Add unit tests for viewport focus

tests/unit/viewport-focus.test.ts

@@ -0,0 +1,117 @@
+import { describe, expect, it } from "vitest";
+
+import { createBoxBrush } from "../../src/document/brushes";
+import { createEmptySceneDocument } from "../../src/document/scene-document";
+import { createPlayerStartEntity } from "../../src/entities/entity-instances";
+import { resolveViewportFocusTarget } from "../../src/viewport-three/viewport-focus";
+
+describe("resolveViewportFocusTarget", () => {
+  it("frames the selected brush", () => {
+    const brush = createBoxBrush({
+      id: "brush-room",
+      center: {
+        x: 3,
+        y: 2,
+        z: -1
+      },
+      size: {
+        x: 6,
+        y: 4,
+        z: 2
+      }
+    });
+    const document = {
+      ...createEmptySceneDocument(),
+      brushes: {
+        [brush.id]: brush
+      }
+    };
+
+    expect(
+      resolveViewportFocusTarget(document, {
+        kind: "brushes",
+        ids: [brush.id]
+      })
+    ).toEqual({
+      center: {
+        x: 3,
+        y: 2,
+        z: -1
+      },
+      radius: Math.hypot(6, 4, 2) * 0.5
+    });
+  });
+
+  it("frames the owning brush when a face is selected", () => {
+    const brush = createBoxBrush({
+      id: "brush-face-room"
+    });
+    const document = {
+      ...createEmptySceneDocument(),
+      brushes: {
+        [brush.id]: brush
+      }
+    };
+
+    const focusTarget = resolveViewportFocusTarget(document, {
+      kind: "brushFace",
+      brushId: brush.id,
+      faceId: "posZ"
+    });
+
+    expect(focusTarget?.center).toEqual(brush.center);
+    expect(focusTarget?.radius).toBe(Math.hypot(2, 2, 2) * 0.5);
+  });
+
+  it("frames the selected Player Start helper", () => {
+    const playerStart = createPlayerStartEntity({
+      id: "entity-player-start-main",
+      position: {
+        x: 4,
+        y: 0,
+        z: -2
+      },
+      yawDegrees: 90
+    });
+    const document = {
+      ...createEmptySceneDocument(),
+      entities: {
+        [playerStart.id]: playerStart
+      }
+    };
+
+    const focusTarget = resolveViewportFocusTarget(document, {
+      kind: "entities",
+      ids: [playerStart.id]
+    });
+
+    expect(focusTarget?.center).toEqual({
+      x: 4,
+      y: 0.3,
+      z: -2
+    });
+    expect(focusTarget?.radius).toBeGreaterThan(0.6);
+  });
+
+  it("frames the authored scene when nothing is selected and returns null when the scene is empty", () => {
+    const brush = createBoxBrush({
+      id: "brush-room"
+    });
+    const populatedDocument = {
+      ...createEmptySceneDocument(),
+      brushes: {
+        [brush.id]: brush
+      }
+    };
+
+    expect(resolveViewportFocusTarget(populatedDocument, { kind: "none" })).toEqual({
+      center: {
+        x: 0,
+        y: 1,
+        z: 0
+      },
+      radius: Math.hypot(2, 2, 2) * 0.5
+    });
+    expect(resolveViewportFocusTarget(createEmptySceneDocument(), { kind: "none" })).toBeNull();
+  });
+});