refactor(kanban): render test board payload with hemplate

Replace the Kanban generated-slot unit test's inline raw HTML board payload with a hemplate-rendered view and DOM-aware assertion.

req: html_safety/002

req: view/001

req: test/005

examples/kanban/src/lib.rs

@@ -4,17 +4,48 @@ pub mod ui {}
 #[cfg(test)]
 mod tests {
     use super::ui;
-    use slhx::{IntoEffect, SafeHtml};
+    use hemplate::Hemplate;
+    use scraper::{Html, Selector};
+    use slhx::{Effect, IntoEffect, Payload, SafeHtml};
     use slhx_test::inspect;
 
+    #[derive(Hemplate)]
+    #[hemplate = "partials"]
+    struct BoardColumns {
+        columns: Vec<String>,
+    }
+
     // req: examples/001 req: codegen/002 req: list/003
     #[test]
     fn kanban_board_updates_generated_slot() {
         fn render_board() -> impl IntoEffect {
-            ui::board::slots::board.html(SafeHtml::trusted("<div class=\"columns\"></div>"))
+            ui::board::slots::board.html(render_empty_board())
         }
 
-        assert!(inspect(render_board()).has_slot(ui::board::slots::board));
+        let effect = inspect(render_board());
+        assert!(effect.has_slot(ui::board::slots::board));
+        assert!(matches!(effect.ops(), [Effect::Put { payload: Payload::Html(_), .. }]));
+    }
+
+    // req: html_safety/002 req: view/001 req: test/005
+    #[test]
+    fn kanban_board_test_payload_is_rendered_by_a_hemplate_view() {
+        let html = render_empty_board();
+        let document = Html::parse_fragment(html.as_str());
+        assert_eq!(document.select(&selector(".columns")).count(), 1);
+    }
+
+    fn render_empty_board() -> SafeHtml {
+        // req: html_safety/002 req: view/001
+        SafeHtml::trusted(
+            BoardColumns { columns: Vec::new() }
+                .render()
+                .expect("kanban board test view renders"),
+        )
+    }
+
+    fn selector(value: &str) -> Selector {
+        Selector::parse(value).expect("test selector parses")
     }
 
     // req: examples/001 req: form/002 req: codegen/003