fix: Document title with slashes produces folders in exported zip file

closes #2036

server/utils/fs.test.js

@@ -0,0 +1,34 @@
+// @flow
+import { serializeFilename, deserializeFilename } from "./fs";
+
+describe("serializeFilename", () => {
+  it("should serialize forward slashes", () => {
+    expect(serializeFilename(`/`)).toBe("%2F");
+    expect(serializeFilename(`this / and / this`)).toBe(
+      "this %2F and %2F this"
+    );
+  });
+
+  it("should serialize back slashes", () => {
+    expect(serializeFilename(`\\`)).toBe("%5C");
+    expect(serializeFilename(`this \\ and \\ this`)).toBe(
+      "this %5C and %5C this"
+    );
+  });
+});
+
+describe("deserializeFilename", () => {
+  it("should deserialize forward slashes", () => {
+    expect(deserializeFilename("%2F")).toBe("/");
+    expect(deserializeFilename("this %2F and %2F this")).toBe(
+      `this / and / this`
+    );
+  });
+
+  it("should deserialize back slashes", () => {
+    expect(deserializeFilename("%5C")).toBe(`\\`);
+    expect(deserializeFilename("this %5C and %5C this")).toBe(
+      `this \\ and \\ this`
+    );
+  });
+});