matlab.unittest.constraints.HasElementCount Class

Namespace: matlab.unittest.constraints
Superclasses: `matlab.unittest.constraints.BooleanConstraint`

Test if array has specified number of elements

Description

The `matlab.unittest.constraints.HasElementCount` class provides a constraint to test if an array has the specified element count.

Creation

Description

example

````c = matlab.unittest.constraints.HasElementCount(count)` creates a constraint to test if an array has the specified element count and sets the `Count` property. The constraint is satisfied if the number of array elements is equal to `count`.```

Properties

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Expected element count, returned as a nonnegative integer scalar. Specify the value of this property during creation of the constraint.

Attributes:

 `GetAccess` `public` `SetAccess` `private`

Data Types: `double` | `single` | `int8` | `int16` | `int32` | `int64` | `uint8` | `uint16` | `uint32` | `uint64`

Examples

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Test for numbers of array elements using the `HasElementCount` constraint.

First, import the classes used in this example.

```import matlab.unittest.TestCase import matlab.unittest.constraints.HasElementCount```

Create a test case for interactive testing.

`testCase = TestCase.forInteractiveUse;`

Verify that a scalar has an element count of one.

`testCase.verifyThat(3,HasElementCount(1))`
`Verification passed.`

Verify that the matrix `[1 2 3; 4 5 6]` does not have three elements.

`testCase.verifyThat([1 2 3; 4 5 6],~HasElementCount(3))`
`Verification passed.`

Verify that an identity matrix has the expected number of elements.

```n = 7; testCase.verifyThat(eye(n),HasElementCount(n^2))```
`Verification passed.`

Test the element count of a cell array of character vectors. The test passes.

```C = {'Mercury','Gemini','Apollo'}; testCase.verifyThat(C,HasElementCount(3))```
`Verification passed.`

Test the element count of a scalar structure with two fields. The test fails because the structure has only one element.

```s.field1 = 1; s.field2 = zeros(1,10); testCase.verifyThat(s,HasElementCount(2))```
```Verification failed. --------------------- Framework Diagnostic: --------------------- HasElementCount failed. --> The value did not have the correct number of elements. Actual Number of Elements: 1 Expected Number of Elements: 2 Actual Value: struct with fields: field1: 1 field2: [0 0 0 0 0 0 0 0 0 0]```

Version History

Introduced in R2013a