Define Test Steps and Assessments

You can assess your model simulation by creating test step actions, transitions, and assessments in Test Sequence and Test Assessment blocks

Test Sequence and Test Assessment blocks use MATLAB^® as the action language. Steps and transitions can include strings, including string comparisons, as well as assessment statements, signal generation functions, and relational operators. For more information, see Test Assessment, Test Sequence, and Test Sequence Editor.

Assessment Statements

To verify simulation, stop simulation, and return verification results, use assessment statements.

Keyword	Description
verify	Evaluates a logical expression and returns a pass, fail, or untested result. You can use optional arguments to label results in the Test Manager and Diagnostic Viewer or return an error message if a verify statement fails.
assert	Evaluates a logical expression and stops simulation if the expression evaluates to false. You can use optional arguments to return an error message in the Test Manager or Diagnostic Viewer.

Temporal Operators

To create an expression that evaluates the simulation time, use temporal operators. Variables in signal conditions must be inputs, parameters, or constants in the Test Sequence block. You can use these temporal operators:

Operator	Description
et	The elapsed time of the test step. You can specify the unit of time. If you do not specify a unit of time, the elapsed time is returned in seconds.
t	The elapsed time of the simulation. You can specify the unit of time. If you do not specify a unit of time, the elapsed time is returned in seconds.
after	Returns true if the specified time has elapsed since the beginning of the current test step.
before	Returns true until the specified time has elapsed from the beginning of the current test step.
duration	Returns the elapsed time for which the specified condition has been true. The elapsed time resets when the test step is re-entered or when the specified condition is no longer true.

Transition Operators

To create expressions that evaluate signal events, use transition operators. To evaluate signal events, the signals must be inputs in the Test Sequence or Test Assessment block.

Operator	Description
hasChanged	Returns true if the specified signal changes in value since the beginning of the test step, and otherwise returns false.
hasChangedFrom	Returns true if the specified signal changes from the specified value to a different value, and otherwise returns false.
hasChangedTo	Returns true if the specified signal changes to the specified value, and otherwise returns false.

Signal Generation Functions

You can these functions in the Test Sequence block to create test signals, random number values, and natural exponents. You can use temporal operators with some signal generation functions. For more information, see Temporal Operators.

Note

Scaling, rounding, and other approximations of argument values can affect function outputs.

Function	Description
sin	Returns the sine of the input in radians.
cos	Returns the cosine of the input argument in radians.
square	Generates a square wave test signal.
sawtooth	Generates a sawtooth wave test signal.
triangle	Generates a triangle wave test signal
ramp	Returns the value of the input.
heaviside	Returns 0 when the input is less than or equal to 0, and otherwise returns 1.
exp	Returns the natural exponential function, $$e^x$$.
rand	Returns uniformly distributed pseudorandom values.
randn	Returns normally distributed pseudorandom values.
latch	Saves the value of the input and returns the saved value. Resets the saved value when the step exits and reevaluates when the step is next active.

Logical Operators

You can use logical connectives in actions, transitions, and assessments. In these examples, p and q represent Boolean signals or logical expressions.

Operation	Syntax	Description	Example
Negation	~p	not p	verify(~p)
Conjunction	p && q	p and q	verify(p && q)
Disjunction	p || q	p or q	verify(p || q)
Implication	~p || q	if p, q. Logically equivalent to implication p → q.	verify(~p || q)
Biconditional	(p && q) || (~p && ~q)	p and q, or not p and not q. Logically equivalent to biconditional p ↔ q.	verify((p && q) || (~p && ~q))

Relational Operators

You can use relational operators in actions, transitions, and assessments. In these examples, x and y represent numeric-type variables.

Using == or ~= operators in a verify statement returns a warning when comparing floating-point data. Consider the precision limitations associated with floating-point numbers when implementing verify statements. See Floating-Point Numbers. If you use floating-point data, consider defining a tolerance for the assessment. For example, instead of verify(x == 5), verify x within a tolerance of 0.001:

verify(abs(x-5) < 0.001)

Operator and Syntax	Description	Example
x > y	Greater than	verify(x > y)
x < y	Less than	verify(x < y)
x >= y	Greater than or equal to	verify(x >= y)
x <= y	Less than or equal to	verify(x <= y)
x == y	Equal to	verify(x == y)
x ~= y	Not equal to	verify(x ~= y)