how-to-write-score-unit-test.md

title
How to write SCORE unit test

This document explains how to write SCORE unit-test using T-Bears unit-test framework.

Purpose

Understand how to write SCORE unit-test

Prerequisite

• SCORE Overview
• T-Bears Overview
• ICON Python SDK

How to Write SCORE Unit Test Code

SCORE unittest should inherit ScoreTestCase. The SCORE unit test code works as follows

• Get SCORE instance to be tested
• Call SCORE method
• Check the result

Functions Provided by ScoreTestCase

• Instantiate SCORE
  • Instantiate SCORE. So, you can access attributes and methods of SCORE like a general object.
• Set property in SCORE
  • Provide the ability to set properties used inside SCORE methods.
• Mock state DB
  • Store changed state caused by SCORE method invocation. The state is stored in memory, not in the file system.
• Mock event log
  • It is sufficient to check that the event log has been called
• Mock internalCall(call external function in SCORE).
  • The operation on the other SCORE is considered to be reliable. so, what you need is InternalCall called with specified arguments.

Methods

ScoreTestCase has 11 main methods. Inside setUp method and tearDown method, ScoreTestCase sets the environment for SCORE unit-test and clears them. So, if you want to override setUp or tearDown, you should call super() as a first statement in the overridden method.

Getting SCORE instance

• get_score_instance(score_class, owner, on_install_params)
  • Get an instance of the SCORE class passed as an score_class argument
  • parameters
    • score_class : SCORE to instantiate
    • owner : Address to set as owner of SCORE
    • on_install_params : parameters of on_install_method
  • Refer to setUp method in simple_score2/tests/test_unit_simple_score2.py
• update_score(prev_score_address, score_class, on_update_params)
  • Update SCORE at prev_score_address with score_class instance and get updated SCORE
  • parameters
    • Prev_score_address : address of SCORE to update
    • score_class : SCORE class to update
    • on_update_params : parameters of on_update method
  • Refer to test_update method in simple_score2/tests/test_unit_simple_score2.py

Setting SCORE properties

• set_msg(sender, value)
  • Set msg property in SCORE
  • parameters
    • sender : Set sender attribute of msg to given sender argument
    • value : Set value attribute of msg to given sender argument
  • Refer to test_msg method in simple_score2/tests/test_unit_simple_score2.py
• set_tx(origin, timestamp, _hash, index, nonce)
  • Set tx property in SCORE
  • parameters
    • origin : Set origin attribute of tx to given origin argument
    • timestamp : Set timestamp attribute of tx to given timestamp argument
    • _hash : Set hash attribute of tx to given _hash argument
    • index : Set index attribute of tx to given index argument
    • nonce : Set nonce attribute of tx to given nonce argument
  • Refer to test_tx method in simple_score2/tests/test_unit_simple_score2.py
• set_block(height, timestamp)
  • Set the block property inside SCORE. If you pass only height, the value of block.timestamp is set to height * 2 seconds. When this method is called, the block_height inside the SCORE associated with the block is set to height, and the return value of the now () method is set to timestamp. It should be called if you use the value associated with the block information in the SCORE method you are calling.
  • parameters
    • height : Set height attribute of block to given height argument
    • timestamp : Set timestamp attribute of block to given timestamp argument
  • Refer to test_block method in simple_score2/tests/test_unit_simple_score2.py

Patching InternalCall & asserting InternalCall

• register_interface_score(internal_score_address)
  • This method should be called before testing the internal_call that calls the SCORE method with an internal_score_address address. If you call this method, you can use the assert_internal_call method to evaluate whether internal_call is called properly with specified arguments.
  • parameters
    • internal_score_address : address of interface SCORE
  • Refer to test_internal2 method in simple_score2/tests/test_unit_simple_score2.py
• patch_internal_method(score_address, method, new_method)
  • You will use this method for patching query method to set return value. Since this function internally calls register_interface_score, you don't need to call register_interface_score when calling this function. The third argument, the new method, must be a function with the same number of arguments as the actual method.
  • parameters
    • internal_score_address : address of the SCORE having method to be called
    • method : method to be patched
    • new_method : method to patch
  • Refer to test_interanl method in simple_score2/tests/test_unit_simple_score2.py
• assert_internal_call(internal_score_address, method, *params)
  • assert that internal call(mock) was called with the specified arguments. Raises an AssertionError if the params passed in are different to the last call to the mock.
  • parameters
    • internal_score_address : address of internal call SCORE
    • method : method to check
    • params : params to check
  • Refer to test_internal method in simple_score2/tests/test_unit_simple_score2.py

Utils

• transfer(_from, to, amount)
  • Transfer icx to given 'to' address. If you pass a SCORE address to the to argument, this method calls the SCORE fallback method.
  • parameters
    • _from : address of sender
    • to : address of receiver
    • amount : amount to transfer
  • Refer to test_transfer method in simple_score2/tests/test_unit_simple_score2.py
• get_balance(address)
  • Query icx balance of given address.
  • parameters
    • address : address to query for icx balance
  • Refer to test_get_balance method in simple_score2/tests/test_unit_simple_score2.py
• initialize_accounts(accounts_info)
  • Initialize accounts using given dictionary info.
  • parameters
    • accounts_info : dictionary with address as key and balance as value
  • Refer to setUp method in simple_score2/tests/test_unit_simple_score2.py

Examples

In this example, we'll use two simple SCOREs only have getter and setter. (the first SCORE has getter and setter and another SCORE has internalCall, getter, and setter)

simple_score/simple_score.py

from iconservice import *

class SimpleScore(IconScoreBase):

    def __init__(self, db: IconScoreDatabase) -> None:
        super().__init__(db)
        self.value = VarDB("value", db, value_type=str)

    @eventlog
    def SetValue(self, value: str): pass

    def on_install(self) -> None:
        super().on_install()

    def on_update(self) -> None:
        """Set `value` attribute to `updated value`"""
        super().on_update()
        self.value.set("updated value")
    
    @external(readonly=True)
    def hello(self) -> str:
        return "Hello"

    @external
    def setValue(self, value: str):
        """Set `value` attribute to given `value` parameter"""
        self.value.set(value)

        self.SetValue(value)

    @external(readonly=True)
    def getValue(self) -> str:
        """Return value of `value` attribute"""
        return self.value.get()
        

simple_score2/simple_score2.py

from iconservice import *


class SimpleScoreInterface(InterfaceScore):
    @interface
    def setValue(self, value): pass

    @interface
    def getValue(self)->str: pass


class SimpleScore2(IconScoreBase):

    def __init__(self, db: IconScoreDatabase) -> None:
        super().__init__(db)
        self.value = VarDB("value1", db, value_type=str)
        self.score_address = VarDB("score_address", db, value_type=Address)

    @eventlog(indexed=0)
    def SetValue(self, value: str): pass

    @eventlog(indexed=1)
    def SetSCOREValue(self, value: str): pass

    def on_install(self, score_address: 'Address') -> None:
        super().on_install()
        self.score_address.set(score_address)

    def on_update(self, value: str) -> None:
        """"Set `value` attribute to given `value` parameter"""
        super().on_update()
        self.value.set(value)
    
    @external(readonly=True)
    def getValue(self) -> str:
        """Return value of `value` attribute"""
        return self.value.get()

    @external
    def setValue(self, value: str):
        """Set `value` attribute to given `value` parameter"""
        self.value.set(value)

        self.SetValue(value)

    @external
    def setSCOREValue(self, value: str):
        """Invoke `setValue` method of SCORE having `self.score_address` as the address"""
        score = self.create_interface_score(self.score_address.get(), SimpleScoreInterface)
        score.setValue(value)

        self.SetSCOREValue(value)

    @external(readonly=True)
    def getSCOREValue(self) ->str:
        """Call `getValue` method of SCORE having `self.score_address` as the address"""
        score = self.create_interface_score(self.score_address.get(), SimpleScoreInterface)

        return score.getValue()

    @external(readonly=True)
    def write_on_readonly(self) ->str:
        """Try set value on read-only method"""
        self.value.set('3')
        return 'd'
        
    def t_msg(self):
        """This method is for understanding the ScoreTestCase.set_msg method"""
        assert self.msg.sender == Address.from_string(f"hx{'1234'*10}")
        assert self.msg.value == 3
    
    def t_tx(self):
        """This method is for understanding the ScoreTestCase.set_tx method"""
        assert self.tx.origin == Address.from_string(f"hx{'1234'*10}")
    
    def t_block(self):
        """This method is for understanding the ScoreTestCase.set_block method"""
        assert self.block.height == 3
        assert self.block.timestamp == 30
        assert self.block_height ==3
        assert self.now() == 30

simple_score2/tests/test_unit_simple_score2.py

from iconservice import Address
from iconservice.base.exception import DatabaseException
from tbears.libs.scoretest.score_unit_test_base import ScoreTestCase
from simple_score2 import SimpleScore2

class TestSimple(ScoreTestCase):
    def setUp(self):
        super().setUp()
        self.mock_score_address = Address.from_string(f"cx{'1234'*10}")
        self.score2 = self.get_score_instance(SimpleScore2, self.test_account1,
                                              on_install_params={'score_address': self.mock_score_address})
                                              
        self.test_account3 = Address.from_string(f"hx{'12345'*8}")
        self.test_account4 = Address.from_string(f"hx{'1234'*10}")
        account_info = {
                        self.test_account3: 10 ** 21,
                        self.test_account4: 10 ** 21}
        self.initialize_accounts(account_info)

    def test_set_value(self):
        """Testing setValue method of SimpleScore2"""
        str_value = 'string_value'
        self.score2.setValue(str_value)
        # assert event log called with specified arguments
        self.score2.SetValue.assert_called_with(str_value)
        
        self.assertEqual(self.score2.getValue(), str_value)

    def test_get_value_and_set_value(self):
        """Testing getValue method of SimpleScore2"""
        # at first, value is empty string
        self.assertEqual(self.score2.getValue(), '')

        str_value = 'strValue'
        self.score2.setValue(str_value)

        self.assertEqual(self.score2.getValue(), str_value)

    # try writing value inside readonly method
    def test_write_on_readonly(self):
        """Testing write_on_readonly method of SimpleScore2"""
        self.assertRaises(DatabaseException, self.score2.write_on_readonly)

    # internal call(Calling other SCORE's method)
    def test_internal_call(self):
        """Testing getSCOREValue method and setSCOREValue method of SimpleScore2"""
        self.patch_internal_method(self.mock_score_address, 'getValue', lambda: 150) # Patch the getValue function of SCORE at self.mock_score_address address with a function that takes no argument and returns 150
        value = self.score2.getSCOREValue()
        self.assertEqual(value, 150)
        self.assert_internal_call(self.mock_score_address, 'getValue') # assert getValue in self.mock_score_address is called.
        
        self.score2.setSCOREValue('asdf')
        self.assert_internal_call(self.mock_score_address, 'setValue', 'asdf') # assert setValue in self.mock_score_address is called with 'asdf'

    def test_internal_call2(self):
        """Testing setSCOREValue method of SimpleScore2"""
        # To determine whether a method is called properly with specified arguments, calling register_interface_score method is enough
        self.register_interface_score(self.mock_score_address)
        self.score2.setSCOREValue('asdf')
        self.assert_internal_call(self.mock_score_address, 'setValue', 'asdf')
        
    def test_msg(self):
        """Testing t_msg method of SimpleScore2"""
        self.set_msg(Address.from_string(f"hx{'1234'*10}"), 3)
        self.score2.t_msg() # On the upper line, set the msg property to pass the assert statement so that no exception is raised.

        self.set_msg(Address.from_string(f"hx{'12'*20}"), 3)
        self.assertRaises(AssertionError, self.score2.t_msg) # On the upper line, set the msg property not to pass the assert statement, and raise an exception.

    def test_tx(self):
        """Testing t_tx method of SimpleScore2"""
        self.set_tx(Address.from_string(f"hx{'1234'*10}"))
        self.score2.t_tx() # On the upper line, set the tx property to pass the assert statement so that no exception is raised.

        self.set_tx(Address.from_string(f"hx{'12'*20}"))
        self.assertRaises(AssertionError, self.score2.t_tx) # On the upper line, set the tx property not to pass the assert statement, and raise an exception.

    def test_block(self):
        """Testing t_block method of SimpleScore2"""
        self.set_block(3, 30)
        self.score2.t_block() # On the upper line, set the block property to pass the assert statement so that no exception is raised.

        self.set_block(3)
        self.assertRaises(AssertionError, self.score2.t_block) # On the upper line, set the block property not to pass the assert statement, and raise an exception.
        
    def test_update(self):
        """Testing on_update method of SimpleScore2"""
        self.score2 = self.update_score(self.score2.address, SimpleScore2, on_update_params={"value": "updated_value"})
        self.assertEqual(self.score2.value.get(), "updated_value") # In the on_update method of SimpleScore2, set the value of the value to "updated_value".

    def test_get_balance(self):
        balance = self.get_balance(self.test_account3)
        self.assertEqual(balance, 10**21)

    def test_transfer(self):
        # before calling transfer method, check balance of test_account3 and test_account4
        amount = 10**21
        balance_3 = self.get_balance(self.test_account3)
        self.assertEqual(balance_3, amount)
        balance_4 = self.get_balance(self.test_account4)
        self.assertEqual(balance_4, amount)

        self.transfer(self.test_account3, self.test_account4, amount)
        # after calling transfer method, check balance of test_account3 and test_account4
        balance_3 = self.get_balance(self.test_account3)
        self.assertEqual(balance_3, 0)
        balance_4 = self.get_balance(self.test_account4)
        self.assertEqual(balance_4, amount*2)

Run test code

$ tbears test simple_score2
........
----------------------------------------------------------------------
Ran 11 tests in 0.027s

OK