From 6ec259a0e71174651bae95d4628138bf6fd68742 Mon Sep 17 00:00:00 2001
From: kj_sh604
Date: Sun, 15 Mar 2026 16:19:35 -0400
Subject: refactor: packages/

---
 packages/math/range.test.ts | 51 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)
 create mode 100644 packages/math/range.test.ts

(limited to 'packages/math/range.test.ts')

diff --git a/packages/math/range.test.ts b/packages/math/range.test.ts
new file mode 100644
index 0000000..fb4b6a3
--- /dev/null
+++ b/packages/math/range.test.ts
@@ -0,0 +1,51 @@
+import { rangeInclusive, rangeIntersection, rangesOverlap } from "./range";
+
+describe("range overlap", () => {
+  const range1_4 = rangeInclusive(1, 4);
+
+  it("should overlap when range a contains range b", () => {
+    expect(rangesOverlap(range1_4, rangeInclusive(2, 3))).toBe(true);
+    expect(rangesOverlap(range1_4, range1_4)).toBe(true);
+    expect(rangesOverlap(range1_4, rangeInclusive(1, 3))).toBe(true);
+    expect(rangesOverlap(range1_4, rangeInclusive(2, 4))).toBe(true);
+  });
+
+  it("should overlap when range b contains range a", () => {
+    expect(rangesOverlap(rangeInclusive(2, 3), range1_4)).toBe(true);
+    expect(rangesOverlap(rangeInclusive(1, 3), range1_4)).toBe(true);
+    expect(rangesOverlap(rangeInclusive(2, 4), range1_4)).toBe(true);
+  });
+
+  it("should overlap when range a and b intersect", () => {
+    expect(rangesOverlap(range1_4, rangeInclusive(2, 5))).toBe(true);
+  });
+});
+
+describe("range intersection", () => {
+  const range1_4 = rangeInclusive(1, 4);
+
+  it("should intersect completely with itself", () => {
+    expect(rangeIntersection(range1_4, range1_4)).toEqual(range1_4);
+  });
+
+  it("should intersect irrespective of order", () => {
+    expect(rangeIntersection(range1_4, rangeInclusive(2, 3))).toEqual([2, 3]);
+    expect(rangeIntersection(rangeInclusive(2, 3), range1_4)).toEqual([2, 3]);
+    expect(rangeIntersection(range1_4, rangeInclusive(3, 5))).toEqual(
+      rangeInclusive(3, 4),
+    );
+    expect(rangeIntersection(rangeInclusive(3, 5), range1_4)).toEqual(
+      rangeInclusive(3, 4),
+    );
+  });
+
+  it("should intersect at the edge", () => {
+    expect(rangeIntersection(range1_4, rangeInclusive(4, 5))).toEqual(
+      rangeInclusive(4, 4),
+    );
+  });
+
+  it("should not intersect", () => {
+    expect(rangeIntersection(range1_4, rangeInclusive(5, 7))).toEqual(null);
+  });
+});
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