Learn C++ Online

This lesson contains approximately 45 minutes of video content.

Unit tests

Writing unit tests in C++ with the Catch2 framework

We will use the Catch2 framework unit testing framework in our class. To learn how to compose unit tests using this framework, please see the Catch2 framework for authoring test cases page under our site's Resources section. You will be required to write test cases using this framework for assessments in this course. Therefore, you can either become familiar with it today or once the first assignment requiring it is released.

Coverage measurement

Test-driven development

Beyond correctness

Questions

QTDD Q1

This question is ungraded.

What are unit tests? Select the best answer.

Automated tests that determine if independently developed units of software work correctly when connected together.

Automated tests that exercise and evaluate individual units of source code.

Mystical creatures from a galaxy far-far away!

Non-automated tests that help determine if your code works correctly.

Practice question: try as many times as you like

QTDD Q2

This question is ungraded.

A given code contains an if-else statement. The test suite for this portion of code contains two tests:

one that traverses the if branch, and
one that traverses the else branch.

What coverage level is satisfied by this test suite?

C0

C1

S0

S1

Practice question: try as many times as you like

QTDD Q3

This question is ungraded.

What kind(s) of tests with 100% coverage, guarantee bug-free code:

C0 (statement coverage)
C1 (conditionals coverage)
C2 (paths coverage)
DU-coverage (all pairs of define X/use X for every variable X)

Select the best answer.

A and B

A, B, C, and D

C by itself

No combination of those tests guarantee bug-free code.

Practice question: try as many times as you like

QTDD Q4

This question is ungraded.

Which of the following is NOT true? Select the best answer.

Print statements are frequently used in conventional debugging but not in TDD.

TDD allows for tests to be re-run automatically

TDD is more productive than conventional debugging due to FIRST

Writing tests before code in TDD takes more time up-front, leading to more time overall, compared to conventional debugging

Practice question: try as many times as you like

QTDD Q5

This question is ungraded.

Why are boolean arguments a yellow flag? Select the best answer.

Boolean arguments are NOT a yellow flag.

Boolean arguments are almost always unnecessary.

Boolean arguments result in arguments that travel in a pack.

If a function behaves differently based on a boolean argument, there should probably be 2 different functions.

Practice question: try as many times as you like

QTDD Q6

This question is ungraded.

What should you do if arguments "travel in a pack"?

Create a new type containing all of the arguments.

Eliminate some of the arguments.

Nothing, this is not an issue or problem.

Unpack the arguments.

Practice question: try as many times as you like

QTDD Q7

This question is ungraded.

The two pieces of code that follow have the same logical functionality but different structure. Which statement about them is TRUE?

Version 1.

void foo(bool x, bool y) {
  if (x) {
    if (y) z();    
  }      
  else {       
    if (y) w();    
  }      
}

Version 2.

void check_y_z(bool val);
void check_y_w(bool val);

void def foo(bool x, bool y) {              
  if (x) {
    check_y_z(y);
  }
  else {
    check_y_w(y);                     
  }
}

void check_y_z(bool val) {
  if (val) z();
}

void check_y_w(bool val) {
  if (val) w(); 
}

Version 1 cannot be tested to 100% C2 coverage.

Version 1 has higher **per-function** cyclomatic complexity than Version 2.

Version 2 cannot be tested to 100% C2 coverage.

Practice question: try as many times as you like