Function describe 

pub fn describe(
    title: &str,
    description: &str,
    after_all_hook: fn(),
    after_each_hook: fn(),
    before_all_hook: fn(),
    before_each_hook: fn(),
    main: fn(Suite) -> Suite,
) -> Suite

Start a test suite

• description The test suite description
• after_all_hook A callback
• after_each_hook A callback
• before_all_hook A callback
• before_each_hook A callback
• main The main callback