Coding Challenge: Wordcount

wordcount/README.md

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+# Learn by Doing: Build a Clone of the Unix `wc` Shell Command
+
+This folder contains supporting materials for the [wordcount coding challenge](https://realpython.com/courses/wordcount/) on Real Python.
+
+## How to Get Started?
+
+### Cloud Environment
+
+If you'd like to solve this challenge with a minimal setup required, then click the button below to launch a pre-configured environment in the cloud:
+
+[![Open in GitHub Codespaces](https://github.com/codespaces/badge.svg)](https://codespaces.new/realpython/materials?quickstart=1&devcontainer_path=.devcontainer%2Fwordcount%2Fdevcontainer.json)
+
+Alternatively, follow the steps below to set up the environment on your local machine.
+
+### Local Computer
+
+Use the [downloader tool](https://realpython.github.io/gh-download/?url=https%3A%2F%2Fgithub.com%2Frealpython%2Fmaterials%2Ftree%2Fmaster%2Fwordcount) to get the project files or clone the entire [`realpython/materials`](https://github.com/realpython/materials) repository from GitHub and change your directory to `materials/wordcount/`:
+
+```sh
+$ git clone https://github.com/realpython/materials.git
+$ cd materials/wordcount/
+```
+
+Create and activate a [virtual environment](https://realpython.com/python-virtual-environments-a-primer/), and then install the project in [editable mode](https://setuptools.pypa.io/en/latest/userguide/development_mode.html):
+
+```sh
+$ python -m venv venv/
+$ source venv/bin/activate
+(venv) $ python -m pip install -r requirements.txt -e .
+```
+
+Make sure to include the period at the end of the command!
+
+## How to Get Feedback?
+
+To display instructions for your current task:
+
+```sh
+(venv) $ pytest --task
+```
+
+To track your progress and reveal the acceptance criteria:
+
+```sh
+(venv) $ pytest
+```

wordcount/pyproject.toml

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+[build-system]
+requires = ["setuptools"]
+build-backend = "setuptools.build_meta"
+
+[project]
+name = "wordcount"
+version = "1.0.0"
+readme = "README.md"
+dependencies = [
+    "pytest",
+    "pytest-timeout",
+    "rich",
+]
+
+[project.scripts]
+wordcount = "wordcount:main"
+
+[tool.black]
+line-length = 79

wordcount/requirements.txt

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+iniconfig==2.0.0
+markdown-it-py==3.0.0
+mdurl==0.1.2
+packaging==24.1
+pluggy==1.5.0
+Pygments==2.18.0
+pytest==8.3.3
+pytest-timeout==2.3.1
+rich==13.9.2

wordcount/src/wordcount.py

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+# Uncomment the main() function below to solve your first task:
+# def main():
+#     pass

wordcount/tests/conftest.py

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+from fixtures import *
+
+pytest_plugins = ["realpython"]

wordcount/tests/fixtures.py

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+import random
+import string
+from dataclasses import dataclass
+from functools import cached_property
+from pathlib import Path
+from string import ascii_lowercase
+from subprocess import run
+from tempfile import TemporaryDirectory, gettempdir
+from typing import Callable
+
+import pytest
+
+
+@dataclass
+class FakeFile:
+    content: bytes
+    counts: tuple[int, ...]
+
+    @cached_property
+    def path(self) -> Path:
+        return Path("-")
+
+    def format_line(self, max_digits=None, selected=None):
+        if selected is None:
+            selected = 8 + 4 + 1
+        numbers = [
+            self.counts[i] for i in range(4) if selected & (2 ** (3 - i))
+        ]
+        if max_digits is None:
+            max_digits = len(str(max(numbers)))
+        counts = " ".join(
+            filter(None, [f"{number:{max_digits}}" for number in numbers])
+        )
+        if self.path.name == "-":
+            return f"{counts}\n".encode("utf-8")
+        else:
+            return f"{counts} {self.path}\n".encode("utf-8")
+
+
+@dataclass
+class TempFile(FakeFile):
+    @cached_property
+    def path(self) -> Path:
+        name = "".join(random.choices(ascii_lowercase, k=10))
+        return Path(gettempdir()) / name
+
+    def __post_init__(self):
+        self.path.write_bytes(self.content)
+
+    def delete(self):
+        if self.path.is_dir():
+            self.path.rmdir()
+        elif self.path.is_file():
+            self.path.unlink(missing_ok=True)
+
+
+@dataclass(frozen=True)
+class Files:
+    files: list[FakeFile]
+
+    def __iter__(self):
+        return iter(self.files)
+
+    def __len__(self):
+        return len(self.files)
+
+    @cached_property
+    def paths(self):
+        return [str(file.path) for file in self.files]
+
+    @cached_property
+    def expected(self):
+        if len(self.files) > 1:
+            return self.file_lines + self.total_line
+        else:
+            return self.file_lines
+
+    @cached_property
+    def file_lines(self):
+        return b"".join(file.format_line() for file in self.files)
+
+    @cached_property
+    def total_line(self):
+        totals = [sum(file.counts[i] for file in self.files) for i in range(4)]
+        md = len(str(max(totals)))
+        return f"{totals[0]:{md}} {totals[1]:{md}} {totals[3]:{md}} total\n".encode(
+            "utf-8"
+        )
+
+
+@pytest.fixture(scope="session")
+def small_file():
+    temp_file = TempFile(content=b"caffe\n", counts=(1, 1, 6, 6))
+    try:
+        yield temp_file
+    finally:
+        temp_file.delete()
+
+
+@pytest.fixture(scope="session")
+def big_file():
+    temp_file = TempFile(
+        content=(
+            b"Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod\n"
+            b"tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam,\n"
+            b"quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo\n"
+            b"consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse\n"
+            b"cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non\n"
+            b"proident, sunt in culpa qui officia deserunt mollit anim id est laborum.\n"
+        ),
+        counts=(6, 69, 447, 447),
+    )
+    try:
+        yield temp_file
+    finally:
+        temp_file.delete()
+
+
+@pytest.fixture(scope="session")
+def file1():
+    temp_file = TempFile(content=b"caffe latte\n", counts=(1, 2, 12, 12))
+    try:
+        yield temp_file
+    finally:
+        temp_file.delete()
+
+
+@pytest.fixture(scope="session")
+def file2():
+    temp_file = TempFile(
+        content=b"Lorem ipsum dolor sit amet\n", counts=(1, 5, 27, 27)
+    )
+    try:
+        yield temp_file
+    finally:
+        temp_file.delete()
+
+
+@pytest.fixture(scope="session")
+def unicode_file():
+    temp_file = TempFile(
+        content="Zażółć gęślą jaźń\n".encode("utf-8"), counts=(1, 3, 18, 27)
+    )
+    try:
+        yield temp_file
+    finally:
+        temp_file.delete()
+
+
+@pytest.fixture(scope="session")
+def small_files():
+    temp_files = [
+        TempFile(content=b"Mocha", counts=(0, 1, 5, 5)),
+        TempFile(content=b"Espresso\n", counts=(1, 1, 9, 9)),
+        TempFile(content=b"Cappuccino\n", counts=(1, 1, 11, 11)),
+        TempFile(content=b"Frappuccino", counts=(0, 1, 11, 11)),
+        TempFile(content=b"Flat White\n", counts=(1, 2, 11, 11)),
+        TempFile(content=b"Turkish Coffee", counts=(0, 2, 14, 14)),
+        TempFile(content=b"Irish Coffee Drink\n", counts=(1, 3, 19, 19)),
+        TempFile(content=b"Espresso con Panna", counts=(0, 3, 18, 18)),
+    ]
+    try:
+        yield Files(temp_files)
+    finally:
+        for file in temp_files:
+            file.delete()
+
+
+@pytest.fixture(scope="session")
+def medium_files(file1, file2, unicode_file):
+    return Files([file1, file2, unicode_file])
+
+
+@pytest.fixture(scope="session")
+def wc():
+    def function(*args, stdin: bytes | None = None) -> bytes:
+        process = run(["wordcount", *args], capture_output=True, input=stdin)
+        return process.stdout
+
+    return function
+
+
+@pytest.fixture(scope="session")
+def fake_dir():
+    with TemporaryDirectory(delete=False) as directory:
+        path = Path(directory)
+        try:
+            yield path
+        finally:
+            path.rmdir()
+
+
+@pytest.fixture(scope="function")
+def random_name():
+    return make_random_name()
+
+
+def make_random_name(length=10):
+    return "".join(random.choices(string.ascii_lowercase, k=length))
+
+
+@pytest.fixture(scope="session")
+def runner(wc, small_file, unicode_file, big_file, fake_dir):
+    return Runner(
+        wc, small_file, unicode_file, big_file, fake_dir, make_random_name()
+    )
+
+
+@dataclass
+class Runner:
+    wc: Callable
+    file1: FakeFile
+    file2: FakeFile
+    file3: FakeFile
+    fake_dir: Path
+    random_name: str
+
+    def __call__(self, *flags):
+        return self.wc(
+            *flags,
+            str(self.file1.path),
+            "-",
+            str(self.file2.path),
+            self.fake_dir,
+            "-",
+            str(self.file3.path),
+            self.random_name,
+            stdin=b"flat white",
+        )