chore: establish learning module baseline

OpenMAIC/tests/pbl/v2/fit-scale.test.ts

@@ -0,0 +1,85 @@
+import { describe, expect, it } from 'vitest';
+
+import { computeFitScale } from '@/components/scene-renderers/pbl/v2/fit-scale';
+
+describe('PBL v2 — computeFitScale', () => {
+  it('keeps natural size (1) when the content already fits', () => {
+    expect(
+      computeFitScale({
+        containerWidth: 1280,
+        containerHeight: 720,
+        contentWidth: 640,
+        contentHeight: 500,
+      }),
+    ).toBe(1);
+  });
+
+  it('never scales up content that is smaller than the box', () => {
+    expect(
+      computeFitScale({
+        containerWidth: 1280,
+        containerHeight: 720,
+        contentWidth: 100,
+        contentHeight: 100,
+      }),
+    ).toBe(1);
+  });
+
+  it('shrinks by the height ratio when the content is too tall (the Hero zoom bug)', () => {
+    // Box shorter than the content → scale down so the bottom (launch button)
+    // stays visible instead of being clipped by overflow-hidden.
+    expect(
+      computeFitScale({
+        containerWidth: 800,
+        containerHeight: 400,
+        contentWidth: 640,
+        contentHeight: 800,
+      }),
+    ).toBe(0.5);
+  });
+
+  it('shrinks by the width ratio when the content is too wide', () => {
+    expect(
+      computeFitScale({
+        containerWidth: 320,
+        containerHeight: 720,
+        contentWidth: 640,
+        contentHeight: 360,
+      }),
+    ).toBe(0.5);
+  });
+
+  it('uses the smaller ratio when both axes overflow', () => {
+    // width ratio 0.5, height ratio 0.25 → must pick 0.25 so both fit.
+    expect(
+      computeFitScale({
+        containerWidth: 320,
+        containerHeight: 200,
+        contentWidth: 640,
+        contentHeight: 800,
+      }),
+    ).toBe(0.25);
+  });
+
+  it('falls back to 1 for unmeasured / degenerate dimensions', () => {
+    expect(
+      computeFitScale({ containerWidth: 0, containerHeight: 0, contentWidth: 0, contentHeight: 0 }),
+    ).toBe(1);
+    expect(
+      computeFitScale({
+        containerWidth: 800,
+        containerHeight: 600,
+        contentWidth: 0,
+        contentHeight: 400,
+      }),
+    ).toBe(1);
+    expect(
+      computeFitScale({
+        containerWidth: Number.NaN,
+        containerHeight: 600,
+        contentWidth: 400,
+        contentHeight: 400,
+      }),
+    ).toBe(1);
+  });
+});