matlab.unittest.constraints.ReturnsTrue class

Package: matlab.unittest.constraints
Superclasses: matlab.unittest.constraints.Constraint

Constraint specifying function handle that returns true

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Construction

ReturnsTrue provides a constraint specifying that a function handle that returns true. The constraint is satisfied only by a function handle that returns a scalar logical with a value of true.

Copy Semantics

Handle. To learn how handle classes affect copy operations, see Copying Objects.

Examples

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These comparisons are shown for example only. There are other constraints that might better handle the particular comparisons.

Create a test case for interactive testing.

import matlab.unittest.TestCase
import matlab.unittest.constraints.ReturnsTrue

testCase = TestCase.forInteractiveUse;

Verify that the ReturnsTrue constraint is satisfied by the value returned by a handle to true. 

testCase.verifyThat(@true, ReturnsTrue)
Interactive verification passed.

Verify that the ReturnsTrue constraint is not satisfied by a handle to false. 

testCase.verifyThat(@false, ReturnsTrue)
Interactive verification failed.

---------------------
Framework Diagnostic:
---------------------
ReturnsTrue failed.
--> The function handle should have evaluated to "true".
--> Returned value:
             0

Actual Function Handle:
        @false

Verify that a call to isequal returns true.

testCase.verifyThat(@() isequal(1,1), ReturnsTrue)
Interactive verification passed.

Verify that a function that returns a double-valued 1 does not satisfy the ReturnsTrue constraint.

testCase.verifyThat(@() double(true), ReturnsTrue)
Interactive verification failed.

---------------------
Framework Diagnostic:
---------------------
ReturnsTrue failed.
--> The function handle should have returned a logical value. It was of type "double".
--> Returned value:
             1

Actual Function Handle:
        @()double(true)

Verify that the negation of a text comparison of 'a' and 'b' returns true.

testCase.verifyThat(@() ~strcmp('a','b'), ReturnsTrue)
Interactive verification passed.

Test if a comparison of 'a' to the cell array {'a','a'} returns true.

testCase.verifyThat(@() strcmp('a',{'a','a'}), ReturnsTrue)
Interactive verification failed.

---------------------
Framework Diagnostic:
---------------------
ReturnsTrue failed.
--> The function handle should have returned a scalar. The return value had a size of [1  2].
--> Returned value:
             1     1

Actual Function Handle:
        @()strcmp('a',{'a','a'})

The constraint is not satisfied because the call to strcmp results a logical array, not a logical scalar.

Tips

  • To display custom comparisons in the form of a function handle, use ReturnsTrue instead of IsTrue.

See Also

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