test(commands): cover viewport command flow

input/viewport.test.ts

@@ -0,0 +1,68 @@
+import { describe, expect, test } from "bun:test";
+import { createViewportPointerPanHandler, handleViewportWheel } from "./viewport";
+
+const ignoredState = undefined as never;
+
+describe("viewport input", () => {
+  test("wheel dispatches zoom around point", () => {
+    const dispatched: unknown[] = [];
+    const consumed = handleViewportWheel({
+      event: { position: { x: 10, y: 20 }, delta: { x: 0, y: -100 }, altKey: false, ctrlKey: false, metaKey: false, shiftKey: false },
+      globalConsumer: () => false,
+      currentZoom: 1,
+      dispatch: (commandId, payload) => {
+        dispatched.push({ commandId, payload });
+        return ignoredState;
+      },
+    });
+
+    expect(consumed).toBe(true);
+    expect(dispatched[0]).toEqual({ commandId: "viewport.zoomAroundPoint", payload: { zoom: Math.exp(0.1), point: { x: 10, y: 20 } } });
+  });
+
+  test("global wheel consumer prevents command dispatch", () => {
+    let called = false;
+    const consumed = handleViewportWheel({
+      event: { position: { x: 0, y: 0 }, delta: { x: 0, y: 1 }, altKey: false, ctrlKey: false, metaKey: false, shiftKey: false },
+      globalConsumer: () => true,
+      currentZoom: 1,
+      dispatch: () => {
+        called = true;
+        return ignoredState;
+      },
+    });
+
+    expect(consumed).toBe(true);
+    expect(called).toBe(false);
+  });
+
+  test("middle mouse drag dispatches viewport pan", () => {
+    const dispatched: unknown[] = [];
+    const pan = createViewportPointerPanHandler({
+      globalConsumer: () => false,
+      getCurrentZoom: () => 2,
+      dispatch: (commandId, payload) => {
+        dispatched.push({ commandId, payload });
+        return ignoredState;
+      },
+    });
+
+    expect(pan.pointerDown(basePointer({ buttons: 4, position: { x: 10, y: 10 } }))).toBe(true);
+    expect(pan.pointerMove(basePointer({ buttons: 4, position: { x: 14, y: 6 } }))).toBe(true);
+    expect(dispatched[0]).toEqual({ commandId: "viewport.pan", payload: { delta: { x: -2, y: 2 } } });
+  });
+});
+
+function basePointer(overrides: Partial<Parameters<ReturnType<typeof createViewportPointerPanHandler>["pointerDown"]>[0]> = {}) {
+  return {
+    pointerId: 1,
+    pointerType: "mouse" as const,
+    position: { x: 0, y: 0 },
+    buttons: 0,
+    altKey: false,
+    ctrlKey: false,
+    metaKey: false,
+    shiftKey: false,
+    ...overrides,
+  };
+}