add test

smart-entities/utils/cos_sim.test.js

@@ -0,0 +1,72 @@
+/**
+ * @file cos_sim.test.js
+ * @description Unit tests for the cos_sim function using AVA.
+ */
+
+import test from 'ava';
+import { cos_sim } from './cos_sim.js';
+
+/**
+ * @description Tests whether cos_sim calculates the correct cosine similarity 
+ * for two identical vectors (positive integers).
+ */
+test('cos_sim: identical vectors, positive integers', t => {
+  const vector_one = [1, 2, 3];
+  const vector_two = [1, 2, 3];
+  const result = cos_sim(vector_one, vector_two);
+  t.is(result, 1, 'Cosine similarity of identical vectors should be 1');
+});
+
+/**
+ * @description Tests whether cos_sim calculates the correct cosine similarity 
+ * for vectors with both positive and negative values (allows for floating-point rounding).
+ */
+test('cos_sim: mixed sign vectors', t => {
+  const vector_one = [1, -1, 2];
+  const vector_two = [2, -1, 1];
+
+  const result = cos_sim(vector_one, vector_two);
+
+  // Expected = 5/6 = 0.8333333333...
+  const expected = 5 / 6;
+  const epsilon = 1e-12;
+
+  t.true(
+    Math.abs(result - expected) < epsilon,
+    `Cosine similarity of [1, -1, 2] and [2, -1, 1] should be close to ${expected} (got ${result})`
+  );
+});
+
+/**
+ * @description Tests whether cos_sim returns 0 when one or both vectors
+ * have an extremely small magnitude (e.g. zero vector).
+ */
+test('cos_sim: zero vector should return 0', t => {
+  const vector_one = [0, 0, 0];
+  const vector_two = [1, 2, 3];
+  const result = cos_sim(vector_one, vector_two);
+  t.is(result, 0, 'Cosine similarity with zero vector should be 0');
+});
+
+/**
+ * @description Tests that cos_sim throws an error when vectors have different lengths.
+ */
+test('cos_sim: throws error with different lengths', t => {
+  const vector_one = [1, 2];
+  const vector_two = [1, 2, 3];
+  const error = t.throws(() => {
+    cos_sim(vector_one, vector_two);
+  });
+  t.is(error.message, 'Vectors must have the same length');
+});
+
+/**
+ * @description Tests for floating-point precision and correct handling.
+ */
+test('cos_sim: floating point precision check', t => {
+  const vector_one = [0.1, 0.2, 0.3];
+  const vector_two = [0.1, 0.2, 0.3];
+  const result = cos_sim(vector_one, vector_two);
+  // Ideally close to 1, some floating-point error is acceptable
+  t.true(Math.abs(result - 1) < 1e-12, 'Cosine similarity should be very close to 1 for nearly identical vectors');
+});