #[test]
+    fn rank_truncates_to_max_results() {
+        let results: Vec<_> = (0..20)
+            .map(|i| {
+                make_result(
+                    &format!("https://site{i}.com/page"),
+                    &format!("Content for site {i} that is long enough to pass the filter"),
+                    i as f64,
+                )
+            })
+            .collect();
+        let ranked = rank_and_deduplicate(results, 5);
+        assert_eq!(ranked.len(), 5);
+    }
+
+    #[test]
+    fn rank_empty_input_returns_empty() {
+        let ranked = rank_and_deduplicate(vec![], 10);
+        assert!(ranked.is_empty());
+    }
+
+    #[test]
+    fn rank_all_filtered_returns_empty() {
+        let results = vec![
+            make_result("https://a.com", "", 10.0),
+            make_result("https://b.com", "too short", 5.0),
+        ];
+        let ranked = rank_and_deduplicate(results, 10);
+        assert!(ranked.is_empty());
+    }
+}

src/models/chat.rs

@@ -105,3 +105,163 @@ pub struct ChatMessage {
     pub attachments: Vec<Attachment>,
     pub timestamp: String,
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use pretty_assertions::assert_eq;
+
+    #[test]
+    fn chat_namespace_default_is_general() {
+        assert_eq!(ChatNamespace::default(), ChatNamespace::General);
+    }
+
+    #[test]
+    fn chat_role_serde_round_trip() {
+        for role in [ChatRole::User, ChatRole::Assistant, ChatRole::System] {
+            let json =
+                serde_json::to_string(&role).unwrap_or_else(|_| panic!("serialize {:?}", role));
+            let back: ChatRole =
+                serde_json::from_str(&json).unwrap_or_else(|_| panic!("deserialize {:?}", role));
+            assert_eq!(role, back);
+        }
+    }
+
+    #[test]
+    fn chat_namespace_serde_round_trip() {
+        for ns in [ChatNamespace::General, ChatNamespace::News] {
+            let json = serde_json::to_string(&ns).unwrap_or_else(|_| panic!("serialize {:?}", ns));
+            let back: ChatNamespace =
+                serde_json::from_str(&json).unwrap_or_else(|_| panic!("deserialize {:?}", ns));
+            assert_eq!(ns, back);
+        }
+    }
+
+    #[test]
+    fn attachment_kind_serde_round_trip() {
+        for kind in [
+            AttachmentKind::Image,
+            AttachmentKind::Document,
+            AttachmentKind::Code,
+        ] {
+            let json =
+                serde_json::to_string(&kind).unwrap_or_else(|_| panic!("serialize {:?}", kind));
+            let back: AttachmentKind =
+                serde_json::from_str(&json).unwrap_or_else(|_| panic!("deserialize {:?}", kind));
+            assert_eq!(kind, back);
+        }
+    }
+
+    #[test]
+    fn attachment_serde_round_trip() {
+        let att = Attachment {
+            name: "photo.png".into(),
+            kind: AttachmentKind::Image,
+            size_bytes: 2048,
+        };
+        let json = serde_json::to_string(&att).expect("serialize Attachment");
+        let back: Attachment = serde_json::from_str(&json).expect("deserialize Attachment");
+        assert_eq!(att, back);
+    }
+
+    #[test]
+    fn chat_session_serde_round_trip() {
+        let session = ChatSession {
+            id: "abc123".into(),
+            user_sub: "user-1".into(),
+            title: "Test Chat".into(),
+            namespace: ChatNamespace::General,
+            provider: "ollama".into(),
+            model: "llama3.1:8b".into(),
+            created_at: "2025-01-01T00:00:00Z".into(),
+            updated_at: "2025-01-01T01:00:00Z".into(),
+            article_url: None,
+        };
+        let json = serde_json::to_string(&session).expect("serialize ChatSession");
+        let back: ChatSession = serde_json::from_str(&json).expect("deserialize ChatSession");
+        assert_eq!(session, back);
+    }
+
+    #[test]
+    fn chat_session_id_alias_deserialization() {
+        // MongoDB returns `_id` instead of `id`
+        let json = r#"{
+            "_id": "mongo-id",
+            "user_sub": "u1",
+            "title": "t",
+            "provider": "ollama",
+            "model": "m",
+            "created_at": "2025-01-01",
+            "updated_at": "2025-01-01"
+        }"#;
+        let session: ChatSession = serde_json::from_str(json).expect("deserialize with _id");
+        assert_eq!(session.id, "mongo-id");
+    }
+
+    #[test]
+    fn chat_session_empty_id_skips_serialization() {
+        let session = ChatSession {
+            id: String::new(),
+            user_sub: "u1".into(),
+            title: "t".into(),
+            namespace: ChatNamespace::default(),
+            provider: "ollama".into(),
+            model: "m".into(),
+            created_at: "2025-01-01".into(),
+            updated_at: "2025-01-01".into(),
+            article_url: None,
+        };
+        let json = serde_json::to_string(&session).expect("serialize");
+        // `id` field should be absent when empty due to skip_serializing_if
+        assert!(!json.contains("\"id\""));
+    }
+
+    #[test]
+    fn chat_session_none_article_url_skips_serialization() {
+        let session = ChatSession {
+            id: "s1".into(),
+            user_sub: "u1".into(),
+            title: "t".into(),
+            namespace: ChatNamespace::default(),
+            provider: "ollama".into(),
+            model: "m".into(),
+            created_at: "2025-01-01".into(),
+            updated_at: "2025-01-01".into(),
+            article_url: None,
+        };
+        let json = serde_json::to_string(&session).expect("serialize");
+        assert!(!json.contains("article_url"));
+    }
+
+    #[test]
+    fn chat_message_serde_round_trip() {
+        let msg = ChatMessage {
+            id: "msg-1".into(),
+            session_id: "s1".into(),
+            role: ChatRole::User,
+            content: "Hello AI".into(),
+            attachments: vec![Attachment {
+                name: "doc.pdf".into(),
+                kind: AttachmentKind::Document,
+                size_bytes: 4096,
+            }],
+            timestamp: "2025-01-01T00:00:00Z".into(),
+        };
+        let json = serde_json::to_string(&msg).expect("serialize ChatMessage");
+        let back: ChatMessage = serde_json::from_str(&json).expect("deserialize ChatMessage");
+        assert_eq!(msg, back);
+    }
+
+    #[test]
+    fn chat_message_id_alias_deserialization() {
+        let json = r#"{
+            "_id": "mongo-msg-id",
+            "session_id": "s1",
+            "role": "User",
+            "content": "hi",
+            "timestamp": "2025-01-01"
+        }"#;
+        let msg: ChatMessage = serde_json::from_str(json).expect("deserialize with _id");
+        assert_eq!(msg.id, "mongo-msg-id");
+    }
+}

src/models/developer.rs

@@ -45,3 +45,63 @@ pub struct AnalyticsMetric {
     pub value: String,
     pub change_pct: f64,
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use pretty_assertions::assert_eq;
+
+    #[test]
+    fn agent_entry_serde_round_trip() {
+        let agent = AgentEntry {
+            id: "a1".into(),
+            name: "RAG Agent".into(),
+            description: "Retrieval-augmented generation".into(),
+            status: "running".into(),
+        };
+        let json = serde_json::to_string(&agent).expect("serialize AgentEntry");
+        let back: AgentEntry = serde_json::from_str(&json).expect("deserialize AgentEntry");
+        assert_eq!(agent, back);
+    }
+
+    #[test]
+    fn flow_entry_serde_round_trip() {
+        let flow = FlowEntry {
+            id: "f1".into(),
+            name: "Data Pipeline".into(),
+            node_count: 5,
+            last_run: Some("2025-06-01T12:00:00Z".into()),
+        };
+        let json = serde_json::to_string(&flow).expect("serialize FlowEntry");
+        let back: FlowEntry = serde_json::from_str(&json).expect("deserialize FlowEntry");
+        assert_eq!(flow, back);
+    }
+
+    #[test]
+    fn flow_entry_with_none_last_run() {
+        let flow = FlowEntry {
+            id: "f2".into(),
+            name: "New Flow".into(),
+            node_count: 0,
+            last_run: None,
+        };
+        let json = serde_json::to_string(&flow).expect("serialize");
+        let back: FlowEntry = serde_json::from_str(&json).expect("deserialize");
+        assert_eq!(flow, back);
+        assert_eq!(back.last_run, None);
+    }
+
+    #[test]
+    fn analytics_metric_negative_change_pct() {
+        let metric = AnalyticsMetric {
+            label: "Latency".into(),
+            value: "120ms".into(),
+            change_pct: -15.5,
+        };
+        let json = serde_json::to_string(&metric).expect("serialize AnalyticsMetric");
+        let back: AnalyticsMetric =
+            serde_json::from_str(&json).expect("deserialize AnalyticsMetric");
+        assert_eq!(metric, back);
+        assert!(back.change_pct < 0.0);
+    }
+}

src/models/news.rs

@@ -23,3 +23,61 @@ pub struct NewsCard {
     pub thumbnail_url: Option<String>,
     pub published_at: String,
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use pretty_assertions::assert_eq;
+
+    #[test]
+    fn news_card_serde_round_trip() {
+        let card = NewsCard {
+            title: "AI Breakthrough".into(),
+            source: "techcrunch.com".into(),
+            summary: "New model released".into(),
+            content: "Full article content here".into(),
+            category: "AI".into(),
+            url: "https://example.com/article".into(),
+            thumbnail_url: Some("https://example.com/thumb.jpg".into()),
+            published_at: "2025-06-01".into(),
+        };
+        let json = serde_json::to_string(&card).expect("serialize NewsCard");
+        let back: NewsCard = serde_json::from_str(&json).expect("deserialize NewsCard");
+        assert_eq!(card, back);
+    }
+
+    #[test]
+    fn news_card_thumbnail_none() {
+        let card = NewsCard {
+            title: "No Thumb".into(),
+            source: "bbc.com".into(),
+            summary: "Summary".into(),
+            content: "Content".into(),
+            category: "Tech".into(),
+            url: "https://bbc.com/article".into(),
+            thumbnail_url: None,
+            published_at: "2025-06-01".into(),
+        };
+        let json = serde_json::to_string(&card).expect("serialize");
+        let back: NewsCard = serde_json::from_str(&json).expect("deserialize");
+        assert_eq!(card, back);
+    }
+
+    #[test]
+    fn news_card_thumbnail_some() {
+        let card = NewsCard {
+            title: "With Thumb".into(),
+            source: "cnn.com".into(),
+            summary: "Summary".into(),
+            content: "Content".into(),
+            category: "News".into(),
+            url: "https://cnn.com/article".into(),
+            thumbnail_url: Some("https://cnn.com/img.jpg".into()),
+            published_at: "2025-06-01".into(),
+        };
+        let json = serde_json::to_string(&card).expect("serialize");
+        assert!(json.contains("img.jpg"));
+        let back: NewsCard = serde_json::from_str(&json).expect("deserialize");
+        assert_eq!(card.thumbnail_url, back.thumbnail_url);
+    }
+}

src/models/organization.rs

@@ -116,3 +116,122 @@ pub struct OrgBillingRecord {
     /// Number of tokens consumed during this cycle.
     pub tokens_used: u64,
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use pretty_assertions::assert_eq;
+
+    #[test]
+    fn member_role_label_admin() {
+        assert_eq!(MemberRole::Admin.label(), "Admin");
+    }
+
+    #[test]
+    fn member_role_label_member() {
+        assert_eq!(MemberRole::Member.label(), "Member");
+    }
+
+    #[test]
+    fn member_role_label_viewer() {
+        assert_eq!(MemberRole::Viewer.label(), "Viewer");
+    }
+
+    #[test]
+    fn member_role_all_returns_three_in_order() {
+        let all = MemberRole::all();
+        assert_eq!(all.len(), 3);
+        assert_eq!(all[0], MemberRole::Admin);
+        assert_eq!(all[1], MemberRole::Member);
+        assert_eq!(all[2], MemberRole::Viewer);
+    }
+
+    #[test]
+    fn member_role_serde_round_trip() {
+        for role in MemberRole::all() {
+            let json =
+                serde_json::to_string(role).unwrap_or_else(|_| panic!("serialize {:?}", role));
+            let back: MemberRole =
+                serde_json::from_str(&json).unwrap_or_else(|_| panic!("deserialize {:?}", role));
+            assert_eq!(*role, back);
+        }
+    }
+
+    #[test]
+    fn org_member_serde_round_trip() {
+        let member = OrgMember {
+            id: "m1".into(),
+            name: "Alice".into(),
+            email: "alice@example.com".into(),
+            role: MemberRole::Admin,
+            joined_at: "2025-01-01T00:00:00Z".into(),
+        };
+        let json = serde_json::to_string(&member).expect("serialize OrgMember");
+        let back: OrgMember = serde_json::from_str(&json).expect("deserialize OrgMember");
+        assert_eq!(member, back);
+    }
+
+    #[test]
+    fn pricing_plan_with_max_seats() {
+        let plan = PricingPlan {
+            id: "team".into(),
+            name: "Team".into(),
+            price_eur: 49,
+            features: vec!["SSO".into(), "Priority".into()],
+            highlighted: true,
+            max_seats: Some(25),
+        };
+        let json = serde_json::to_string(&plan).expect("serialize PricingPlan");
+        let back: PricingPlan = serde_json::from_str(&json).expect("deserialize PricingPlan");
+        assert_eq!(plan, back);
+    }
+
+    #[test]
+    fn pricing_plan_without_max_seats() {
+        let plan = PricingPlan {
+            id: "enterprise".into(),
+            name: "Enterprise".into(),
+            price_eur: 199,
+            features: vec!["Unlimited".into()],
+            highlighted: false,
+            max_seats: None,
+        };
+        let json = serde_json::to_string(&plan).expect("serialize PricingPlan");
+        let back: PricingPlan = serde_json::from_str(&json).expect("deserialize PricingPlan");
+        assert_eq!(plan, back);
+        assert!(json.contains("null") || !json.contains("max_seats"));
+    }
+
+    #[test]
+    fn billing_usage_serde_round_trip() {
+        let usage = BillingUsage {
+            seats_used: 5,
+            seats_total: 10,
+            tokens_used: 1_000_000,
+            tokens_limit: 5_000_000,
+            billing_cycle_end: "2025-12-31".into(),
+        };
+        let json = serde_json::to_string(&usage).expect("serialize BillingUsage");
+        let back: BillingUsage = serde_json::from_str(&json).expect("deserialize BillingUsage");
+        assert_eq!(usage, back);
+    }
+
+    #[test]
+    fn org_settings_default() {
+        let settings = OrgSettings::default();
+        assert_eq!(settings.org_id, "");
+        assert_eq!(settings.plan_id, "");
+        assert!(settings.enabled_features.is_empty());
+        assert_eq!(settings.stripe_customer_id, "");
+    }
+
+    #[test]
+    fn org_billing_record_default() {
+        let record = OrgBillingRecord::default();
+        assert_eq!(record.org_id, "");
+        assert_eq!(record.cycle_start, "");
+        assert_eq!(record.cycle_end, "");
+        assert_eq!(record.seats_used, 0);
+        assert_eq!(record.tokens_used, 0);
+    }
+}

src/models/provider.rs

@@ -72,3 +72,84 @@ pub struct ProviderConfig {
     pub selected_embedding: String,
     pub api_key_set: bool,
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use pretty_assertions::assert_eq;
+
+    #[test]
+    fn llm_provider_label_ollama() {
+        assert_eq!(LlmProvider::Ollama.label(), "Ollama");
+    }
+
+    #[test]
+    fn llm_provider_label_hugging_face() {
+        assert_eq!(LlmProvider::HuggingFace.label(), "Hugging Face");
+    }
+
+    #[test]
+    fn llm_provider_label_openai() {
+        assert_eq!(LlmProvider::OpenAi.label(), "OpenAI");
+    }
+
+    #[test]
+    fn llm_provider_label_anthropic() {
+        assert_eq!(LlmProvider::Anthropic.label(), "Anthropic");
+    }
+
+    #[test]
+    fn llm_provider_serde_round_trip() {
+        for variant in [
+            LlmProvider::Ollama,
+            LlmProvider::HuggingFace,
+            LlmProvider::OpenAi,
+            LlmProvider::Anthropic,
+        ] {
+            let json = serde_json::to_string(&variant)
+                .unwrap_or_else(|_| panic!("serialize {:?}", variant));
+            let back: LlmProvider =
+                serde_json::from_str(&json).unwrap_or_else(|_| panic!("deserialize {:?}", variant));
+            assert_eq!(variant, back);
+        }
+    }
+
+    #[test]
+    fn model_entry_serde_round_trip() {
+        let entry = ModelEntry {
+            id: "llama3.1:8b".into(),
+            name: "Llama 3.1 8B".into(),
+            provider: LlmProvider::Ollama,
+            context_window: 8192,
+        };
+        let json = serde_json::to_string(&entry).expect("serialize ModelEntry");
+        let back: ModelEntry = serde_json::from_str(&json).expect("deserialize ModelEntry");
+        assert_eq!(entry, back);
+    }
+
+    #[test]
+    fn embedding_entry_serde_round_trip() {
+        let entry = EmbeddingEntry {
+            id: "nomic-embed".into(),
+            name: "Nomic Embed".into(),
+            provider: LlmProvider::HuggingFace,
+            dimensions: 768,
+        };
+        let json = serde_json::to_string(&entry).expect("serialize EmbeddingEntry");
+        let back: EmbeddingEntry = serde_json::from_str(&json).expect("deserialize EmbeddingEntry");
+        assert_eq!(entry, back);
+    }
+
+    #[test]
+    fn provider_config_serde_round_trip() {
+        let cfg = ProviderConfig {
+            provider: LlmProvider::Anthropic,
+            selected_model: "claude-3".into(),
+            selected_embedding: "embed-v1".into(),
+            api_key_set: true,
+        };
+        let json = serde_json::to_string(&cfg).expect("serialize ProviderConfig");
+        let back: ProviderConfig = serde_json::from_str(&json).expect("deserialize ProviderConfig");
+        assert_eq!(cfg, back);
+    }
+}

src/models/user.rs

@@ -70,3 +70,81 @@ pub struct UserPreferences {
     #[serde(default)]
     pub provider_config: UserProviderConfig,
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use pretty_assertions::assert_eq;
+
+    #[test]
+    fn user_data_default() {
+        let ud = UserData::default();
+        assert_eq!(ud.name, "");
+    }
+
+    #[test]
+    fn auth_info_default_not_authenticated() {
+        let info = AuthInfo::default();
+        assert!(!info.authenticated);
+        assert_eq!(info.sub, "");
+        assert_eq!(info.email, "");
+        assert_eq!(info.name, "");
+        assert_eq!(info.avatar_url, "");
+        assert_eq!(info.librechat_url, "");
+    }
+
+    #[test]
+    fn auth_info_serde_round_trip() {
+        let info = AuthInfo {
+            authenticated: true,
+            sub: "sub-123".into(),
+            email: "test@example.com".into(),
+            name: "Test User".into(),
+            avatar_url: "https://example.com/avatar.png".into(),
+            librechat_url: "https://chat.example.com".into(),
+        };
+        let json = serde_json::to_string(&info).expect("serialize AuthInfo");
+        let back: AuthInfo = serde_json::from_str(&json).expect("deserialize AuthInfo");
+        assert_eq!(info, back);
+    }
+
+    #[test]
+    fn user_preferences_default() {
+        let prefs = UserPreferences::default();
+        assert_eq!(prefs.sub, "");
+        assert_eq!(prefs.org_id, "");
+        assert!(prefs.custom_topics.is_empty());
+        assert!(prefs.recent_searches.is_empty());
+    }
+
+    #[test]
+    fn user_provider_config_optional_keys_skip_none() {
+        let cfg = UserProviderConfig {
+            default_provider: "ollama".into(),
+            default_model: "llama3.1:8b".into(),
+            openai_api_key: None,
+            anthropic_api_key: None,
+            huggingface_api_key: None,
+            ollama_url_override: String::new(),
+        };
+        let json = serde_json::to_string(&cfg).expect("serialize UserProviderConfig");
+        assert!(!json.contains("openai_api_key"));
+        assert!(!json.contains("anthropic_api_key"));
+        assert!(!json.contains("huggingface_api_key"));
+    }
+
+    #[test]
+    fn user_provider_config_serde_round_trip_with_keys() {
+        let cfg = UserProviderConfig {
+            default_provider: "openai".into(),
+            default_model: "gpt-4o".into(),
+            openai_api_key: Some("sk-test".into()),
+            anthropic_api_key: Some("ak-test".into()),
+            huggingface_api_key: None,
+            ollama_url_override: "http://custom:11434".into(),
+        };
+        let json = serde_json::to_string(&cfg).expect("serialize");
+        let back: UserProviderConfig = serde_json::from_str(&json).expect("deserialize");
+        assert_eq!(cfg, back);
+    }
+}