init

.gitignore

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+.git
+.venv
+.pytest_cache
+.Python
+*.tgz
+*/__pycache__
+*/*.egg-info

makefile

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+SHELL := /bin/bash
+MIN_PYTHON_VERSION = 3.11.0
+INSTALLED_PYTHON := $(shell python -V | grep -Po '(?<=Python)(.+)')
+MIN_VERSION_MET := $(shell if awk "BEGIN {exit !($(INSTALLED_PYTHON) >= $(MIN_PYTHON_VERSION))}"; then echo true; else echo false; fi)
+LOCAL_PYTHON_PATH = .Python/bin/python$(shell echo $(MIN_PYTHON_VERSION)|grep  -Po '[0-9]{1,2}.[0-9]{1,2}')
+MINIMUM_COVERAGE = 80
+WD = $(shell pwd)
+
+define venv_run
+	source .venv/bin/activate && $1
+endef
+
+all: init standards test
+
+create-environment:
+ifeq ($(MIN_VERSION_MET), true)
+	python -m venv .venv
+else
+ifeq (,$(wildcard $(LOCAL_PYTHON_PATH)))
+	mkdir -p .Python
+	wget https://www.python.org/ftp/python/$(MIN_PYTHON_VERSION)/Python-$(MIN_PYTHON_VERSION).tgz -O Python-$(MIN_PYTHON_VERSION).tgz
+	tar -xvzf Python-$(MIN_PYTHON_VERSION).tgz
+	cd Python-$(MIN_PYTHON_VERSION) && ./configure --prefix $(WD)/.Python && make && make install
+	rm Python-$(MIN_PYTHON_VERSION).tgz
+	rm -R Python-$(MIN_PYTHON_VERSION)
+endif
+	$(LOCAL_PYTHON_PATH) -m venv .venv
+endif
+
+install-dev:
+	$(call venv_run, pip install --upgrade pip)
+	$(call venv_run, pip install .[dev])
+	$(call venv_run, pip install -e .)
+install:
+	$(call venv_run, pip install --upgrade pip)
+	$(call venv_run, pip install .)
+
+dev-init: create-environment install-dev
+init: create-environment install
+
+# testing / standards
+pytest:
+	$(call venv_run, pytest -v)
+safety:
+	$(call venv_run, safety check)
+bandit:
+	$(call venv_run, bandit -r src/)
+flake:
+	$(call venv_run, flake8 src/)
+coverage:
+	$(call venv_run, coverage run --omit .venv -m pytest && coverage report -m --fail-under=$(MINIMUM_COVERAGE))
+autopep8:
+	$(call venv_run, autopep8  --in-place --recursive src/*)
+pkg_size:
+	test/package_size.sh
+test: pytest coverage pkg_size
+standards: autopep8 bandit flake safety
+
+clean:
+	rm -Rf build dist .pytest_cache .coverage src/droppii/__pycache__ test/__pycache__

pyproject.toml

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+[project]
+name = "uk_plate_reader"
+version = "0.0.0"
+description = ""
+readme = ""
+requires-python = ">=3.11"
+dependencies = []
+classifiers = [
+    "Programming Language :: Python :: 3",
+    "License :: OSI Approved :: Apache Software License",
+    "Operating System :: Unix",
+]
+
+[project.optional-dependencies]
+dev = ["pytest"]
+
+[build-system]
+requires = ["setuptools>=65.0"]
+build-backend = "setuptools.build_meta"

src/uk_plate_reader.py

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+import json
+import sys
+
+with open("./data/area_codes.json", "r") as f:
+    areas = json.load(f)
+
+def get_legacy_year(plate:str):
+    base_year = 1983
+    try:
+        year_indicator = plate[0]
+    except IndexError:
+        return False
+    year_offset = ord(year_indicator.upper()) - ord("A")
+    year = base_year + year_offset
+    if year < 1983 or year >= 2001:
+        year = False
+    return year
+
+def get_year(plate:str)->int:
+    year_indicator = int(plate[2:4])
+    if year_indicator >= 50:
+        year_indicator = year_indicator - 50
+    return year_indicator + 2000
+
+def get_legacy_area(plate:str):
+    if len(plate.replace(" ","")) == 5:
+        area_code = plate[-1]
+    elif len(plate.replace(" ", "")) == 6:
+        area_code = plate[-2:]
+    return areas.get("legacy_style").get(area_code)
+
+def get_area(plate:str):
+    area_code = plate[0:2]
+    area, _ = areas.get("modern_style").get(area_code)
+    return area
+
+def is_legacy(plate):
+    try:
+        return int(plate[1])
+    except ValueError:
+        return False
+
+def read_licence_plate(plate:str):
+    if is_legacy(plate):
+        area = get_legacy_area(plate)
+        year = get_legacy_year(plate)
+    else:
+        area = get_area(plate)
+        year = get_year(plate)
+    if not area or not year:
+        raise Exception("Not a valid licence plate")
+    return [area, year]
+
+if __name__ == "__main__":
+    if len(sys.argv) > 1:
+        print(read_licence_plate(sys.argv[1]))

test/test_main.py

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+from uk_plate_reader import read_licence_plate
+import pytest # type: ignore
+
+def test_old_plate_returns_correct_area():
+    assert read_licence_plate("N12 ANA")[0] == "Manchester"
+    assert read_licence_plate("L12 AOE")[0] == "Birmingham"
+    assert read_licence_plate("L12 AP")[0] == "Surrey"
+
+def test_new_plate_returns_correct_area():
+    assert read_licence_plate("LL07 XYZ")[0] == "London"
+    assert read_licence_plate("OJ57 XYZ")[0] == "Oxford"
+    assert read_licence_plate("BB62 XYZ")[0] == "Birmingham"
+
+def test_old_plate_returns_correct_year():
+    assert read_licence_plate("N12 AOE")[1] in [1995, 1996]
+    assert read_licence_plate("L12 AOE")[1] in [1993, 1994]
+
+def test_new_plate_returns_correct_year():
+    assert read_licence_plate("AB07 XYZ")[1] == 2007
+    assert read_licence_plate("AB57 XYZ")[1] in [2007, 2008]
+    assert read_licence_plate("AB62 XYZ")[1] in [2012, 2013]
+
+def test_invalid_plate_returns_error():
+    for plate in ["A", "ZZ07 LMA", "Z12 ANA", "Y12 ZZZ"]:
+        with pytest.raises(Exception):
+            read_licence_plate(plate)
+
+def test_empty_input_returns_error():
+    with pytest.raises(IndexError):
+        read_licence_plate("")
+
+def test_legacy_single_char_area():
+    assert read_licence_plate("N12 AM")[0] == "Cheshire"