You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: test_curl.m
    path of file: ./repos/chebfun/tests/spherefunv
    
    the code of the file until where you have to start completion: function pass = test_curl( ) 
% Test curl

tol = 2e3*chebfunpref().cheb2Prefs.chebfun2eps;

% Check curl of an empty spherefunv is an empty spherefunv.
u = spherefunv;
f = curl(u);
pass(1) = isempty(f) & isa(f,'spherefunv');

% Check curl of a spherefunv is a spherefunv.
u = spherefunv.unormal;
f = curl(u);
pass(2) = isa(f,'spherefunv');

% Check curl of the zero field is zero
f = spherefun(@(x,y,z) 0*x);
u = spherefunv(f,f,f);
pass(3) = norm(curl(u)) < tol; 

%
% Check curl of a non-zero field gives the correct result
%

% Example 1
f = spherefun(@(x,y,z) x);
g = spherefun(@(x,y,z) y);
h = spherefun(@(x,y,z) z);
u = spherefunv(f,g,h);
curlu = curl(u);
% Exact curl is zero
exact = spherefun(@(x,y,z) 0*x, @(x,y,z) 0*x, @(x,y,z) 0*x);
pass(4) = norm(curlu-exact) < tol; 

% Example 2
f = spherefun(@(x,y,z) cos(4*y));

    
function pass = test_curl( ) 
% Test curl

tol = 2e3*chebfunpref().cheb2Prefs.chebfun2eps;

% Check curl of an empty spherefunv is an empty spherefunv.
u = spherefunv;
f = curl(u);
pass(1) = isempty(f) & isa(f,'spherefunv');

% Check curl of a spherefunv is a spherefunv.
u = spherefunv.unormal;
f = curl(u);
pass(2) = isa(f,'spherefunv');

% Check curl of the zero field is zero
f = spherefun(@(x,y,z) 0*x);
u = spherefunv(f,f,f);
pass(3) = norm(curl(u)) < tol; 

%
% Check curl of a non-zero field gives the correct result
%

% Example 1
f = spherefun(@(x,y,z) x);
g = spherefun(@(x,y,z) y);
h = spherefun(@(x,y,z) z);
u = spherefunv(f,g,h);
curlu = curl(u);
% Exact curl is zero
exact = spherefun(@(x,y,z) 0*x, @(x,y,z) 0*x, @(x,y,z) 0*x);
pass(4) = norm(curlu-exact) < tol; 

% Example 2
f = spherefun(@(x,y,z) cos(4*y));
g = spherefun(@(x,y,z) cos(4*z));
h = spherefun(@(x,y,z) sin(4*x));
u = spherefunv(f,g,h);
curlu = curl(u);
% Exact curl
f = spherefun(@(x,y,z) -4*x.*y.*cos(4*x)+4*(1-z.^2).*sin(4*z));
g = spherefun(@(x,y,z) 4*y.*z.*sin(4*y)-4*(1-x.^2).*cos(4*x));
h = spherefun(@(x,y,z) 4*x.*z.*sin(4*z)+4*(1-y.^2).*sin(4*y));
exact = spherefunv(f,g,h);
pass(5) = norm(curlu-exact) < 100*tol; 

end