T25a Generative: prompt and settings

PromptEnhancer offers a fuller prompt with the words it adds washed,
split at punctuation; Use this takes it into the field, Keep mine
lets it go. StylePresetPicker and AspectRatioPicker are rows of Tab
stops, the chosen one in accent; a ratio chip draws its shape.
SeedInput keeps digits up to u32::MAX and rolls one with a die.
NegativePromptInput and ImageGenerationPanel point to forms::TagInput
and forms::Form. theme.generative() holds the chapter's sizes. The
gallery's preset pictures are the atrium photo in five styles.

src/generative/tests/mod.rs

@@ -0,0 +1,216 @@
+use std::{cell::RefCell, rc::Rc};
+
+use gpui::{
+    AppContext as _, Context, Entity, IntoElement, KeyBinding, KeyUpEvent, Keystroke,
+    ParentElement, Render, SharedString, Styled, TestAppContext, VisualTestContext, Window, div,
+    px,
+};
+
+use crate::{
+    forms::{self, TextInput},
+    generative::{AspectRatioPicker, PromptEnhancer, SeedInput, StylePreset, StylePresetPicker},
+    primitives::FocusNext,
+    theme::Theme,
+};
+
+fn settle(cx: &mut VisualTestContext) {
+    cx.run_until_parked();
+    cx.update(|window, _| window.refresh());
+    cx.run_until_parked();
+}
+
+/// Presses and releases `key`, a frame apart.
+fn press(key: &str, cx: &mut VisualTestContext) {
+    cx.simulate_keystrokes(key);
+    settle(cx);
+    cx.simulate_event(KeyUpEvent {
+        keystroke: Keystroke::parse(key).expect("a key"),
+    });
+    settle(cx);
+}
+
+fn tab(times: usize, cx: &mut VisualTestContext) {
+    for _ in 0..times {
+        cx.update(|window, _| window.focus_next());
+    }
+}
+
+fn setup(cx: &mut TestAppContext) {
+    cx.update(|cx| {
+        Theme::init(cx);
+        forms::bind_keys(cx);
+        cx.bind_keys([KeyBinding::new("tab", FocusNext, None)]);
+    });
+}
+
+/// A prompt with its enhancer, a suggestion the test sets, and what it heard.
+struct Enhancing {
+    field: Entity<TextInput>,
+    suggestion: Option<SharedString>,
+    heard: Vec<String>,
+}
+
+impl Render for Enhancing {
+    fn render(&mut self, _: &mut Window, cx: &mut Context<Self>) -> impl IntoElement {
+        let (asked, resolved) = (cx.entity(), cx.entity());
+        let enhancer = PromptEnhancer::new("enhancer", &self.field)
+            .on_enhance(move |prompt, _, cx| {
+                asked.update(cx, |view, _| view.heard.push(format!("asked {prompt}")))
+            })
+            .on_resolve(move |taken, _, cx| {
+                resolved.update(cx, |view, _| {
+                    view.heard.push(format!("taken {taken}"));
+                    view.suggestion = None;
+                })
+            });
+        let enhancer = match &self.suggestion {
+            Some(text) => enhancer.suggestion(text.clone()),
+            None => enhancer,
+        };
+        div().w(px(420.0)).child(enhancer)
+    }
+}
+
+fn enhancing(cx: &mut TestAppContext) -> (Entity<Enhancing>, &mut VisualTestContext) {
+    setup(cx);
+    let (view, cx) = cx.add_window_view(|window, cx| Enhancing {
+        field: cx.new(|cx| TextInput::new(window, cx)),
+        suggestion: None,
+        heard: Vec::new(),
+    });
+    cx.update(|window, _| window.activate_window());
+    settle(cx);
+    (view, cx)
+}
+
+#[gpui::test]
+fn enhance_asks_with_the_trimmed_prompt_and_use_this_takes_the_offer(cx: &mut TestAppContext) {
+    let (view, cx) = enhancing(cx);
+    tab(1, cx);
+    cx.simulate_input("  a cat  ");
+    tab(1, cx);
+    press("enter", cx);
+    view.update(cx, |view, cx| {
+        view.suggestion = Some("a fluffy cat asleep".into());
+        cx.notify();
+    });
+    settle(cx);
+    tab(1, cx);
+    press("enter", cx);
+    view.read_with(cx, |view, cx| {
+        assert_eq!(view.heard, ["asked a cat", "taken true"]);
+        assert_eq!(view.field.read(cx).text(), "a fluffy cat asleep");
+    });
+}
+
+#[gpui::test]
+fn keep_mine_leaves_the_prompt_as_written(cx: &mut TestAppContext) {
+    let (view, cx) = enhancing(cx);
+    tab(1, cx);
+    cx.simulate_input("a cat");
+    view.update(cx, |view, cx| {
+        view.suggestion = Some("a fluffy cat".into());
+        cx.notify();
+    });
+    settle(cx);
+    tab(3, cx);
+    press("enter", cx);
+    view.read_with(cx, |view, cx| {
+        assert_eq!(view.heard, ["taken false"]);
+        assert_eq!(view.field.read(cx).text(), "a cat");
+    });
+}
+
+/// Three presets, two ratios, a seed, and every pick heard.
+struct Picks {
+    seed: Entity<TextInput>,
+    style: SharedString,
+    heard: Rc<RefCell<Vec<String>>>,
+}
+
+impl Render for Picks {
+    fn render(&mut self, _: &mut Window, _: &mut Context<Self>) -> impl IntoElement {
+        let (styled, shaped) = (self.heard.clone(), self.heard.clone());
+        let preset = |key: &str| StylePreset {
+            key: key.to_string().into(),
+            name: key.to_string().into(),
+            picture: None,
+        };
+        div()
+            .w(px(420.0))
+            .child(
+                StylePresetPicker::new(
+                    "styles",
+                    [preset("a"), preset("b"), preset("c")],
+                    self.style.clone(),
+                )
+                .on_select(move |key, _, _| styled.borrow_mut().push(format!("style {key}"))),
+            )
+            .child(
+                AspectRatioPicker::new("ratios", [(1, 1), (4, 3)], (1, 1)).on_select(
+                    move |ratio, _, _| {
+                        shaped
+                            .borrow_mut()
+                            .push(format!("ratio {}:{}", ratio.0, ratio.1))
+                    },
+                ),
+            )
+            .child(SeedInput::new("seed", &self.seed))
+    }
+}
+
+fn picks(
+    cx: &mut TestAppContext,
+) -> (
+    Entity<Picks>,
+    Rc<RefCell<Vec<String>>>,
+    &mut VisualTestContext,
+) {
+    setup(cx);
+    let heard = Rc::new(RefCell::new(Vec::new()));
+    let store = heard.clone();
+    let (view, cx) = cx.add_window_view(|window, cx| Picks {
+        seed: cx.new(|cx| TextInput::new(window, cx)),
+        style: "a".into(),
+        heard: store,
+    });
+    cx.update(|window, _| window.activate_window());
+    settle(cx);
+    (view, heard, cx)
+}
+
+#[gpui::test]
+fn tabs_reach_each_tile_and_chip_and_enter_picks_it(cx: &mut TestAppContext) {
+    let (_, heard, cx) = picks(cx);
+    tab(1, cx);
+    press("enter", cx);
+    tab(1, cx);
+    press("enter", cx);
+    tab(3, cx);
+    press("enter", cx);
+    assert_eq!(
+        *heard.borrow(),
+        ["style b", "ratio 4:3"],
+        "the chosen tile stays quiet"
+    );
+}
+
+#[gpui::test]
+fn a_seed_keeps_digits_and_the_die_rolls_one(cx: &mut TestAppContext) {
+    let (view, _, cx) = picks(cx);
+    tab(6, cx);
+    cx.simulate_input("12a3");
+    view.read_with(cx, |view, cx| {
+        assert_eq!(SeedInput::read(&view.seed, cx), Some(123))
+    });
+    tab(1, cx);
+    press("enter", cx);
+    view.read_with(cx, |view, cx| {
+        let text = view.seed.read(cx).text().to_string();
+        assert_ne!(text, "123", "the die rolls a new seed");
+        assert_eq!(
+            SeedInput::read(&view.seed, cx).map(|seed| seed.to_string()),
+            Some(text)
+        );
+    });
+}