Function generate 

pub fn generate<F>(count: usize, seed: u64, element_factory: F) -> String
where
    F: FnMut(&mut Rng) -> String,

Generate a JSON array of count elements. Each element is produced by element_factory(rng) and embedded verbatim in the array (the factory MUST return valid JSON).

Example

use dev_fixtures::mock::{json_array::generate, Rng};
let json = generate(3, 7, |rng| {
    format!("{{\"id\": {}}}", rng.range(1000))
});
assert!(json.starts_with("["));
assert!(json.ends_with("]"));