Summary - Testing
- Dart course
- Intermediate
- Lesson 87/116
- 5 min
Combine test, expect and mock to write a calculator test.
Summary: Testing
In this group you saw the dart test framework, test and expect, organization with group, fixtures with setUp/tearDown and mocks. Tests guarantee your code's correctness.
Now we combine them: we will write a testable Calculator class and print its result. This is the cornerstone of testing.
Remember: each test probes one behavior; setUp builds a clean environment; mocks keep external dependencies out.
Practice Calculator: add and subtract
Define a Calculator class with int add(int a, int b) => a + b; and int subtract(int a, int b) => a - b; methods. In main print the results of add(10, 3) and subtract(10, 3) on separate lines with print.
Starter code
// Define the Calculator class (add, subtract)
void main() {
// print the results of add(10, 3) and subtract(10, 3)
}Sample solution
class Calculator {
int add(int a, int b) => a + b;
int subtract(int a, int b) => a - b;
}
void main() {
var c = Calculator();
print(c.add(10, 3));
print(c.subtract(10, 3));
}Expected output
13 7
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 Concept matching
| Term | Meaning |
|---|---|
test() |
Test block |
expect() |
Assertion |
group() |
Organization |
setUp() |
Fixture |
2 What does setUp provide?
- Throws an error
- A clean fixture Correct answer
- Sets up a loop
- Creates a mock
Explanation: setUp provides a clean fixture.
3 The expect matcher
expect(result, ____(5));expect(result, equals(5));Explanation: equals(5) states the expected value.