Asynchronous Programming

Question 1

single process thread

Answer 1

synchronous

Question 2

multiple processes coordinating and running parallel with each other

Answer 2

asynchronous

Question 3

in this type of programming, callbacks are used in general

Answer 3

asynchronous

Question 4

represents a potential value or error that will be available at some time in the future

Answer 4

Future class

Question 5

provides a more linear and readable way to write asynchronous code

Answer 5

async/await

Question 6

reduces the need for nested call backs or .then() chains

Answer 6

async/await

Question 7

use cases to consider in implementing asynchronous programming (4)

Answer 7

1. reading data from a file asynchronously
2. receiving data from a network socket
3. listening to events from a sensor
4. handling a continuous flow of data

Question 8

a continuous sequence of asynchronous events

Answer 8

stream

Question 9

blocking operations while in progress, the program is unresponsive to other elements

Answer 9

synchronous

Question 10

non-blocking; uses callbacks, futures, and streams to notify the program when they’re finished

Answer 10

asynchronous

Question 11

importance of testing (3)

Answer 11

1. ensures app quality - features, UX
2. reduces bugs - errors
3. maintainability - incremental

Question 12

types of testing (3)

Answer 12

1. unit testing
2. widget testing
3. integration

Question 13

flutter package to use for testing

Answer 13

flutter_test

Question 14

what type of testing is being shown by the sample code

void main() {

  test('should double the number', () {

    // Arrange

    int input = 5;

    // Act

    int result = doubleNumber(input);

    // Assert

    expect(result, 10);

  });

  test('should handle zero', () {

    expect(doubleNumber(0), 0);

  });

  test('should handle negative numbers', () {

    expect(doubleNumber(-3), -6);

  });

}

Answer 14

unit testing

Question 15

a testing method where individual components of an application are tested to verify their correctness

Answer 15

unit testing

Question 16

what type of testing is being shown by the sample code

void main() {

  testWidgets('should display the greeting with the name', (WidgetTester tester) async {

    // Arrange

    String testName = 'Flutter User';

    // Act

    await tester.pumpWidget(MaterialApp( // Wrap the widget in a MaterialApp

      home: GreetingWidget(name: testName),

    ));

    // Assert

    expect(find.text('Hello, $testName!'), findsOneWidget);

  });

}

Answer 16

widget testing

Question 17

a testing method used to verify if individual widgets function as expected

Answer 17

widget testing

Question 18

a testing method that verifies how different modules or components of an application interact and communicate when combined

Answer 18

integration testing

Question 19

% of code executed when your tests are ran

Answer 19

code coverage

Question 20

what is a reasonable code coverage

Answer 20

75% to 90%

Question 21

flutter command to see code coverage

Answer 21

flutter test –coverage

Question 22

pros of unit testing (3)

Answer 22

1. small, fast, isolated
2. easy to write
3. early detection

Question 23

cons of unit testing (3)

Answer 23

1. limited to scope
2. need to setup
3. refactoring

Question 24

pros of widget testing (3)

Answer 24

1. tests ui
2. simulate user interaction
3. more comprehensive

Question 25

cons of widget testing (2)

Answer 25

1. limited scope 2. harder to write than unit testing

Question 26

pros of integration testing (3)

Answer 26

1. tests the whole app 2. simulates real world issues 3. highest confidence

Question 27

cons of integration testing (3)

Answer 27

1. slowest 2. harder to write 3. harder to debug