How do I tell whether a function has been called in Python?

Question

I'm writing unit tests for the first time and am having trouble wrapping my head around this. I have a method IsInitialized() that should return false if another method, LoadTable(), has never been called for the object. How do I Write a test method to verify this?

Answer 1

I would make it an attribute for simplicity:

class with_called_attribute:
    def __init__(self, func):
        self.func = func
        self.called = False

    def __call__(self, *args, **kwargs):
        self.called = True
        self.func(*args, **kwargs)

@with_called_attribute
def run_some_thing(*args, **kwargs):
    print("You called with:", *args, **kwargs)

run_some_thing.called
#>>> False

run_some_thing(10)
#>>> You called with: 10

run_some_thing.called
#>>> True

Answer 2

You can use a global variable and set it to True inside the function you want to check:

global hasRun
hasRun = False
def foo():
    global hasRun
    hasRun = True

def goop():
    global hasRun
    if hasRun == False:
        #Do something if it hasn't run

In your code:

global hasRun
hasRun = False

def LoadTable():
    global hasRun
    doStuff()
    hasRun = True

def IsInitialized():
    global hasRun
    return hasRun #Returns False if hasRun = False, and vice-versa

Answer 3

You need to check for object equality and use a flag to indicate the result.

eg

class Detector(object):
    __init__(self):
        self.loadTableIsCalledForObjA = False

detector = Detector() 

def isInitialized():
    if detector.loadTableIsCalledForObjA:
        return False

def loadTable(someObj):
    if type(someObj) is ObjA:
        detector.loadTableIsCalledForObjA = True