Feature/math improve (#2976)

* add new feature

* add test file

* update test file

* update test file

* Fix linting

---------

Co-authored-by: Dolan Miu <dolan_miu@hotmail.com>

src/file/paragraph/math/bar/math-bar.spec.ts

@@ -0,0 +1,38 @@
+import { describe, expect, it } from "vitest";
+
+import { Formatter } from "@export/formatter";
+
+import { MathBar } from "./math-bar";
+import { MathRun } from "../math-run";
+
+describe("MathBar", () => {
+    describe("#constructor()", () => {
+        it("should create a MathBar with correct root key", () => {
+            const mathBar = new MathBar({ type: "top", children: [new MathRun("text")] });
+            const tree = new Formatter().format(mathBar);
+
+            expect(tree).to.deep.equal({
+                "m:bar": [
+                    {
+                        "m:barPr": [
+                            {
+                                "m:pos": {
+                                    _attr: {
+                                        "w:val": "top",
+                                    },
+                                },
+                            },
+                        ],
+                    },
+                    {
+                        "m:e": [
+                            {
+                                "m:r": [{ "m:t": ["text"] }],
+                            },
+                        ],
+                    },
+                ],
+            });
+        });
+    });
+});