big cmap refactoring

test/cmap-history.test.mjs

@@ -0,0 +1,48 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+
+import { CmapHistory } from "../static/cmap/controller/cmap-history.js";
+
+function history(initial = "one") {
+  let value = initial;
+  const changes = [];
+  const instance = new CmapHistory({
+    snapshot: () => value,
+    restore: (snapshot) => { value = snapshot; },
+    onChange: (change) => changes.push(change),
+    limit: 2
+  });
+  return {
+    instance,
+    changes,
+    get value() { return value; },
+    set value(next) { value = next; }
+  };
+}
+
+test("CmapHistory commits, undoes and redoes serialized state", () => {
+  const state = history();
+  state.instance.reset();
+  state.value = "two";
+  assert.equal(state.instance.commit(), true);
+  state.value = "three";
+  assert.equal(state.instance.commit(), true);
+
+  assert.equal(state.instance.undo(), true);
+  assert.equal(state.value, "two");
+  assert.equal(state.instance.redo(), true);
+  assert.equal(state.value, "three");
+  assert.equal(state.instance.canUndo(), true);
+  assert.equal(state.instance.canRedo(), false);
+});
+
+test("CmapHistory replaces a document as one undo operation", () => {
+  const state = history();
+  state.instance.reset();
+  state.instance.replace(() => { state.value = "replacement"; });
+
+  assert.equal(state.value, "replacement");
+  assert.equal(state.instance.undo(), true);
+  assert.equal(state.value, "one");
+  assert.ok(state.changes.length > 0);
+});