jest-test-practicing

Task 1

• Write a function stringLength(string) that takes any string as an argument and returns its characters count.
• Now write a test for this function.
• Next, expand your function to make it check if the string is at least 1 character long and not longer than 10 characters.
• Throw errors if those conditions are not met.
• Add tests for the new functionality.

Task 2

• Write a function reverseString(string) function.
• It should take a string as an argument and return it reversed.
• Write at least one test for this function.

Task 3

In this task, you will need to write several tests for each tested function.

• You could write all of your tests directly at the top level, but it's better to group related tests so their output is more readable.

• Jest has the describe() method just for that.

• Read about it here and apply it in your tests for this task:

• Write a simple calculator class or object, which will have 4 methods:

• add, subtract, divide, and multiply.

• Write at least 3 tests for each of the calculator methods.

• Group tests for each method using describe() method.

Task 4

In this task we're going to do things differently:

• Start by writing a test for a capitalize(string) function.
• Your test should make sure that this function takes a string as an argument and returns that string with the first character capitalized.
• Run your test - it should fail because you don’t have the capitalize(string) function implemented yet.
• Now make your tests green by implementing the capitalize(string) function.
• Think about what the minimum amount of code is necessary to pass this test and write it.