import unittest
import re
import nltk
from nltk import pos_tag
from nltk.tokenize import word_tokenize
from nltk.corpus import stopwords
from nltk.stem import WordNetLemmatizer
from nltk.corpus import wordnet as wn


# Helper functions
def _require_success(test_case, condition, failure_message):
    if not condition:
        test_case._testMethodName = failure_message
        test_case.fail()

def _check_success(test_case, condition, success_message, failure_message):
    if condition:
        test_case._testMethodName = success_message
    else:
        test_case._testMethodName = failure_message
        test_case.fail()

# Function that SHOULD NOT be modified
def get_wordnet_pos(treebank_tag):
    if treebank_tag.startswith('J'):
        return wn.ADJ
    elif treebank_tag.startswith('V'):
        return wn.VERB
    elif treebank_tag.startswith('R'):
        return wn.ADV
    else:
        return wn.NOUN

class TestUserCode(unittest.TestCase):
    # Test that everything is imported correctly
    def test_imports(self):
        import user_code
        _require_success(
            self, 
            hasattr(user_code, "word_tokenize"), 
            "`word_tokenize` is not declared"
        )
        _require_success(
            self,
            user_code.word_tokenize == word_tokenize,
            "`word_tokenize` is declared, but it's not `nltk.tokenize.word_tokenize`"
        )
        _require_success(
            self, 
            hasattr(user_code, "stopwords"), 
            "`stopwords` is not declared"
        )
        _require_success(
            self,
            user_code.stopwords == stopwords,
            "`stopwords` is declared, but it's not `nltk.corpus.stopwords`"
        )
        _require_success(
            self, 
            hasattr(user_code, "WordNetLemmatizer"), 
            "`WordNetLemmatizer` is not declared"
        )
        _require_success(
            self,
            user_code.WordNetLemmatizer == WordNetLemmatizer,
            "`WordNetLemmatizer` is declared, but it's not `nltk.stem.WordNetLemmatizer`"
        )
        _require_success(
            self, 
            hasattr(user_code, "pos_tag"), 
            "`pos_tag` is not declared"
        )
        _require_success(
            self,
            user_code.pos_tag == pos_tag,
            "`pos_tag` is declared, but it's not `nltk.pos_tag`"
        )
        _require_success(
            self, 
            hasattr(user_code, "wn"), 
            "`wn` is not declared"
        )
        _require_success(
            self,
            user_code.wn == wn,
            "`wn` is declared, but it's not `nltk.corpus.wordnet`"
        )
        _require_success(
            self,
            hasattr(user_code, "nltk"),
            "`nltk` is not declared"
        )
        _require_success(
            self,
            user_code.nltk == nltk,
            "`nltk` is declared, but it's not `nltk` library"
        )
        self._testMethodName = "imports are correct"

    # Test that required NLTK resources are downloaded
    def test_nltk_downloads(self):
        import user_code
        _require_success(
            self,
            hasattr(user_code, "nltk"),
            "`nltk` is not declared"
        )
        _require_success(
            self,
            user_code.nltk == nltk,
            "`nltk` is declared, but it's not `nltk` library"
        )
        with open("user_code.py", "r") as f:
            user_code_text = f.read()
            _require_success(
                self,
                re.search(r"nltk *\. *download *$ *'punkt_tab' *$", user_code_text),
                "Code for downloading `'punkt_tab'` shouldn't be modified"
            )
            _require_success(
                self,
                re.search(r"nltk *\. *download *$ *'stopwords' *$", user_code_text),
                "Code for downloading `'stopwords'` shouldn't be modified"
            )
            _require_success(
                self,
                re.search(r"nltk *\. *download *$ *'averaged_perceptron_tagger_eng' *$", user_code_text),
                "Code for downloading `'averaged_perceptron_tagger_eng'` shouldn't be modified"
            )
            _require_success(
                self,
                re.search(r"nltk *\. *download *$ *'wordnet' *$", user_code_text),
                "Code for downloading `'wordnet'` is not provided"
            )
        self._testMethodName = "NLTK resources are downloaded"

    # Test get_wordnet_pos
    def test_get_wordnet_pos(self):
        import user_code
        _require_success(
            self, 
            hasattr(user_code, "get_wordnet_pos"), 
            "`get_wordnet_pos` is not declared"
        )
        _require_success(
            self, 
            callable(user_code.get_wordnet_pos), 
            "`get_wordnet_pos` is not a function"
        )
        pos_tags = pos_tags = ['CC', 'CD', 'DT', 'EX', 'FW', 'IN', 'JJ', 'JJR', 'JJS', 'LS', 'MD', 'NN', 'NNS', 'NNP', 'NNPS', 'PDT', 'POS', 'PRP', 'PRP$', 'RB', 'RBR', 'RBS', 'RP', 'SYM', 'TO', 'UH', 'VB', 'VBD', 'VBG', 'VBN', 'VBP', 'VBZ', 'WDT', 'WP', 'WP$', 'WRB']
        _check_success(
            self, 
            list(map(user_code.get_wordnet_pos, pos_tags)) == list(map(get_wordnet_pos, pos_tags)),
            "`get_wordnet_pos` is correctly defined",
            "`get_wordnet_pos` shouldn't be modified"
        )
    
    # Test original text
    def test_text(self):
        import user_code
        expected = """Late in the evening, as the stars began to twinkle in the clear night sky, 
an old man sat quietly on the porch, reminiscing about his youthful adventures."""
        _require_success(
            self, 
            hasattr(user_code, "text"), 
            "`text` is not declared"
        )
        _check_success(
            self,
            user_code.text == expected,
            "`text` contains correct value",
            "`text` shouldn't be modified"
        )

    # Test lowercase conversion
    def test_text_lower(self):
        import user_code
        _require_success(
            self, 
            hasattr(user_code, "text"), 
            "`text` is not declared"
        )
        _require_success(
            self, 
            isinstance(user_code.text, str), 
            "`text` is not a string"
        )
        _require_success(
            self, 
            hasattr(user_code, "text_lower"), 
            "`text_lower` is not declared"
        )
        _check_success(
            self,
            user_code.text_lower == user_code.text.lower(),
            "`text_lower` is computed correctly",
            "`text_lower` is not the lowercase of `text`"
        )

    # Test tokenization of text_lower
    def test_tokens(self):
        import user_code
        _require_success(
            self, 
            hasattr(user_code, "text_lower"), 
            "`text_lower` is not declared"
        )
        _require_success(
            self, 
            isinstance(user_code.text_lower, str), 
            "`text_lower` is not a string"
        )
        _require_success(
            self, 
            hasattr(user_code, "tokens"), 
            "`tokens` is not declared"
        )
        _check_success(
            self,
            user_code.tokens == word_tokenize(user_code.text_lower),
            "`tokens` is computed correctly",
            "`text_lower` is not correctly tokenized into words"
        )

    # Test stop_words set
    def test_stop_words(self):
        import user_code
        _require_success(
            self, 
            hasattr(user_code, "stop_words"), 
            "`stop_words` is not declared"
        )
        _require_success(
            self, 
            isinstance(user_code.stop_words, set), 
            "`stop_words` is not a set"
        )
        _check_success(
            self,
            user_code.stop_words == set(stopwords.words('english')),
            "`stop_words` contains correct English stopwords set",
            "`stop_words` doesn't contain English stopwords"
        )

    # Test filtered_tokens filtering
    def test_filtered_tokens(self):
        import user_code
        _require_success(
            self, 
            hasattr(user_code, "tokens"), 
            "`tokens` is not declared"
        )
        _require_success(
            self, 
            isinstance(user_code.tokens, list), 
            "`tokens` is not a list"
        )
        _require_success(
            self, 
            hasattr(user_code, "stop_words"), 
            "`stop_words` is not declared"
        )
        _require_success(
            self, 
            isinstance(user_code.stop_words, set), 
            "`stop_words` is not a set"
        )
        _require_success(
            self, 
            hasattr(user_code, "filtered_tokens"), 
            "`filtered_tokens` is not declared"
        )
        expected = [tok for tok in user_code.tokens if tok not in user_code.stop_words]
        _check_success(
            self,
            user_code.filtered_tokens == expected,
            "`filtered_tokens` is computed correctly",
            "stopword in `tokens` are not correctly filtered out"
        )

    # Test tagged_tokens tagging
    def test_tagged_tokens(self):
        import user_code
        _require_success(
            self, 
            hasattr(user_code, "filtered_tokens"), 
            "`filtered_tokens` is not declared"
        )
        _require_success(
            self, 
            isinstance(user_code.filtered_tokens, list), 
            "`filtered_tokens` is not a list"
        )
        _require_success(
            self, 
            hasattr(user_code, "tagged_tokens"), 
            "`tagged_tokens` is not declared"
        )
        _check_success(
            self,
            user_code.tagged_tokens == pos_tag(user_code.filtered_tokens),
            "`tagged_tokens` is computed correctly",
            "`filtered_tokens` are not correctly pos tagged"
        )

    # Test lemmatizer instance
    def test_lemmatizer(self):
        import user_code
        _require_success(
            self, 
            hasattr(user_code, "lemmatizer"), 
            "`lemmatizer` is not declared"
        )
        _check_success(
            self,
            isinstance(user_code.lemmatizer, WordNetLemmatizer),
            "`lemmatizer` is defined correctly",
            "`lemmatizer` is not an instance of `WordNetLemmatizer`"
        )

    # Test lemmatizing results
    def test_lemmatized_tokens(self):
        import user_code
        _require_success(
            self, 
            hasattr(user_code, "lemmatizer"), 
            "`lemmatizer` is not declared"
        )
        _require_success(
            self,
            isinstance(user_code.lemmatizer, WordNetLemmatizer),
            "`lemmatizer` is not an instance of `WordNetLemmatizer`"
        )
        _require_success(
            self, 
            hasattr(user_code, "filtered_tokens"), 
            "`filtered_tokens` is not declared"
        )
        _require_success(
            self, 
            isinstance(user_code.filtered_tokens, list), 
            "`filtered_tokens` is not a list"
        )
        _require_success(
            self, 
            hasattr(user_code, "lemmatized_tokens"), 
            "`lemmatized_tokens` is not declared"
        )
        expected = [user_code.lemmatizer.lemmatize(tok, get_wordnet_pos(tag)) for tok, tag in user_code.tagged_tokens]
        _check_success(
            self,
            user_code.lemmatized_tokens == expected,
            "`lemmatized_tokens` is computed correctly",
            "`filtered_tokens` are not correctly lemmatized"
        )

    # Test print statement
    def test_print(self):
        with open("user_code.py", "r") as f:
            user_code_text = f.read()
        _check_success(
            self,
            re.search(r"print *$ *' ' *\. *join *\( *lemmatized_tokens *$", user_code_text),
            "print statement is correct",
            "print statement shouldn't be modified"
        )


if __name__ == '__main__':
    nltk.download('punkt_tab')
    nltk.download('stopwords')
    nltk.download('averaged_perceptron_tagger_eng')
    nltk.download('wordnet')
    unittest.main()

test_main.py

Explore the fundamentals of Natural Language Processing (NLP) by learning essential text preprocessing techniques and methods for representing text data. Gain practical experience with the tools used to clean, analyze, and interpret textual information. Develop the skills needed to transform raw language into structured insights, laying a strong foundation for advanced applications in artificial intelligence and machine learning.

Dive into the fundamentals of text preprocessing to prepare raw text for analysis. Learn how to tokenize text, filter out stop words, and customize tokenization with regular expressions.

Discover how words can be reduced to their base forms using stemming and lemmatization. Master part-of-speech tagging to enrich text with grammatical context and apply POS-aware lemmatization.

Learn how text can be represented with numbers using vector space models. Get hands-on experience by implementing and customizing two popular vector space models: bag of words and TF-IDF.

Gain a solid understanding of word embeddings and how they capture semantic meaning. Explore CBoW and Skip-gram architectures used in Word2Vec, and implement them on your own.

Challenge: Lemmatization with POS Tagging

Solution

Awesome!

Challenge: Lemmatization with POS Tagging

Solution