lib.lists.foldl': Add tests

      };

    };

  testFoldl'Empty = {

    expr = foldl' (acc: el: abort "operation not called") 0 [ ];

    expected = 0;

  };

  testFoldl'IntegerAdding = {

    expr = foldl' (acc: el: acc + el) 0 [ 1 2 3 ];

    expected = 6;

  };

  # The accumulator isn't forced deeply

  testFoldl'NonDeep = {

    expr = take 3 (foldl'

      (acc: el: [ el ] ++ acc)

      [ (abort "unevaluated list entry") ]

      [ 1 2 3 ]);

    expected = [ 3 2 1 ];

  };

  # The same as builtins.foldl', lib.foldl' doesn't evaluate the first accumulator strictly

  testFoldl'StrictInitial = {

    expr = (builtins.tryEval (foldl' (acc: el: el) (throw "hello") [])).success;

    expected = true;

  };

  # Make sure we don't get a stack overflow for large lists

  # This number of elements would notably cause a stack overflow if it was implemented without the `foldl'` builtin

  testFoldl'Large = {

    expr = foldl' (acc: el: acc + el) 0 (range 0 100000);

    expected = 5000050000;

  };

  testTake = testAllTrue [

    ([] == (take 0 [  1 2 3 ]))

    ([1] == (take 1 [  1 2 3 ]))