Function beforeAll

beforeAll<T>(fn): void
Run some shared setup before all of the tests in the group. Useful for async setup in describe blocks. Outside them, top-level initialization code should be used instead.
Type Parameters
- T
  The self type of the function
Parameters
- fn: ((this: T) => void | Promise<void>)
  The function to implement the setup behavior.
  - - (this): void | Promise<void>
    - Parameters
      this: T
      Returns void | Promise<void>
Returns void
Example: Usage
```
import { describe, it, beforeAll } from "@std/testing/bdd";
import { assertEquals } from "@std/assert";

beforeAll(() => {
 console.log("beforeAll");
});

describe("example", () => {
  it("should pass", () => {
    // test case
    assertEquals(2 + 2, 4);
  });
});
```
- Defined in testing/bdd.ts:864