Fix trailing-history (take implementation from guidemaker) to properly

app/locations/trailing-history.js

@@ -1,16 +1,18 @@
 import HistoryLocation from '@ember/routing/history-location';
 
-/* When using this location type with ember-cli dev server, be sure to 
+/* When using this location type with ember-cli dev server, be sure to
    set historySupportMiddleware: true in config/environment.js */
 
-export default class extends HistoryLocation {
+export default class TrailingHistoryLocation extends HistoryLocation {
   formatURL() {
-    let url = super.formatURL(...arguments);
+    return formatURL(super.formatURL(...arguments));
+  }
+}
 
-    if (url.includes('#')) {
-      return url.replace(/([^/])#(.*)/, '$1/#$2');
-    } else {
-      return url.replace(/\/?$/, '/');
-    }
+export function formatURL(url) {
+  let parsed = new URL(url, 'http://example.com');
+  if (!parsed.pathname.endsWith('/')) {
+    parsed.pathname += '/';
   }
+  return `${parsed.pathname}${parsed.search}${parsed.hash}`;
 }

tests/unit/locations/trailing-history-test.js

@@ -0,0 +1,46 @@
+import { module, test } from 'qunit';
+import { formatURL } from 'ember-api-docs/locations/trailing-history';
+
+module('Unit | Location | trailing-history | formatURL', function () {
+  const cases = [
+    {
+      input: '/ember/6.8/classes/Ember.Controller',
+      output: '/ember/6.8/classes/Ember.Controller/',
+      label: 'adds trailing slash to bare path',
+    },
+    {
+      input: '/ember/6.8/classes/Ember.Controller/',
+      output: '/ember/6.8/classes/Ember.Controller/',
+      label: 'leaves already-trailing-slashed path unchanged',
+    },
+    {
+      input: '/ember/6.8/classes/Ember.Controller?show=deprecated',
+      output: '/ember/6.8/classes/Ember.Controller/?show=deprecated',
+      label: 'adds trailing slash before query string',
+    },
+    {
+      input: '/ember/6.8/classes/Ember.Controller?show=deprecated#addObserver',
+      output:
+        '/ember/6.8/classes/Ember.Controller/?show=deprecated#addObserver',
+      label: 'adds trailing slash before query string, preserving hash',
+    },
+    {
+      input: '/ember/6.8/classes/Ember.Controller#addObserver',
+      output: '/ember/6.8/classes/Ember.Controller/#addObserver',
+      label: 'adds trailing slash before hash when no query string',
+    },
+    {
+      input: '/ember/6.8/classes/Ember.Controller/?show=deprecated#addObserver',
+      output:
+        '/ember/6.8/classes/Ember.Controller/?show=deprecated#addObserver',
+      label:
+        'leaves already-trailing-slashed path with query and hash unchanged',
+    },
+  ];
+
+  for (let { input, output, label } of cases) {
+    test(label, function (assert) {
+      assert.strictEqual(formatURL(input), output);
+    });
+  }
+});