MATLAB Programming Fundamentals - MathWorks

assertWithRelTol(cosApprox,1)

%% Test pi over 4 equality

% Test sine and cosine of pi/4 are equal

[sinApprox,cosApprox] = approxSinCos(pi/4);

assertWithRelTol(sinApprox,cosApprox,'sine and cosine should be equal')

%% Test matches MATLAB fcn

% Test values of 2pi/3 match MATLAB output for the sin and cos functions

x = 2*pi/3;

[sinApprox,cosApprox] = approxSinCos(x);

assertWithRelTol(sinApprox,sin(x),'sin does not match')

assertWithRelTol(cosApprox,cos(x),'cos does not match')

function assertWithAbsTol(actVal,expVal,varargin)

% Helper function to assert equality within an absolute tolerance.

% Takes two values and an optional message and compares

% them within an absolute tolerance of 1e-6.

tol = 1e-6;

tf = abs(actVal-expVal) <= tol;

assert(tf, varargin{:});

end

function assertWithRelTol(actVal,expVal,varargin)

% Helper function to assert equality within a relative tolerance.

% Takes two values and an optional message and compares

% them within a relative tolerance of 0.1%.

relTol = 0.001;

tf = abs(expVal - actVal) <= relTol.*abs(expVal);

assert(tf, varargin{:});

end

Each unit test uses assert to check different output of the approxSinCos function.

Typically, when you compare floating-point values, you specify a tolerance for the

comparison. The local functions assertWithAbsTol and assertWithRelTol are helper

functions to compute whether the actual and expected values are equal within the

specified absolute or relative tolerance.

• Test 0rad tests whether the computed and expected values for an angle of 0 radians
  are within an absolute tolerance of 1e-6 or a relative tolerance 0.1%. Typically, you
  use absolute tolerance to compare values close to 0.

33 Unit Testing