1 files changed, 33 insertions, 0 deletions
diff --git a/packages/utils/test-utils.ts b/packages/utils/test-utils.ts
new file mode 100644
index 0000000..1dfd14c
--- /dev/null
+++ b/packages/utils/test-utils.ts
@@ -0,0 +1,33 @@
+import { diffStringsUnified } from "jest-diff";
+
+expect.extend({
+  toCloselyEqualPoints(received, expected, precision) {
+    if (!Array.isArray(received) || !Array.isArray(expected)) {
+      throw new Error("expected and received are not point arrays");
+    }
+
+    const COMPARE = 1 / Math.pow(10, precision || 2);
+    const pass = expected.every(
+      (point, idx) =>
+        Math.abs(received[idx]?.[0] - point[0]) < COMPARE &&
+        Math.abs(received[idx]?.[1] - point[1]) < COMPARE,
+    );
+
+    if (!pass) {
+      return {
+        message: () => ` The provided array of points are not close enough.
+
+${diffStringsUnified(
+  JSON.stringify(expected, undefined, 2),
+  JSON.stringify(received, undefined, 2),
+)}`,
+        pass: false,
+      };
+    }
+
+    return {
+      message: () => `expected ${received} to not be close to ${expected}`,
+      pass: true,
+    };
+  },
+});