forgefixture: the bench actuator's firmware

An ESP32-S3 DevKitC-1 on the bench network drives three relays at the
machine's connectors so the acceptance tool can open the lid loop, pull
the interlock loop and press the button with nobody in the room. Two
contacts are normally closed in loops the safety chain already reads,
the third is normally open across the button input and only ever
pulsed (20 to 500 ms, the end armed before the line rises); every line
is low at boot and after any reset, the task watchdog panics and
reboots, and the button channel needs a jumper. HTTP on port 80 under
a key in X-Fixture-Key; the hostname announced over DHCP and mDNS.

ESP-IDF v5.5 native, the mDNS component pinned in dependencies.lock;
fixture.env (git-ignored) is the one input: the wifi, the key, the
hostname. fixture.sh builds with idf.py or in the espressif/idf
container, flashes with esptool from pip. The decisions that need no
hardware live in policy.c with a gcc host test; CI runs it and builds
the firmware in the pinned container.

fixture/test/policy_test.c

@@ -0,0 +1,73 @@
+/*
+ * forgefixture policy, held to account on the host: gcc -o policy_test
+ * policy_test.c ../main/policy.c (see run.sh).
+ *
+ * (C) Copyright 2026
+ * Scott Wiederhold, s.e.wiederhold@gmail.com
+ * SPDX-License-Identifier: MIT
+ */
+#include <stdio.h>
+#include <string.h>
+
+#include "../main/policy.h"
+
+static int failures;
+
+#define CHECK(cond) do { if (!(cond)) { failures++; printf("FAIL %s:%d: %s\n", __FILE__, __LINE__, #cond); } } while (0)
+
+int main(void)
+{
+    /* names and paths */
+    CHECK(strcmp(policy_channel_name(CH_LID), "lid") == 0);
+    CHECK(strcmp(policy_channel_name(CH_INTERLOCK), "interlock") == 0);
+    CHECK(strcmp(policy_channel_name(CH_BUTTON), "button") == 0);
+    CHECK(policy_channel_from_path("/lid") == CH_LID);
+    CHECK(policy_channel_from_path("/interlock") == CH_INTERLOCK);
+    CHECK(policy_channel_from_path("/button") == CH_BUTTON);
+    CHECK(policy_channel_from_path("/lids") == -1);
+    CHECK(policy_channel_from_path("lid") == -1);
+    CHECK(policy_channel_from_path(NULL) == -1);
+
+    /* a loop request: open energizes, close/closed releases, nothing else */
+    bool e = false;
+    CHECK(policy_parse_loop_state("open", &e) && e);
+    CHECK(policy_parse_loop_state("close", &e) && !e);
+    CHECK(policy_parse_loop_state("closed", &e) && !e);
+    CHECK(!policy_parse_loop_state("Open", &e));
+    CHECK(!policy_parse_loop_state("on", &e));
+    CHECK(!policy_parse_loop_state("", &e));
+    CHECK(!policy_parse_loop_state(NULL, &e));
+
+    /* the button pulse: a default, a floor, a ceiling, never a hold */
+    CHECK(policy_button_ms(0) == BUTTON_DEFAULT_MS);
+    CHECK(policy_button_ms(-5) == BUTTON_DEFAULT_MS);
+    CHECK(policy_button_ms(1) == BUTTON_MIN_MS);
+    CHECK(policy_button_ms(250) == 250);
+    CHECK(policy_button_ms(500) == BUTTON_MAX_MS);
+    CHECK(policy_button_ms(501) == BUTTON_MAX_MS);
+    CHECK(policy_button_ms(60000) == BUTTON_MAX_MS);
+    CHECK(BUTTON_MAX_MS <= 500);
+
+    /* state names */
+    CHECK(strcmp(policy_state_name(CH_LID, true), "open") == 0);
+    CHECK(strcmp(policy_state_name(CH_LID, false), "closed") == 0);
+    CHECK(strcmp(policy_state_name(CH_INTERLOCK, true), "open") == 0);
+    CHECK(strcmp(policy_state_name(CH_BUTTON, true), "pressed") == 0);
+    CHECK(strcmp(policy_state_name(CH_BUTTON, false), "idle") == 0);
+
+    /* the key: exact, whole, and never by prefix */
+    CHECK(policy_key_matches("abc123", "abc123"));
+    CHECK(!policy_key_matches("abc12", "abc123"));
+    CHECK(!policy_key_matches("abc1234", "abc123"));
+    CHECK(!policy_key_matches("", "abc123"));
+    CHECK(!policy_key_matches("abc123", ""));
+    CHECK(!policy_key_matches(NULL, "abc123"));
+    CHECK(!policy_key_matches("ABC123", "abc123"));
+
+    if (failures) {
+        printf("%d failure(s)\n", failures);
+        return 1;
+    }
+    printf("policy: all checks passed\n");
+    return 0;
+}

fixture/test/run.sh

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+#!/bin/sh
+# The host test of the fixture's policy: needs only a C compiler.
+set -e
+cd "$(dirname "$0")"
+${CC:-cc} -std=c11 -Wall -Wextra -Werror -o policy_test policy_test.c ../main/policy.c
+./policy_test