Add Base64 encode and decode commands

fixit/base64utils.py

@@ -0,0 +1,20 @@
+"""Base64 text encoding and decoding utilities."""
+
+import base64
+import binascii
+
+
+def encode_text(text: str) -> str:
+    """Encode UTF-8 text as a Base64 string."""
+    encoded = base64.b64encode(text.encode("utf-8"))
+    return encoded.decode("ascii")
+
+
+def decode_text(text: str) -> str:
+    """Decode a Base64 string into UTF-8 text."""
+    try:
+        encoded = text.encode("ascii")
+        decoded = base64.b64decode(encoded, validate=True)
+        return decoded.decode("utf-8")
+    except (binascii.Error, UnicodeEncodeError, UnicodeDecodeError) as exc:
+        raise ValueError("Invalid Base64 input.") from exc

fixit/cli.py

@@ -1,10 +1,20 @@
+
 """Command line entry point: `fixit <command>`."""
 import argparse
 import sys
 import uuid
 from pathlib import Path
 
-from fixit import __version__, convert, jsonfmt, password, textutils, wordcount
+from fixit import (
+    __version__,
+    base64utils,
+    convert,
+    jsonfmt,
+    password,
+    textutils,
+    wordcount,
+)
+
 
 CONVERSIONS = {
     "c2f": convert.celsius_to_fahrenheit,
@@ -81,6 +91,7 @@ def run_slugify(args):
     "json": run_json,
     "palindrome": run_palindrome,
     "reverse": run_reverse,
+    "base64": run_base64,
     "slugify": run_slugify,
     "top-words": run_top_words,
 }
@@ -94,8 +105,15 @@ def build_parser() -> argparse.ArgumentParser:
         args = parser.parse_args(["wc", "hello world"])
         assert args.command == "wc"
     """
-    parser = argparse.ArgumentParser(prog="fixit", description="A tiny toolbox to practice open source.")
-    parser.add_argument("--version", action="version", version=f"fixit {__version__}")
+    parser = argparse.ArgumentParser(
+        prog="fixit",
+        description="A tiny toolbox to practice open source.",
+    )
+    parser.add_argument(
+        "--version",
+        action="version",
+        version=f"fixit {__version__}",
+    )
     sub = parser.add_subparsers(dest="command", required=True)
 
     wc = sub.add_parser("wc", help="count words, lines and characters")
@@ -122,7 +140,28 @@ def build_parser() -> argparse.ArgumentParser:
     rw = sub.add_parser("reverse", help="reverse the words in a sentence")
     rw.add_argument("text")
 
-    sg = sub.add_parser("slugify", help="convert text into a URL-friendly slug")
+    b64 = sub.add_parser("base64", help="encode or decode Base64 text")
+    b64_sub = b64.add_subparsers(
+        dest="base64_action",
+        required=True,
+    )
+
+    b64_encode = b64_sub.add_parser(
+        "encode",
+        help="encode text as Base64",
+    )
+    b64_encode.add_argument("text")
+
+    b64_decode = b64_sub.add_parser(
+        "decode",
+        help="decode Base64 text",
+    )
+    b64_decode.add_argument("text")
+
+    sg = sub.add_parser(
+        "slugify",
+        help="convert text into a URL-friendly slug",
+    )
     sg.add_argument("text")
 
     top = sub.add_parser("top-words", help="show the most frequent words")

tests/test_base64.py

@@ -0,0 +1,43 @@
+import pytest
+
+from fixit import base64utils, cli
+
+
+def test_encode_text():
+    assert base64utils.encode_text("hello") == "aGVsbG8="
+
+
+def test_decode_text():
+    assert base64utils.decode_text("aGVsbG8=") == "hello"
+
+
+def test_encode_unicode_text():
+    text = "\u0928\u092e\u0938\u094d\u0924\u0947"
+    assert base64utils.decode_text(base64utils.encode_text(text)) == text
+
+
+def test_empty_text():
+    assert base64utils.encode_text("") == ""
+    assert base64utils.decode_text("") == ""
+
+
+@pytest.mark.parametrize("value", ["%%%", "aGVsbG8", "////"])
+def test_invalid_base64_or_non_utf8_text(value):
+    with pytest.raises(ValueError, match="Invalid Base64 input"):
+        base64utils.decode_text(value)
+
+
+def test_cli_encode(capsys):
+    assert cli.main(["base64", "encode", "hello"]) == 0
+    assert capsys.readouterr().out == "aGVsbG8=\n"
+
+
+def test_cli_decode(capsys):
+    assert cli.main(["base64", "decode", "aGVsbG8="]) == 0
+    assert capsys.readouterr().out == "hello\n"
+
+
+def test_cli_invalid_base64(capsys):
+    assert cli.main(["base64", "decode", "%%%"]) == 1
+    captured = capsys.readouterr()
+    assert "Invalid Base64 input" in captured.err