Outline

• •Rules
  • •Details on rule
• •Tips for ut

Rules

• •AMAA pattern
• •Easy test case(suite) name for domain expert
• •Minimal mock usage
• •Increase refactoring resistance
• •Minimal test code
• •Fast

AMAA Pattern

Arrange, Mock(if exists), Act, Assert Pattern

EX)

func Test_BuyItemAndReduceInventory(t *testing.T) {
  // Arrange
  store := Store{}
  store.SetItems("Shampoo", 10)

  // Mock
  // ...mocking stripe

  // Act
  inventory := store.Buy("Shampoo", 6, 100)

  // Assert
  assert.Equal(inventory, 4)
}

Easy test case(suite) name for domain expert

Anti Pattern

• •

  Name the parts to be tested, such as function names and class names. EX) TestEther_GetBlockNumber

• •

  Mention detailed logic in a white box manner EX) it should call eth_blockNumber and return result

Best Practice

• •Name based on behavior EX) Test_GetBlockNumberForBlockChain EX) it returns blocknumber of blockchain node

Minimal mock usage

Anti Pattern

• •

  Write detailed logic mocks EX) if impl as below,

  go

  func (s *Some) DoSomething() {
    return helper.DoSomething()
  }
  

  in test

  go

  func Test_DoSomething(t *tesiting.T) {
    helper.mock(func(){
      return "hello"
    })
  
    s := Some{}
    result := s.DoSomething()
    assert.Equal(t, result, "hello")
  }
  

BestPractice

• •

  Testing detailed logic EX)

  go

  func Test_DoSomething(t *tesiting.T) {
    // Don't mock detail logic
  
    s := Some{}
    result := s.DoSomething()
    assert.Equal(t, result, "hello") // assert of detail logic
  }
  

• •

  Mock external service behavior EX)

  go

  func Test_getBalanceOfProvidedAccount(t *testing.T) {
    // mock block chain rpc node
    mock := alchemymock.NewAlchemyHttpMock(setting, t)
  defer mock.DeactivateAndReset()
    mock.RegisterResponder("eth_getBalance", `{"jsonrpc":"2.0","id":1,"result":"0x1234"}`)
  
    balance, err := alchemy.Core.GetBalance("0x", "latest")
  if err != nil {
  	t.Fatal(err)
  }
  assert.Equal(t, "4660", balance.String())
  }
  

Increase refactoring resistance

Anti Pattern

• •

  assert in mocking function call EX)

  go

  func Test_1(...) {
    // Mock
    // ... mock `func1`
  
    // Act
    result := Do()
  
    // Assert
    assert.Equal(t, func1.CalledTimes(), 1)
  }
  

Minimal test code

• •write trivial tests
  go

  func Add(a, b int) int {
    return a + b
  }
  

  in test
  go

  func Test_SomeOfTwoNumber(...) {
    assert(t, Add(1,2), 3) // It's OK
    assert(t, Add(-1, 2), 1) // trivial bc I don't think there is a high possibility of failure just by calling a standard function.
  }
  

Best Practice

• •

  use test helper

  go

  func newItemsForTest() []Item {
    return []Item{
      {Name: "Shampoo", Num: 1},
      {Name: "Pen", Num: 2},
    }
  }
  
  func Test_1(...) {
    // Arrange
    items := newItemsForTest()
  }
  
  func Test_2(...) {
    // Arrange
    items := newItemsForTest()
  }
  

Tips

• •Alchemy Mock: read `docs/docs/development/Mock.md``