Add Math Summation

src/file/paragraph/math/n-ary/math-sub-script.spec.ts

@@ -0,0 +1,27 @@
+import { expect } from "chai";
+
+import { Formatter } from "export/formatter";
+
+import { MathRun } from "../math-run";
+import { MathSubScript } from "./math-sub-script";
+
+describe("MathSubScript", () => {
+    describe("#constructor()", () => {
+        it("should create a MathSubScript with correct root key", () => {
+            const mathSubScript = new MathSubScript(new MathRun("2+2"));
+
+            const tree = new Formatter().format(mathSubScript);
+            expect(tree).to.deep.equal({
+                "m:sub": [
+                    {
+                        "m:r": [
+                            {
+                                "m:t": ["2+2"],
+                            },
+                        ],
+                    },
+                ],
+            });
+        });
+    });
+});