Add buffer packer tests

src/export/packer/buffer.spec.ts

@@ -0,0 +1,44 @@
+/* tslint:disable:typedef space-before-function-paren */
+import { assert } from "chai";
+import { stub } from "sinon";
+
+import { BufferPacker } from "../../export/packer/buffer";
+import { File, Paragraph } from "../../file";
+
+describe.only("BufferPacker", () => {
+    let packer: BufferPacker;
+
+    beforeEach(() => {
+        const file = new File({
+            creator: "Dolan Miu",
+            revision: "1",
+            lastModifiedBy: "Dolan Miu",
+        });
+        const paragraph = new Paragraph("test text");
+        const heading = new Paragraph("Hello world").heading1();
+        file.addParagraph(new Paragraph("title").title());
+        file.addParagraph(heading);
+        file.addParagraph(new Paragraph("heading 2").heading2());
+        file.addParagraph(paragraph);
+
+        packer = new BufferPacker(file);
+    });
+
+    describe("#pack()", () => {
+        it("should create a standard docx file", async function() {
+            this.timeout(99999999);
+            const buffer = await packer.pack();
+            assert.isDefined(buffer);
+            assert.isTrue(buffer.byteLength > 0);
+        });
+
+        it("should handle exception if it throws any", () => {
+            // tslint:disable-next-line:no-any
+            const compiler = stub((packer as any).packer, "compile");
+            compiler.throwsException();
+            return packer.pack().catch((error) => {
+                assert.isDefined(error);
+            });
+        });
+    });
+});