Naive Substring Algorithm

naivesubstring.py

def indexOf(text, string):
    for i in range(len(text)):
        didBreak = False
        for j in range(len(string)):
            if (i+j >= len(text)):
                didBreak = True
                break
            if (text[i + j] != string[j]):
                didBreak = True
                break
        if (not didBreak): return i
    return -1
# should work if not in there at all
assert(indexOf("Interested in writing your own Python scenarios and demos?", "z") == -1)
# should work if substring bigger than string
assert(indexOf("z", "Interested in writing your own Python scenarios and demos?") == -1)
# should work normally
assert(indexOf("Interested in writing your own Python scenarios and demos?", "in") == 11)
# should work if it is the ending part of string or partially found
assert(indexOf("Interested in writing your own Python scenarios and demos?", "mos?.") == -1)