test: add the behavioral spec suites (pilot + ten domains)

98 tests pinning observable behavior ahead of the authorship rewrite.

tests/Feature/PilotSpec/SetDomainTest.php

@@ -0,0 +1,53 @@
+<?php
+
+// Pilot behavioural suite — the domain step and environment-file editing rules.
+// Spec: platform-operations-spec.md §3 (domain step, environment-file editing).
+// These tests edit the real environment file and restore it afterwards.
+
+use function Pest\Laravel\putJson;
+
+beforeEach(function () {
+    Artisan::call('db:seed', ['--class' => 'DatabaseSeeder', '--force' => true]);
+    $this->envBackup = file_get_contents(base_path('.env'));
+});
+
+afterEach(function () {
+    file_put_contents(base_path('.env'), $this->envBackup);
+});
+
+it('requires a domain', function () {
+    putJson('/api/v1/installation/set-domain', [])->assertStatus(422);
+});
+
+it('always writes the session domain as the host portion of the submitted value', function () {
+    config(['app.url' => 'http://pilot.test']);
+
+    putJson('/api/v1/installation/set-domain', ['app_domain' => 'http://other.test'])
+        ->assertOk()
+        ->assertJson(['success' => true]);
+
+    $env = file_get_contents(base_path('.env'));
+    expect($env)->toContain('SESSION_DOMAIN=other.test');
+});
+
+it('writes the stateful-domains entry when the submitted domain differs from the current one', function () {
+    config(['app.url' => 'http://pilot.test']);
+
+    putJson('/api/v1/installation/set-domain', ['app_domain' => 'elsewhere.test'])->assertOk();
+
+    $env = file_get_contents(base_path('.env'));
+    expect($env)->toContain('SANCTUM_STATEFUL_DOMAINS=elsewhere.test');
+    expect($env)->toContain('SESSION_DOMAIN=elsewhere.test');
+});
+
+it('replaces an existing key in place rather than appending a duplicate', function () {
+    config(['app.url' => 'http://pilot.test']);
+
+    putJson('/api/v1/installation/set-domain', ['app_domain' => 'first.test'])->assertOk();
+    putJson('/api/v1/installation/set-domain', ['app_domain' => 'second.test'])->assertOk();
+
+    $env = file_get_contents(base_path('.env'));
+    expect(substr_count($env, "\nSESSION_DOMAIN=") + (str_starts_with($env, 'SESSION_DOMAIN=') ? 1 : 0))
+        ->toBe(1);
+    expect($env)->toContain('SESSION_DOMAIN=second.test');
+});