chore(core): Port tests to ESM

packages/core/tests/snippet.test.mjs

@@ -0,0 +1,31 @@
+import chai from "chai"
+import freesewing from "./dist/index.mjs"
+
+const expect = chai.expect
+
+it("Should create a snippet", () => {
+  let snip1 = new freesewing.Snippet("test", new freesewing.Point(12, 34));
+  expect(snip1.def).to.equal("test");
+  expect(snip1.anchor.x).to.equal(12);
+  expect(snip1.anchor.y).to.equal(34);
+});
+
+it("Should clone a snippet", () => {
+  let snip3 = new freesewing.Snippet("boo", new freesewing.Point(56, 78));
+  expect(snip3.clone().def).to.equal("boo");
+  expect(snip3.clone().anchor.x).to.equal(56);
+  expect(snip3.clone().anchor.y).to.equal(78);
+});
+
+it("Should set an attribute", () => {
+  let s = new freesewing.Snippet("test", new freesewing.Point(12, -34)).attr(
+    "class",
+    "test"
+  );
+  expect(s.attributes.get("class")).to.equal("test");
+  s.attr("class", "more");
+  expect(s.attributes.get("class")).to.equal("test more");
+  s.attr("class", "less", true);
+  expect(s.attributes.get("class")).to.equal("less");
+});
+