group

Learn test organization with group.

Organization with group

group('name', () { ... }) gathers related tests. For example you place the tests of a MathUtils class inside group('MathUtils', () { ... }).

Groups organize test output; each test appears with its group name. This makes large test files easy to read.

Groups can nest. group('Math', () { group('factorial', () { ... }); }) creates a subgroup.

Nested groups

Groups can nest. For example group('Math', () { group('factorial', () { test('zero', () {}); }); }) builds a hierarchy. The output shows Math factorial zero.

Inner groups inherit the outer group's context. A setUp defined in the outer group also runs for the inner group's tests.

But very deep nesting hurts readability. Two levels are usually enough.

Exercise MathUtils and factorial

Define a MathUtils class with a static int factorial(int n) method. If n <= 1 return 1, otherwise return n * factorial(n - 1). In main print MathUtils.factorial(5) with print.

Show example solution

class MathUtils {
  static int factorial(int n) {
    if (n <= 1) return 1;
    return n * factorial(n - 1);
  }
}

void main() {
  print(MathUtils.factorial(5));
}

Test yourself

The group block

group('MathUtils', ____ { test('toplama', () {}); });

Show answer

group('MathUtils', () { test('toplama', () {}); });

What does group do?
- Throws an error
- Sets up a loop
- Groups related tests
- Opens a file
Show answer

Groups related tests — group gathers related tests together.
group parts

group('Math', () {})

Outer group
group('factorial', () {})

Inner group
test('zero', () {})

Test

Next lesson: setUp and tearDown

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