docs(components): correct the documented component count

crates/rustmotion-components/Cargo.toml

@@ -2,7 +2,7 @@
 name = "rustmotion-components"
 version.workspace = true
 edition = "2021"
-description = "Component library for rustmotion (51 components)"
+description = "Component library for rustmotion (60 components)"
 license = "MIT"
 repository = "https://github.com/LeadcodeDev/rustmotion"
 readme = "../../README.md"

crates/rustmotion-core/tests/audit_ws_k.rs

@@ -0,0 +1,90 @@
+//! Regression tests for the workstream K (docs, schema, CI) audit findings:
+//! documentation drift and inert schema fields.
+
+/// Text immediately following the component count in the README's
+/// Architecture section (see `README.md`'s "rustmotion ships N components,
+/// each implementing the `Painter` trait" sentence).
+const README_COUNT_MARKER: &str = " components, each implementing the `Painter` trait";
+
+/// Text immediately following the component count in
+/// `crates/rustmotion-components/Cargo.toml`'s `description` — the string
+/// crates.io displays for the published crate.
+const CARGO_TOML_COUNT_MARKER: &str = " components)\"";
+
+/// Read the integer that appears immediately before `marker` in `haystack`,
+/// skipping trailing whitespace. Panics with the marker text on failure so a
+/// reworded sentence names exactly what moved instead of a bare parse error.
+fn number_before(haystack: &str, marker: &str, haystack_name: &str) -> u32 {
+    let idx = haystack.find(marker).unwrap_or_else(|| {
+        panic!(
+            "marker {marker:?} not found in {haystack_name} — did the component count sentence \
+             move or get reworded? Update this test's marker to match."
+        )
+    });
+    let digits: String = haystack[..idx]
+        .chars()
+        .rev()
+        .skip_while(|c| c.is_whitespace())
+        .take_while(|c| c.is_ascii_digit())
+        .collect();
+    let digits: String = digits.chars().rev().collect();
+    digits.parse().unwrap_or_else(|_| {
+        panic!("no number found immediately before marker {marker:?} in {haystack_name}")
+    })
+}
+
+/// Count the variants of `pub enum Component` in
+/// `crates/rustmotion-components/src/lib.rs`, by counting non-empty,
+/// non-attribute lines between its opening `{` and closing `}`. Every
+/// variant in that enum is declared on its own line (`Name(Type),`); the
+/// only other lines in the block are `#[serde(...)]` attributes.
+fn count_component_variants(lib_rs: &str) -> usize {
+    let start_marker = "pub enum Component {";
+    let start = lib_rs.find(start_marker).unwrap_or_else(|| {
+        panic!("{start_marker:?} not found in rustmotion-components/src/lib.rs")
+    }) + start_marker.len();
+    let rest = &lib_rs[start..];
+    let end = rest
+        .find("\n}")
+        .expect("no closing '}' found for `pub enum Component` block");
+    let body = &rest[..end];
+    body.lines()
+        .map(str::trim)
+        .filter(|line| !line.is_empty() && !line.starts_with('#'))
+        .count()
+}
+
+/// README.md and `rustmotion-components/Cargo.toml` (the text
+/// crates.io shows for the published crate) both claimed "51 components"
+/// while `Component` actually had 60 variants — and nothing kept the two in
+/// sync. Locks the documented counts to the real one so a future component
+/// addition/removal that forgets to update the docs fails CI instead of
+/// drifting silently again.
+#[test]
+fn documented_component_count_matches_enum_variant_count() {
+    let lib_rs = include_str!("../../rustmotion-components/src/lib.rs");
+    let actual = count_component_variants(lib_rs);
+    assert!(
+        actual > 0,
+        "found zero variants in `pub enum Component` — count parsing is broken"
+    );
+
+    let readme = include_str!("../../../README.md");
+    let readme_count = number_before(readme, README_COUNT_MARKER, "README.md");
+    assert_eq!(
+        readme_count as usize, actual,
+        "README.md claims {readme_count} components but `Component` has {actual} variants"
+    );
+
+    let cargo_toml = include_str!("../../rustmotion-components/Cargo.toml");
+    let cargo_toml_count = number_before(
+        cargo_toml,
+        CARGO_TOML_COUNT_MARKER,
+        "rustmotion-components/Cargo.toml",
+    );
+    assert_eq!(
+        cargo_toml_count as usize, actual,
+        "rustmotion-components/Cargo.toml's description claims {cargo_toml_count} components but \
+         `Component` has {actual} variants"
+    );
+}