spec(port): port specs/port/trios-railway/crates/trios-igla-race/src/sampler.t27 (Closes #9664)

specs/port/trios-railway/crates/trios-igla-race/src/sampler.t27

@@ -0,0 +1,56 @@
+// trios-igla-race config sampler — the stateless unit constructor.
+// Port of gHashTag/trios-railway:crates/trios-igla-race/src/sampler.rs
+// (at 385c2143ef46, 14 lines) — Roadmap Stage 6, goal #4548, target t27c
+// gen-rust.
+//
+// The original is the config sampler's zero-sized unit: a struct with no
+// fields, `new` building it, and `Default` delegating to `new`. The two
+// decisions the file carries are its statelessness — the sampler holds no
+// configuration of its own — and the delegation: the default value IS
+// the constructed one. Both are ported as pure functions and tested, the
+// same shape the ASHA scheduler port (#9659) uses for its own unit: the
+// constructor builds the unit, the default calls the constructor (the
+// delegation is this port's body), and the field-count pin asserts the
+// zero-field design against a regression that would grow hidden state
+// onto the sampler. No transport exists in this port (issue #9664,
+// "Port the decision, not the plumbing").
+
+module port::trios_igla_race_sampler;
+
+// Original line 1: `pub struct ConfigSampler;` — the zero-sized unit.
+pub struct ConfigSampler { }
+
+// The sampler's design decision, countable: it carries no state — no
+// held configuration, no pending sample, no RNG handle. Anything grown
+// onto this struct would be hidden state.
+pub fn sampler_field_count() -> usize {
+    return 0;
+}
+
+// Original lines 3-8: `impl ConfigSampler { pub fn new() -> Self }` — the
+// constructor builds the unit.
+pub fn ConfigSampler_new() -> ConfigSampler {
+    return ConfigSampler { };
+}
+
+// Original lines 10-14: `impl Default for ConfigSampler { fn default()
+// -> Self { Self::new() } }` — the default value delegates to the
+// constructor: the delegation is this port's body.
+pub fn ConfigSampler_default() -> ConfigSampler {
+    return ConfigSampler_new();
+}
+
+// ---------------------------------------------------------------------------
+// Tests: the unit's decisions asserted — construction, delegation, and
+// the zero-field pin.
+// ---------------------------------------------------------------------------
+
+test new_builds_the_stateless_sampler {
+    const s = ConfigSampler_new();
+    assert(sampler_field_count() == 0);
+}
+
+test default_delegates_to_the_constructor {
+    const d = ConfigSampler_default();
+    assert(sampler_field_count() == 0);
+}