1 files changed, 20 insertions, 0 deletions
diff --git a/test/domains/box-test.ts b/test/domains/box-test.ts
new file mode 100644
index 0000000..cb930a0
--- /dev/null
+++ b/test/domains/box-test.ts
@@ -0,0 +1,20 @@
+import { test, describe } from "node:test";
+import assert from "node:assert/strict";
+import { centreOf } from "../../src/domains/box";
+
+describe("box centre", () => {
+  test("computes the centre from a content quad", () => {
+    const b = centreOf({ content: [10, 20, 110, 20, 110, 70, 10, 70], width: 100, height: 50 });
+    assert.equal(b.cx, 60);
+    assert.equal(b.cy, 45);
+    assert.equal(b.width, 100);
+    assert.equal(b.height, 50);
+  });
+
+  test("a degenerate zero-size quad yields its own corner, not NaN", () => {
+    const b = centreOf({ content: [5, 5, 5, 5, 5, 5, 5, 5], width: 0, height: 0 });
+    assert.equal(b.cx, 5);
+    assert.equal(b.cy, 5);
+    assert.ok(!Number.isNaN(b.cx));
+  });
+});