Wrap the per-resource extras, activities, email history and previews

Forty-one hand-written endpoints, taking the crate from 284 methods to 325:
the per-resource extras (webhook retry, task sorting, default design,
subscription steps, the company gateway and bank integration actions, and
the client extras), the password-protected destructive actions (client and
company purges, client and vendor merges, user invite and purge), the
activity list, feed, per-entity feed and note, email history, and the six
preview routes.

The password-protected actions send `X-API-PASSWORD`, falling back to
`X-API-PASSWORD-BASE64` when the password holds a control character, which
cannot go in a header value. None of the destructive actions are replayed
on a 5xx, and neither are the notes.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/client.rs

@@ -6,12 +6,13 @@ use serde::{de::DeserializeOwned, Serialize};
 
 use crate::error::{ApiErrorBody, Error, Result};
 use crate::models::{
-    BankIntegration, BankTransaction, BankTransactionRule, BulkRequest, Client as ClientModel,
-    ClientGatewayToken, Company, CompanyGateway, CompanyToken, Credit, Design, Document, Expense,
-    ExpenseCategory, GroupSetting, HealthCheck, Invoice, ItemResponse, ListParams, ListResponse,
-    Location, Payment, PaymentTerm, Product, Project, PurchaseOrder, Quote, RecurringExpense,
-    RecurringInvoice, RecurringQuote, SearchResults, Statics, Subscription, SystemLog, Tag, Task,
-    TaskScheduler, TaskStatus, TaxRate, User, Vendor, Webhook,
+    Activity, ActivityFeedEntry, BankIntegration, BankTransaction, BankTransactionRule,
+    BulkRequest, Client as ClientModel, ClientGatewayToken, Company, CompanyGateway, CompanyToken,
+    Credit, Design, Document, Expense, ExpenseCategory, GroupSetting, HealthCheck, Invoice,
+    ItemResponse, ListParams, ListResponse, Location, MessageResponse, Payment, PaymentTerm,
+    Product, Project, PurchaseOrder, Quote, RecurringExpense, RecurringInvoice, RecurringQuote,
+    SearchResults, Statics, Subscription, SubscriptionStep, SystemLog, Tag, Task, TaskScheduler,
+    TaskStatus, TaxRate, User, Vendor, Webhook,
 };
 use crate::retry::{self, RetryPolicy};
 use crate::upload::FileUpload;
@@ -61,6 +62,28 @@ fn seg(value: &str) -> Result<impl std::fmt::Display + '_> {
     Ok(utf8_percent_encode(value, PATH_SEGMENT))
 }
 
+/// Standard base64 with padding. Only used for the one header that needs it,
+/// which is not worth a dependency.
+fn base64(bytes: &[u8]) -> String {
+    const ALPHABET: &[u8; 64] = b"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
+    let mut out = String::with_capacity(bytes.len().div_ceil(3) * 4);
+    for chunk in bytes.chunks(3) {
+        let n = chunk
+            .iter()
+            .enumerate()
+            .fold(0u32, |n, (i, b)| n | (*b as u32) << (16 - 8 * i));
+        for i in 0..4 {
+            if i <= chunk.len() {
+                out.push(ALPHABET[(n >> (18 - 6 * i) & 63) as usize] as char);
+            } else {
+                out.push('=');
+            }
+        }
+    }
+    out
+}
+
 /// Renders the start of a response body for an error message.
 ///
 /// Collapsed to one line and truncated, so a stray HTML error page or a
@@ -102,9 +125,9 @@ fn excerpt(bytes: &[u8]) -> String {
 pub struct InvoiceNinjaClient {
     http: reqwest::Client,
     base_url: String,
-    /// Marked sensitive, so it renders as `Sensitive` rather than the value
-    /// in the derived `Debug`.
-    api_password: Option<header::HeaderValue>,
+    /// The header to send it under, and its value. Marked sensitive, so it
+    /// renders as `Sensitive` rather than the value in the derived `Debug`.
+    api_password: Option<(&'static str, header::HeaderValue)>,
     timeout: Duration,
     retry: RetryPolicy,
 }
@@ -185,7 +208,14 @@ impl InvoiceNinjaClient {
     /// middleware and reject requests without the account password, even
     /// when the token is valid: reading or writing an individual user,
     /// `/users/bulk`, purging a client or company, and merging clients.
-    /// Without this, those calls fail rather than returning data.
+    /// Without this, those calls fail rather than returning data. (The
+    /// server also lets a recent password-authenticated session through
+    /// without the header, so an omitted password is not always refused.)
+    ///
+    /// A password that fits a header value is sent as `X-API-PASSWORD`. One
+    /// that does not (it contains a control character such as a newline) is
+    /// sent as `X-API-PASSWORD-BASE64`, which the server's middleware decodes.
+    /// It used to be refused locally with a misleading `InvalidToken`.
     ///
     /// ```no_run
     /// # fn main() -> invoiceninjars::Result<()> {
@@ -197,10 +227,17 @@ impl InvoiceNinjaClient {
     /// # }
     /// ```
     pub fn with_api_password(mut self, password: impl Into<String>) -> Result<Self> {
-        let mut value = header::HeaderValue::from_str(&password.into())
-            .map_err(|e| Error::InvalidToken(e.to_string()))?;
+        let password = password.into();
+        let (name, mut value) = match header::HeaderValue::from_str(&password) {
+            Ok(value) => ("X-API-PASSWORD", value),
+            Err(_) => (
+                "X-API-PASSWORD-BASE64",
+                header::HeaderValue::from_str(&base64(password.as_bytes()))
+                    .expect("base64 output is always a valid header value"),
+            ),
+        };
         value.set_sensitive(true);
-        self.api_password = Some(value);
+        self.api_password = Some((name, value));
         Ok(self)
     }
 
@@ -212,7 +249,7 @@ impl InvoiceNinjaClient {
             .request(method, self.url(path))
             .timeout(self.timeout);
         match &self.api_password {
-            Some(password) => builder.header("X-API-PASSWORD", password.clone()),
+            Some((name, password)) => builder.header(*name, password.clone()),
             None => builder,
         }
     }
@@ -596,6 +633,10 @@ impl InvoiceNinjaClient {
     async fn get_discard(&self, path: &str) -> Result<()> {
         self.get_raw(path).await.map(|_| ())
     }
+
+    async fn post_discard<B: Serialize>(&self, path: &str, payload: &B) -> Result<()> {
+        self.post_raw(path, payload).await.map(|_| ())
+    }
 }
 
 /// Generates typed list/list_all/get/create/update/delete methods for a
@@ -1419,3 +1460,450 @@ impl InvoiceNinjaClient {
             .await
     }
 }
+
+/// Per-resource routes that sit beside the CRUD set. Each answers with its
+/// own shape (checked against the upstream controllers), so none of them is
+/// macro-generated.
+///
+/// All are `POST` unless noted, so none is retried on a 5xx or a timeout.
+/// Several are no-body triggers; they send `{}` rather than an empty body.
+impl InvoiceNinjaClient {
+    // --- webhooks, tasks, designs ---------------------------------------
+
+    /// Re-sends a webhook for one entity. `body` takes `entity` (e.g.
+    /// `invoice`) and `entity_id`. Answers with the webhook itself, not the
+    /// delivery result.
+    pub async fn retry_webhook<B: Serialize>(&self, id: &str, body: &B) -> Result<Webhook> {
+        self.post_one(&format!("webhooks/{}/retry", seg(id)?), body)
+            .await
+    }
+
+    /// Reorders task-board columns and the tasks in them. `body` takes
+    /// `status_ids` (task status ids, in order) and `task_ids` (a map from
+    /// task status id to the ordered task ids in that column).
+    pub async fn sort_tasks<B: Serialize>(&self, body: &B) -> Result<MessageResponse> {
+        self.post_unwrapped("tasks/sort", body).await
+    }
+
+    /// Makes a design the default for an entity. `body` takes `design_id`
+    /// and `entity`, and optionally `settings_level` (`company`,
+    /// `group_settings`, or `client`) with the matching `group_settings_id`
+    /// or `client_id`.
+    pub async fn set_default_design<B: Serialize>(&self, body: &B) -> Result<MessageResponse> {
+        self.post_unwrapped("designs/set/default", body).await
+    }
+
+    // --- client gateway tokens ------------------------------------------
+
+    /// Makes a stored payment method the client's default.
+    pub async fn set_default_client_gateway_token(&self, id: &str) -> Result<ClientGatewayToken> {
+        self.post_one(
+            &format!("client_gateway_tokens/{}/setAsDefault", seg(id)?),
+            &serde_json::json!({}),
+        )
+        .await
+    }
+
+    // --- subscriptions --------------------------------------------------
+
+    /// The steps of the purchase flow and what each depends on.
+    ///
+    /// There is no `data` wrapper. The server sends a JSON object keyed by
+    /// the PHP class behind each step (the controller's `collect()` keeps
+    /// those keys), though the upstream source reads as if it were a list.
+    /// Both shapes decode here; the keys are dropped, since each step's `id`
+    /// says the same thing, and the order of the result is not meaningful.
+    pub async fn subscription_steps(&self) -> Result<Vec<SubscriptionStep>> {
+        #[derive(serde::Deserialize)]
+        #[serde(untagged)]
+        enum Steps {
+            List(Vec<SubscriptionStep>),
+            Keyed(std::collections::BTreeMap<String, SubscriptionStep>),
+        }
+
+        Ok(match self.get_unwrapped("subscriptions/steps").await? {
+            Steps::List(steps) => steps,
+            Steps::Keyed(steps) => steps.into_values().collect(),
+        })
+    }
+
+    /// Validates a proposed `steps` list against the dependency rules.
+    /// Succeeds on a valid list; an invalid one is a 422
+    /// ([`Error::Api`]) carrying the reason.
+    pub async fn check_subscription_steps<B: Serialize>(&self, body: &B) -> Result<()> {
+        self.post_discard("subscriptions/steps/check", body).await
+    }
+
+    // --- company gateways -----------------------------------------------
+
+    /// Asks the gateway to verify its credentials. The outcome is in the
+    /// returned message; a failed check is still an HTTP 200.
+    pub async fn test_company_gateway(&self, id: &str) -> Result<MessageResponse> {
+        self.post_unwrapped(
+            &format!("company_gateways/{}/test", seg(id)?),
+            &serde_json::json!({}),
+        )
+        .await
+    }
+
+    /// Duplicates a company gateway, returning the copy.
+    pub async fn clone_company_gateway(&self, id: &str) -> Result<CompanyGateway> {
+        self.post_one(
+            &format!("company_gateways/{}/clone", seg(id)?),
+            &serde_json::json!({}),
+        )
+        .await
+    }
+
+    /// Starts importing the gateway's customers as clients. The import runs
+    /// in the background; the message only confirms it was queued.
+    pub async fn import_company_gateway_customers(&self, id: &str) -> Result<MessageResponse> {
+        self.post_unwrapped(
+            &format!("company_gateways/{}/import_customers", seg(id)?),
+            &serde_json::json!({}),
+        )
+        .await
+    }
+
+    // --- bank integrations and transactions -----------------------------
+
+    /// Asks the server to refresh every linked bank account. The response
+    /// body is a serialised query builder with no usable content, so it is
+    /// discarded; list the integrations afterwards to see the result.
+    /// Throttled to 30 calls a minute.
+    pub async fn refresh_bank_accounts(&self) -> Result<()> {
+        self.post_discard("bank_integrations/refresh_accounts", &serde_json::json!({}))
+            .await
+    }
+
+    /// Disconnects a bank account, returning the updated integration.
+    /// `account_id` is the provider's account id, not the integration's.
+    pub async fn remove_bank_account(&self, account_id: &str) -> Result<BankIntegration> {
+        self.post_one(
+            &format!("bank_integrations/remove_account/{}", seg(account_id)?),
+            &serde_json::json!({}),
+        )
+        .await
+    }
+
+    /// Starts fetching transactions for every auto-sync integration. Despite
+    /// the `account_id` in the route, the server ignores it. Throttled to one
+    /// call a minute.
+    pub async fn fetch_bank_transactions(&self, account_id: &str) -> Result<MessageResponse> {
+        self.post_unwrapped(
+            &format!("bank_integrations/get_transactions/{}", seg(account_id)?),
+            &serde_json::json!({}),
+        )
+        .await
+    }
+
+    /// Matches bank transactions to invoices, payments, or expenses. `body`
+    /// takes a `transactions` array; the matched transactions come back.
+    pub async fn match_bank_transactions<B: Serialize>(
+        &self,
+        body: &B,
+    ) -> Result<Vec<BankTransaction>> {
+        self.post_list("bank_transactions/match", body).await
+    }
+
+    // --- client extras --------------------------------------------------
+
+    /// Re-fetches the client's tax data from the tax provider. Throttled to
+    /// 10 calls a minute.
+    pub async fn update_client_tax_data(&self, id: &str) -> Result<ClientModel> {
+        self.post_one(
+            &format!("clients/{}/updateTaxData", seg(id)?),
+            &serde_json::json!({}),
+        )
+        .await
+    }
+
+    /// The client's effective settings, each tagged with the level it came
+    /// from. Left as raw JSON: the map's keys are the settings themselves.
+    pub async fn client_show_settings(&self, id: &str) -> Result<serde_json::Value> {
+        self.post_unwrapped(
+            &format!("clients/{}/show_settings", seg(id)?),
+            &serde_json::json!({}),
+        )
+        .await
+    }
+
+    /// Looks the client up on the Peppol network. Left as raw JSON: the
+    /// controller returns whatever the discovery service produced.
+    pub async fn client_peppol_discovery(&self, id: &str) -> Result<serde_json::Value> {
+        self.post_unwrapped(
+            &format!("clients/{}/peppol_discovery", seg(id)?),
+            &serde_json::json!({}),
+        )
+        .await
+    }
+
+    /// Validates the client's VAT number. Updates the client's VAT status as
+    /// a side effect.
+    pub async fn check_client_vat(&self, id: &str) -> Result<MessageResponse> {
+        self.post_unwrapped(
+            &format!("clients/{}/check_vat", seg(id)?),
+            &serde_json::json!({}),
+        )
+        .await
+    }
+
+    /// The client's VAT validation status. A `GET`, and the only read-only
+    /// method in this block.
+    pub async fn client_vat_status(&self, id: &str) -> Result<MessageResponse> {
+        self.get_unwrapped(&format!("clients/{}/vat_status", seg(id)?))
+            .await
+    }
+
+    /// Every document attached to the client or to its invoices, quotes,
+    /// credits, expenses, payments, tasks, recurring invoices, recurring
+    /// expenses, and projects. `body` takes `filter` (a name substring) and
+    /// `sort` (`column|asc` or `column|desc`). Returns one page.
+    pub async fn client_documents<B: Serialize>(
+        &self,
+        id: &str,
+        body: &B,
+    ) -> Result<Vec<Document>> {
+        self.post_list(&format!("clients/{}/documents", seg(id)?), body)
+            .await
+    }
+}
+
+/// Destructive actions behind the API's `password_protected` middleware.
+///
+/// Every method here needs
+/// [`with_api_password`](InvoiceNinjaClient::with_api_password); without it
+/// the server normally refuses the request. Most are **irreversible**: a purge
+/// force-deletes rows rather than archiving them, and a merge removes one of
+/// the two records.
+///
+/// All are `POST`s, so none is retried on a 5xx or a timeout. That matters
+/// most here: replaying a merge after a lost response could act on a record
+/// that no longer exists.
+impl InvoiceNinjaClient {
+    /// Permanently deletes a client and its documents. Unlike
+    /// [`delete_client`](Self::delete_client), which soft-deletes, this cannot
+    /// be undone.
+    pub async fn purge_client(&self, id: &str) -> Result<MessageResponse> {
+        self.post_unwrapped(
+            &format!("clients/{}/purge", seg(id)?),
+            &serde_json::json!({}),
+        )
+        .await
+    }
+
+    /// Merges `mergeable_id` into `id`, returning the client that is kept.
+    ///
+    /// The route is `clients/{id}/{mergeable_id}/merge` and the controller
+    /// calls `merge` on the first, so `id` is the survivor. Merging a client
+    /// into itself, or naming one that does not exist, is a 400.
+    pub async fn merge_clients(&self, id: &str, mergeable_id: &str) -> Result<ClientModel> {
+        self.post_one(
+            &format!("clients/{}/{}/merge", seg(id)?, seg(mergeable_id)?),
+            &serde_json::json!({}),
+        )
+        .await
+    }
+
+    /// Merges `mergeable_id` into `id`, returning the vendor that is kept.
+    /// Same semantics as [`merge_clients`](Self::merge_clients).
+    pub async fn merge_vendors(&self, id: &str, mergeable_id: &str) -> Result<Vendor> {
+        self.post_one(
+            &format!("vendors/{}/{}/merge", seg(id)?, seg(mergeable_id)?),
+            &serde_json::json!({}),
+        )
+        .await
+    }
+
+    /// Deletes a company. The hosted app refuses to purge its default
+    /// company with a 400.
+    pub async fn purge_company(&self, id: &str) -> Result<MessageResponse> {
+        self.post_unwrapped(
+            &format!("companies/purge/{}", seg(id)?),
+            &serde_json::json!({}),
+        )
+        .await
+    }
+
+    /// Force-deletes a company's clients, products, projects, tasks, vendors,
+    /// expenses, purchase orders, bank transactions and activity, and resets
+    /// its number counters. The company, its settings, and its invoices
+    /// remain as the server leaves them.
+    pub async fn purge_company_save_settings(&self, id: &str) -> Result<MessageResponse> {
+        self.post_unwrapped(
+            &format!("companies/purge_save_settings/{}", seg(id)?),
+            &serde_json::json!({}),
+        )
+        .await
+    }
+
+    /// Re-sends a user's invitation email.
+    pub async fn invite_user(&self, id: &str) -> Result<MessageResponse> {
+        self.post_unwrapped(
+            &format!("users/{}/invite", seg(id)?),
+            &serde_json::json!({}),
+        )
+        .await
+    }
+
+    /// Permanently deletes a user. Only the account owner may, and not
+    /// themselves. The server answers 204 with no body.
+    pub async fn purge_user(&self, id: &str) -> Result<()> {
+        self.post_discard(&format!("users/{}/purge", seg(id)?), &serde_json::json!({}))
+            .await
+    }
+
+    /// A blank user as the server would create it, for filling in and
+    /// passing to [`create_user`](Self::create_user). Nothing is stored.
+    pub async fn new_user_template(&self) -> Result<User> {
+        self.get_one("users/create").await
+    }
+}
+
+/// Activity log, email history, and document previews. Each has a response
+/// shape of its own (read from the upstream controllers, and for the activity
+/// routes confirmed against a 5.13.50 server), so none is macro-generated.
+impl InvoiceNinjaClient {
+    // --- activities -----------------------------------------------------
+
+    /// One page of the activity log, newest first.
+    ///
+    /// The server takes its row limit from a `rows` parameter (default 75)
+    /// rather than `per_page`, though it paginates the result as well; use
+    /// [`ListParams::param`] to pass `rows`.
+    pub async fn list_activities(&self, params: &ListParams) -> Result<Vec<Activity>> {
+        self.get_list("activities", params).await
+    }
+
+    pub async fn list_all_activities(&self, params: &ListParams) -> Result<Vec<Activity>> {
+        self.get_all_pages("activities", params).await
+    }
+
+    /// The activity log as the web app shows it: each entry's records are
+    /// resolved into labelled references, newest first. Non-admins see only
+    /// their own activity. `rows` defaults to 75 on the server.
+    pub async fn activity_feed(&self, rows: Option<u32>) -> Result<Vec<ActivityFeedEntry>> {
+        let mut params = ListParams::new().param("reactv2", "1");
+        if let Some(rows) = rows {
+            params = params.param("rows", rows.to_string());
+        }
+        self.get_list("activities", &params).await
+    }
+
+    /// The feed for one record. `entity` is the **singular** name (`invoice`,
+    /// `quote`, `credit`, `purchase_order`, `payment`, `client`, `vendor`,
+    /// `expense`, `task`, `project`, `subscription`, `recurring_invoice`).
+    /// Contrast [`add_activity_note`](Self::add_activity_note), which wants
+    /// the plural.
+    pub async fn entity_activity(
+        &self,
+        entity: &str,
+        entity_id: &str,
+        rows: Option<u32>,
+    ) -> Result<Vec<ActivityFeedEntry>> {
+        let mut body = serde_json::json!({ "entity": entity, "entity_id": entity_id });
+        // Left out rather than sent as null: the server tests for the key's
+        // presence, so a null `rows` would count as given and remove the cap.
+        if let Some(rows) = rows {
+            body["rows"] = rows.into();
+        }
+        self.post_list("activities/entity", &body).await
+    }
+
+    /// Adds a note to a record's history. `entity` is the **plural** table
+    /// name (`invoices`, `quotes`, `credits`, `recurring_invoices`,
+    /// `clients`, `vendors`, `payments`, `projects`, `tasks`, `expenses`,
+    /// `recurring_expenses`, `bank_transactions`, `purchase_orders`), unlike
+    /// [`entity_activity`](Self::entity_activity).
+    ///
+    /// Not idempotent: each call adds another note, so it is not retried on a
+    /// 5xx.
+    pub async fn add_activity_note(
+        &self,
+        entity: &str,
+        entity_id: &str,
+        notes: &str,
+    ) -> Result<Activity> {
+        self.post_one(
+            "activities/notes",
+            &serde_json::json!({ "entity": entity, "entity_id": entity_id, "notes": notes }),
+        )
+        .await
+    }
+
+    /// The PDF of an invoice, quote or credit as it was when the activity was
+    /// recorded. A 404 means that activity kept no backup.
+    pub async fn download_activity_entity(&self, activity_id: &str) -> Result<Vec<u8>> {
+        self.get_raw(&format!("activities/download_entity/{}", seg(activity_id)?))
+            .await
+    }
+
+    // --- email history --------------------------------------------------
+
+    /// The client's email delivery history, newest first: one object per sent
+    /// message that has delivery events. Left as raw JSON, since the objects
+    /// mirror whatever the mail provider reported and no instance available
+    /// here had sent mail to take a shape from.
+    pub async fn client_email_history(&self, client_id: &str) -> Result<Vec<serde_json::Value>> {
+        self.post_unwrapped(
+            &format!("emails/clientHistory/{}", seg(client_id)?),
+            &serde_json::json!({}),
+        )
+        .await
+    }
+
+    /// Email delivery history for one record. `entity` is `invoice`, `quote`,
+    /// `credit`, `recurring_invoice`, or `purchase_order`. Raw JSON, as for
+    /// [`client_email_history`](Self::client_email_history).
+    pub async fn entity_email_history(
+        &self,
+        entity: &str,
+        entity_id: &str,
+    ) -> Result<Vec<serde_json::Value>> {
+        self.post_unwrapped(
+            "emails/entityHistory",
+            &serde_json::json!({ "entity": entity, "entity_id": entity_id }),
+        )
+        .await
+    }
+
+    // --- previews -------------------------------------------------------
+    //
+    // These render a document without saving it and answer with a PDF, so
+    // they return the bytes. `body` is the entity to render plus, for the
+    // design routes, the `design` object.
+
+    /// Renders a preview of an existing record or of an unsaved design.
+    /// Takes `entity`, `entity_id` (`-1` for a mock record) and `design`.
+    pub async fn preview<B: Serialize>(&self, body: &B) -> Result<Vec<u8>> {
+        self.post_raw("preview", body).await
+    }
+
+    /// [`preview`](Self::preview) as the HTML the PDF is made from.
+    pub async fn preview_html<B: Serialize>(&self, body: &B) -> Result<String> {
+        let bytes = self.post_raw("preview?html=true", body).await?;
+        Ok(String::from_utf8_lossy(&bytes).into_owned())
+    }
+
+    /// Renders an unsaved invoice, quote, credit or recurring invoice as a
+    /// PDF: the body is the entity's own fields, plus `entity` and
+    /// `entity_id`.
+    pub async fn live_preview<B: Serialize>(&self, body: &B) -> Result<Vec<u8>> {
+        self.post_raw("live_preview", body).await
+    }
+
+    /// Renders a design against mock data, for editing it.
+    pub async fn live_design<B: Serialize>(&self, body: &B) -> Result<Vec<u8>> {
+        self.post_raw("live_design", body).await
+    }
+
+    /// [`preview`](Self::preview) for a purchase order.
+    pub async fn preview_purchase_order<B: Serialize>(&self, body: &B) -> Result<Vec<u8>> {
+        self.post_raw("preview/purchase_order", body).await
+    }
+
+    /// [`live_preview`](Self::live_preview) for a purchase order.
+    pub async fn live_preview_purchase_order<B: Serialize>(&self, body: &B) -> Result<Vec<u8>> {
+        self.post_raw("live_preview/purchase_order", body).await
+    }
+}

tests/client_requests.rs

@@ -1475,3 +1475,749 @@ async fn transport_errors_say_why_the_request_failed() {
         "the cause should appear in the message, got: {rendered}"
     );
 }
+
+// --- per-resource extras ------------------------------------------------
+
+/// Mounts one route answering 200 with `body`, and returns the server.
+async fn route_server(verb: &str, route: &str, body: serde_json::Value) -> MockServer {
+    let server = MockServer::start().await;
+    Mock::given(method(verb))
+        .and(path(route))
+        .respond_with(ResponseTemplate::new(200).set_body_json(body))
+        .expect(1)
+        .mount(&server)
+        .await;
+    server
+}
+
+/// Generates one test per extra. Each mounts the route the upstream router
+/// registers, calls the method, and checks it decoded the shape the
+/// controller returns. `route_server` expects exactly one request, so a call
+/// that hit a different path or verb fails when the server drops.
+macro_rules! extra_test {
+    ($name:ident, $verb:literal, $route:literal, $response:expr,
+     |$c:ident| $call:expr, |$got:ident| $check:expr) => {
+        #[tokio::test]
+        async fn $name() {
+            let server = route_server($verb, $route, $response).await;
+            let $c = client(&server);
+            let $got = $call.await.expect("the extra should succeed");
+            $check;
+        }
+    };
+}
+
+fn message() -> serde_json::Value {
+    json!({ "message": "ok" })
+}
+
+fn entity() -> serde_json::Value {
+    json!({ "data": { "id": "abc" } })
+}
+
+extra_test!(
+    retry_webhook_posts_to_retry_and_returns_the_webhook,
+    "POST",
+    "/webhooks/abc/retry",
+    entity(),
+    |c| c.retry_webhook("abc", &json!({ "entity": "invoice", "entity_id": "i1" })),
+    |hook| assert_eq!(hook.id.as_deref(), Some("abc"))
+);
+
+extra_test!(
+    sort_tasks_returns_the_message,
+    "POST",
+    "/tasks/sort",
+    message(),
+    |c| c.sort_tasks(&json!({ "status_ids": ["s1"], "task_ids": { "s1": ["t1"] } })),
+    |got| assert_eq!(got.message, "ok")
+);
+
+extra_test!(
+    set_default_design_returns_the_message,
+    "POST",
+    "/designs/set/default",
+    message(),
+    |c| c.set_default_design(&json!({ "design_id": "d1", "entity": "invoice" })),
+    |got| assert_eq!(got.message, "ok")
+);
+
+extra_test!(
+    set_default_client_gateway_token_returns_the_token,
+    "POST",
+    "/client_gateway_tokens/abc/setAsDefault",
+    json!({ "data": { "id": "abc", "is_default": true } }),
+    |c| c.set_default_client_gateway_token("abc"),
+    |token| assert!(token.is_default)
+);
+
+extra_test!(
+    test_company_gateway_returns_the_message,
+    "POST",
+    "/company_gateways/abc/test",
+    message(),
+    |c| c.test_company_gateway("abc"),
+    |got| assert_eq!(got.message, "ok")
+);
+
+extra_test!(
+    clone_company_gateway_returns_the_copy,
+    "POST",
+    "/company_gateways/abc/clone",
+    entity(),
+    |c| c.clone_company_gateway("abc"),
+    |copy| assert_eq!(copy.id.as_deref(), Some("abc"))
+);
+
+extra_test!(
+    import_company_gateway_customers_returns_the_message,
+    "POST",
+    "/company_gateways/abc/import_customers",
+    message(),
+    |c| c.import_company_gateway_customers("abc"),
+    |got| assert_eq!(got.message, "ok")
+);
+
+extra_test!(
+    remove_bank_account_returns_the_integration,
+    "POST",
+    "/bank_integrations/remove_account/acc1",
+    entity(),
+    |c| c.remove_bank_account("acc1"),
+    |got| assert_eq!(got.id.as_deref(), Some("abc"))
+);
+
+extra_test!(
+    fetch_bank_transactions_returns_the_message,
+    "POST",
+    "/bank_integrations/get_transactions/acc1",
+    message(),
+    |c| c.fetch_bank_transactions("acc1"),
+    |got| assert_eq!(got.message, "ok")
+);
+
+extra_test!(
+    match_bank_transactions_returns_the_matched_rows,
+    "POST",
+    "/bank_transactions/match",
+    json!({ "data": [{ "id": "bt1" }] }),
+    |c| c.match_bank_transactions(&json!({ "transactions": [] })),
+    |got| assert_eq!(got.len(), 1)
+);
+
+extra_test!(
+    update_client_tax_data_returns_the_client,
+    "POST",
+    "/clients/abc/updateTaxData",
+    entity(),
+    |c| c.update_client_tax_data("abc"),
+    |got| assert_eq!(got.id.as_deref(), Some("abc"))
+);
+
+extra_test!(
+    client_show_settings_returns_raw_json,
+    "POST",
+    "/clients/abc/show_settings",
+    json!({ "currency_id": "1" }),
+    |c| c.client_show_settings("abc"),
+    |got| assert_eq!(got["currency_id"], "1")
+);
+
+extra_test!(
+    client_peppol_discovery_returns_raw_json,
+    "POST",
+    "/clients/abc/peppol_discovery",
+    json!({ "found": false }),
+    |c| c.client_peppol_discovery("abc"),
+    |got| assert_eq!(got["found"], false)
+);
+
+extra_test!(
+    check_client_vat_returns_the_message,
+    "POST",
+    "/clients/abc/check_vat",
+    message(),
+    |c| c.check_client_vat("abc"),
+    |got| assert_eq!(got.message, "ok")
+);
+
+extra_test!(
+    client_vat_status_is_a_get,
+    "GET",
+    "/clients/abc/vat_status",
+    message(),
+    |c| c.client_vat_status("abc"),
+    |got| assert_eq!(got.message, "ok")
+);
+
+extra_test!(
+    client_documents_returns_one_page_of_documents,
+    "POST",
+    "/clients/abc/documents",
+    json!({ "data": [{ "id": "d1" }] }),
+    |c| c.client_documents("abc", &json!({ "filter": "x" })),
+    |got| assert_eq!(got.len(), 1)
+);
+
+/// The body a caller passes must reach the server, not just the route.
+#[tokio::test]
+async fn retry_webhook_sends_the_callers_body() {
+    let server = route_server("POST", "/webhooks/abc/retry", entity()).await;
+    client(&server)
+        .retry_webhook("abc", &json!({ "entity": "invoice", "entity_id": "i1" }))
+        .await
+        .unwrap();
+
+    let sent: serde_json::Value = server.received_requests().await.unwrap()[0]
+        .body_json()
+        .unwrap();
+    assert_eq!(sent, json!({ "entity": "invoice", "entity_id": "i1" }));
+}
+
+/// The no-body triggers send `{}` with a JSON content type rather than an
+/// empty body, which is what Laravel's request parsing is happy with.
+#[tokio::test]
+async fn no_body_triggers_send_an_empty_json_object() {
+    let server = route_server("POST", "/company_gateways/abc/test", message()).await;
+    client(&server).test_company_gateway("abc").await.unwrap();
+
+    let request = &server.received_requests().await.unwrap()[0];
+    assert_eq!(request.body_json::<serde_json::Value>().unwrap(), json!({}));
+    assert_eq!(
+        request.headers.get("content-type").unwrap(),
+        "application/json"
+    );
+}
+
+#[tokio::test]
+async fn subscription_steps_decode_a_list_or_a_keyed_object_and_check_discards_the_body() {
+    let s = route_server(
+        "GET",
+        "/subscriptions/steps",
+        json!([
+            { "id": "auth.login-or-register", "dependencies": [] },
+            { "id": "payment_method", "dependencies": ["auth.login-or-register"] }
+        ]),
+    )
+    .await;
+    let steps = client(&s).subscription_steps().await.unwrap();
+    assert_eq!(steps.len(), 2);
+    assert_eq!(steps[1].dependencies, ["auth.login-or-register"]);
+
+    // What a real 5.13.50 server sends: an object keyed by PHP class name.
+    let s = route_server(
+        "GET",
+        "/subscriptions/steps",
+        json!({
+            "App\\Livewire\\Login": { "id": "auth.login", "dependencies": [] },
+            "App\\Livewire\\Pay": { "id": "payment_method", "dependencies": ["auth.login"] }
+        }),
+    )
+    .await;
+    let mut steps = client(&s).subscription_steps().await.unwrap();
+    steps.sort_by(|a, b| a.id.cmp(&b.id));
+    assert_eq!(steps[0].id, "auth.login");
+    assert_eq!(steps[1].dependencies, ["auth.login"]);
+
+    let s = route_server("POST", "/subscriptions/steps/check", json!([])).await;
+    client(&s)
+        .check_subscription_steps(&json!({ "steps": "a,b" }))
+        .await
+        .unwrap();
+}
+
+#[tokio::test]
+async fn refresh_bank_accounts_ignores_the_meaningless_body() {
+    let s = route_server("POST", "/bank_integrations/refresh_accounts", json!({})).await;
+    client(&s).refresh_bank_accounts().await.unwrap();
+}
+
+#[tokio::test]
+async fn extras_validate_ids_and_surface_errors() {
+    let server = MockServer::start().await;
+    let c = client(&server);
+
+    // A `/` in an id stays inside one segment instead of retargeting the call.
+    let _ = c.check_client_vat("a/b").await;
+    let seen = server.received_requests().await.unwrap();
+    assert_eq!(seen[0].url.path(), "/clients/a%2Fb/check_vat");
+
+    assert!(matches!(
+        c.check_client_vat("..").await,
+        Err(Error::InvalidPathSegment(_))
+    ));
+    assert!(matches!(
+        c.remove_bank_account("").await,
+        Err(Error::InvalidPathSegment(_))
+    ));
+    assert!(matches!(
+        c.test_company_gateway("..").await,
+        Err(Error::InvalidPathSegment(_))
+    ));
+
+    Mock::given(method("POST"))
+        .and(path("/subscriptions/steps/check"))
+        .respond_with(ResponseTemplate::new(422).set_body_json(json!({
+            "message": "invalid",
+            "errors": { "steps": ["bad order"] }
+        })))
+        .mount(&server)
+        .await;
+    let err = c
+        .check_subscription_steps(&json!({ "steps": "b,a" }))
+        .await
+        .expect_err("an invalid step list is a 422");
+    assert!(
+        matches!(err, Error::Api { status, .. } if status == 422),
+        "{err:?}"
+    );
+}
+
+/// These are all `POST`s, and some start work on the server, so a 5xx must
+/// not be replayed.
+#[tokio::test]
+async fn extras_are_not_replayed_on_5xx() {
+    let server = MockServer::start().await;
+    Mock::given(method("POST"))
+        .and(path("/company_gateways/abc/import_customers"))
+        .respond_with(ResponseTemplate::new(500))
+        .mount(&server)
+        .await;
+
+    client(&server)
+        .with_retry_policy(quick_retry())
+        .import_company_gateway_customers("abc")
+        .await
+        .expect_err("a failed trigger must not be retried");
+    assert_eq!(server.received_requests().await.unwrap().len(), 1);
+}
+
+// --- password-protected actions -----------------------------------------
+
+extra_test!(
+    purge_client_returns_the_message,
+    "POST",
+    "/clients/abc/purge",
+    message(),
+    |c| c.purge_client("abc"),
+    |got| assert_eq!(got.message, "ok")
+);
+
+extra_test!(
+    merge_clients_names_the_survivor_first_and_returns_it,
+    "POST",
+    "/clients/keep/drop/merge",
+    json!({ "data": { "id": "keep" } }),
+    |c| c.merge_clients("keep", "drop"),
+    |got| assert_eq!(got.id.as_deref(), Some("keep"))
+);
+
+extra_test!(
+    merge_vendors_names_the_survivor_first_and_returns_it,
+    "POST",
+    "/vendors/keep/drop/merge",
+    json!({ "data": { "id": "keep" } }),
+    |c| c.merge_vendors("keep", "drop"),
+    |got| assert_eq!(got.id.as_deref(), Some("keep"))
+);
+
+extra_test!(
+    purge_company_returns_the_message,
+    "POST",
+    "/companies/purge/abc",
+    message(),
+    |c| c.purge_company("abc"),
+    |got| assert_eq!(got.message, "ok")
+);
+
+extra_test!(
+    purge_company_save_settings_returns_the_message,
+    "POST",
+    "/companies/purge_save_settings/abc",
+    message(),
+    |c| c.purge_company_save_settings("abc"),
+    |got| assert_eq!(got.message, "ok")
+);
+
+extra_test!(
+    invite_user_returns_the_message,
+    "POST",
+    "/users/abc/invite",
+    message(),
+    |c| c.invite_user("abc"),
+    |got| assert_eq!(got.message, "ok")
+);
+
+extra_test!(
+    new_user_template_is_a_get_returning_a_blank_user,
+    "GET",
+    "/users/create",
+    entity(),
+    |c| c.new_user_template(),
+    |got| assert_eq!(got.id.as_deref(), Some("abc"))
+);
+
+/// User purge answers 204 with no body, which must not be treated as a decode
+/// failure.
+#[tokio::test]
+async fn purge_user_accepts_an_empty_204() {
+    let server = MockServer::start().await;
+    Mock::given(method("POST"))
+        .and(path("/users/abc/purge"))
+        .respond_with(ResponseTemplate::new(204))
+        .expect(1)
+        .mount(&server)
+        .await;
+
+    client(&server).purge_user("abc").await.unwrap();
+}
+
+/// Both ids in a merge go through the same path protection, so neither can
+/// retarget the request.
+#[tokio::test]
+async fn merge_validates_both_ids() {
+    let server = MockServer::start().await;
+    let c = client(&server);
+
+    assert!(matches!(
+        c.merge_clients("..", "x").await,
+        Err(Error::InvalidPathSegment(_))
+    ));
+    assert!(matches!(
+        c.merge_clients("x", "").await,
+        Err(Error::InvalidPathSegment(_))
+    ));
+    assert!(matches!(
+        c.merge_vendors("x", "..").await,
+        Err(Error::InvalidPathSegment(_))
+    ));
+
+    let _ = c.merge_clients("a/b", "c?d").await;
+    let seen = server.received_requests().await.unwrap();
+    assert_eq!(seen.len(), 1, "only the escaped call may reach the server");
+    assert_eq!(seen[0].url.path(), "/clients/a%2Fb/c%3Fd/merge");
+}
+
+/// A destructive POST that may have been applied must never be replayed.
+#[tokio::test]
+async fn destructive_actions_are_not_replayed_on_5xx() {
+    let server = MockServer::start().await;
+    Mock::given(method("POST"))
+        .respond_with(ResponseTemplate::new(500))
+        .mount(&server)
+        .await;
+    let c = client(&server).with_retry_policy(quick_retry());
+
+    c.purge_client("abc").await.expect_err("500");
+    c.merge_clients("a", "b").await.expect_err("500");
+    c.purge_company("abc").await.expect_err("500");
+    c.purge_user("abc").await.expect_err("500");
+    assert_eq!(server.received_requests().await.unwrap().len(), 4);
+}
+
+/// The password reaches the server on these routes, and without one the
+/// header is simply absent.
+#[tokio::test]
+async fn the_api_password_is_sent_on_protected_actions() {
+    let server = route_server("POST", "/clients/abc/purge", message()).await;
+    client(&server)
+        .with_api_password("hunter2")
+        .unwrap()
+        .purge_client("abc")
+        .await
+        .unwrap();
+
+    let sent = &server.received_requests().await.unwrap()[0];
+    assert_eq!(sent.headers.get("X-API-PASSWORD").unwrap(), "hunter2");
+    assert!(sent.headers.get("X-API-PASSWORD-BASE64").is_none());
+}
+
+/// A password with a control character cannot be a header value. It used to be
+/// rejected with a misleading `InvalidToken`; it now goes out base64 encoded,
+/// under the header the server's middleware decodes. The cases cover each
+/// padding form (`==`, `=`, none).
+#[tokio::test]
+async fn a_password_with_a_control_character_goes_out_base64_encoded() {
+    for (password, expected) in [("\n", "Cg=="), ("a\n", "YQo="), ("a\nb", "YQpi")] {
+        let server = route_server("POST", "/clients/abc/purge", message()).await;
+        client(&server)
+            .with_api_password(password)
+            .expect("any password is accepted")
+            .purge_client("abc")
+            .await
+            .unwrap();
+
+        let sent = &server.received_requests().await.unwrap()[0];
+        assert_eq!(
+            sent.headers.get("X-API-PASSWORD-BASE64").unwrap(),
+            expected,
+            "password {password:?}"
+        );
+        assert!(
+            sent.headers.get("X-API-PASSWORD").is_none(),
+            "the plain header must not also be sent"
+        );
+    }
+}
+
+/// Non-ASCII text is a valid header value, so those passwords keep going out
+/// as `X-API-PASSWORD` exactly as before.
+#[tokio::test]
+async fn a_non_ascii_password_still_goes_out_as_the_plain_header() {
+    let server = route_server("POST", "/clients/abc/purge", message()).await;
+    client(&server)
+        .with_api_password("pässwörd")
+        .unwrap()
+        .purge_client("abc")
+        .await
+        .unwrap();
+
+    let sent = &server.received_requests().await.unwrap()[0];
+    assert_eq!(
+        sent.headers.get("X-API-PASSWORD").unwrap().as_bytes(),
+        "pässwörd".as_bytes()
+    );
+    assert!(sent.headers.get("X-API-PASSWORD-BASE64").is_none());
+}
+
+/// The base64 fallback is as secret as the password itself, so it must be
+/// redacted from `Debug` too.
+#[tokio::test]
+async fn debug_output_redacts_a_base64_password_too() {
+    let c = InvoiceNinjaClient::new("http://localhost/api/v1", "tok")
+        .unwrap()
+        .with_api_password("S3CRETpw\nX")
+        .unwrap();
+    let shown = format!("{c:?}");
+    assert!(!shown.contains("S3CRET"), "{shown}");
+    assert!(!shown.contains("UzNDUkVUcHcK"), "{shown}");
+    assert!(shown.contains("Sensitive"), "{shown}");
+}
+
+// --- activities, email history, previews --------------------------------
+
+extra_test!(
+    list_activities_decodes_the_transformer_shape,
+    "GET",
+    "/activities",
+    json!({ "data": [{
+        "id": "a1", "activity_type_id": "10", "client_id": "c1", "invoice_id": "",
+        "is_system": false, "notes": "", "ip": "127.0.0.1",
+        "created_at": 1792869488, "updated_at": 1792869488
+    }] }),
+    |c| c.list_activities(&ListParams::new()),
+    |got| {
+        assert_eq!(got.len(), 1);
+        assert_eq!(got[0].activity_type_id, "10");
+        assert_eq!(got[0].created_at, Some(1792869488));
+    }
+);
+
+/// The feed is a different shape: numeric type, labelled references.
+#[tokio::test]
+async fn activity_feed_asks_for_reactv2_and_decodes_labelled_references() {
+    let server = MockServer::start().await;
+    Mock::given(method("GET"))
+        .and(path("/activities"))
+        .and(query_param("reactv2", "1"))
+        .and(query_param("rows", "5"))
+        .respond_with(ResponseTemplate::new(200).set_body_json(json!({ "data": [{
+            "id": "7", "hashed_id": "h7", "activity_type_id": 10, "notes": "", "ip": "",
+            "created_at": 1792869488,
+            "user": { "label": "Ann", "hashed_id": "u1" },
+            "invoice": { "label": "0001", "hashed_id": "i1" },
+            "payment_amount": "5.00"
+        }] })))
+        .expect(1)
+        .mount(&server)
+        .await;
+
+    let feed = client(&server).activity_feed(Some(5)).await.unwrap();
+    assert_eq!(feed[0].activity_type_id, 10);
+    assert_eq!(feed[0].invoice.as_ref().unwrap().label, "0001");
+    assert!(feed[0].client.is_none());
+    assert_eq!(feed[0].extra["payment_amount"], "5.00");
+}
+
+#[tokio::test]
+async fn activity_feed_without_rows_sends_no_rows_parameter() {
+    let server = route_server("GET", "/activities", json!({ "data": [] })).await;
+    client(&server).activity_feed(None).await.unwrap();
+
+    let url = &server.received_requests().await.unwrap()[0].url;
+    assert!(
+        !url.query_pairs().any(|(k, _)| k == "rows"),
+        "the server picks its own default, got {url}"
+    );
+}
+
+/// The server tests for the key, not its value, so `rows: null` would count
+/// as given and `take(null)` would drop the limit.
+#[tokio::test]
+async fn entity_activity_omits_rows_unless_given() {
+    for (rows, expected) in [
+        (None, json!({ "entity": "client", "entity_id": "c1" })),
+        (
+            Some(3),
+            json!({ "entity": "client", "entity_id": "c1", "rows": 3 }),
+        ),
+    ] {
+        let server = route_server("POST", "/activities/entity", json!({ "data": [] })).await;
+        client(&server)
+            .entity_activity("client", "c1", rows)
+            .await
+            .unwrap();
+        let sent: serde_json::Value = server.received_requests().await.unwrap()[0]
+            .body_json()
+            .unwrap();
+        assert_eq!(sent, expected);
+    }
+}
+
+extra_test!(
+    add_activity_note_returns_the_activity,
+    "POST",
+    "/activities/notes",
+    json!({ "data": { "id": "a9", "notes": "called them" } }),
+    |c| c.add_activity_note("invoices", "i1", "called them"),
+    |got| assert_eq!(got.notes, "called them")
+);
+
+#[tokio::test]
+async fn download_activity_entity_returns_the_pdf_bytes() {
+    let server = MockServer::start().await;
+    Mock::given(method("GET"))
+        .and(path("/activities/download_entity/a1"))
+        .respond_with(ResponseTemplate::new(200).set_body_bytes(b"%PDF-1.4".to_vec()))
+        .expect(1)
+        .mount(&server)
+        .await;
+    assert_eq!(
+        client(&server)
+            .download_activity_entity("a1")
+            .await
+            .unwrap(),
+        b"%PDF-1.4"
+    );
+}
+
+#[tokio::test]
+async fn a_missing_activity_backup_is_an_api_error_not_a_decode_failure() {
+    let server = MockServer::start().await;
+    Mock::given(method("GET"))
+        .respond_with(
+            ResponseTemplate::new(404)
+                .set_body_json(json!({ "message": "No backup exists", "errors": {} })),
+        )
+        .mount(&server)
+        .await;
+    let err = client(&server)
+        .download_activity_entity("a1")
+        .await
+        .expect_err("404");
+    assert!(
+        matches!(err, Error::Api { status, .. } if status == 404),
+        "{err:?}"
+    );
+}
+
+extra_test!(
+    client_email_history_decodes_a_bare_array,
+    "POST",
+    "/emails/clientHistory/c1",
+    json!([{ "entity": "invoice", "events": [{ "event": "delivered" }] }]),
+    |c| c.client_email_history("c1"),
+    |got| assert_eq!(got[0]["events"][0]["event"], "delivered")
+);
+
+extra_test!(
+    entity_email_history_sends_entity_and_id,
+    "POST",
+    "/emails/entityHistory",
+    json!([]),
+    |c| c.entity_email_history("invoice", "i1"),
+    |got| assert!(got.is_empty())
+);
+
+/// Every preview returns raw bytes (a PDF), never decodes JSON, and is
+/// routed to its own path.
+#[tokio::test]
+async fn previews_return_bytes_from_their_own_routes() {
+    let routes = [
+        "/preview",
+        "/live_preview",
+        "/live_design",
+        "/preview/purchase_order",
+        "/live_preview/purchase_order",
+    ];
+    for route in routes {
+        let server = MockServer::start().await;
+        Mock::given(method("POST"))
+            .and(path(route))
+            .respond_with(ResponseTemplate::new(200).set_body_bytes(b"%PDF-1.4".to_vec()))
+            .expect(1)
+            .mount(&server)
+            .await;
+        let c = client(&server);
+        let body = json!({ "entity": "invoice", "entity_id": "-1" });
+        let got = match route {
+            "/preview" => c.preview(&body).await,
+            "/live_preview" => c.live_preview(&body).await,
+            "/live_design" => c.live_design(&body).await,
+            "/preview/purchase_order" => c.preview_purchase_order(&body).await,
+            _ => c.live_preview_purchase_order(&body).await,
+        };
+        assert_eq!(got.unwrap(), b"%PDF-1.4", "{route}");
+    }
+}
+
+#[tokio::test]
+async fn preview_html_asks_for_html_and_returns_text() {
+    let server = MockServer::start().await;
+    Mock::given(method("POST"))
+        .and(path("/preview"))
+        .and(query_param("html", "true"))
+        .respond_with(ResponseTemplate::new(200).set_body_string("<html>x</html>"))
+        .expect(1)
+        .mount(&server)
+        .await;
+    let html = client(&server)
+        .preview_html(&json!({ "entity": "invoice", "entity_id": "-1" }))
+        .await
+        .unwrap();
+    assert_eq!(html, "<html>x</html>");
+}
+
+/// Previews can be rejected with a JSON validation error rather than a PDF.
+#[tokio::test]
+async fn a_rejected_preview_keeps_the_validation_errors() {
+    let server = MockServer::start().await;
+    Mock::given(method("POST"))
+        .respond_with(ResponseTemplate::new(422).set_body_json(json!({
+            "message": "invalid data access",
+            "errors": { "design.design.body": ["bad twig"] }
+        })))
+        .mount(&server)
+        .await;
+    let err = client(&server).preview(&json!({})).await.expect_err("422");
+    assert!(
+        matches!(&err, Error::Api { errors, .. } if errors.contains_key("design.design.body")),
+        "{err:?}"
+    );
+}
+
+/// Adding a note appends every time, so a lost response must not be replayed.
+#[tokio::test]
+async fn notes_are_not_replayed_on_5xx() {
+    let server = MockServer::start().await;
+    Mock::given(method("POST"))
+        .respond_with(ResponseTemplate::new(500))
+        .mount(&server)
+        .await;
+    client(&server)
+        .with_retry_policy(quick_retry())
+        .add_activity_note("invoices", "i1", "x")
+        .await
+        .expect_err("500");
+    assert_eq!(server.received_requests().await.unwrap().len(), 1);
+}