mcpbeat

Generating CLI Tests

https-deeplearning-ai/generating-cli-tests

Generate pytest tests for Typer CLI commands. Includes fixtures (temp_storage, sample_data), CliRunner patterns, confirmation handling (y/n/--force), and edge case coverage. Use when user asks to "write tests for", "test my CLI", "add test coverage", or any CLI + test request.

1k tokens
context cost
the whole folder, loaded on every use
1
files
instructions only
0
copies elsewhere
how many repositories repackaged it
1335
stars on the repo
on the repository, not the skill itself

Install

one command, takes just this skill from the repository
npx skills add https://github.com/https-deeplearning-ai/sc-agent-skills-files --skill generating-cli-tests

The instruction itself

13 sections, as written by the author

Generating CLI Tests

Patterns for generating tests for Typer CLI commands.

Workflow

  • Identify command type (Create/Read/Update/Delete/Bulk)
  • Ensure fixtures exist in conftest.py
  • Write tests using scenarios below
  • Run tests to verify

Fixtures (conftest.py)

import json
import pytest
from typer.testing import CliRunner


@pytest.fixture
def runner():
    """CLI test runner."""
    return CliRunner()


@pytest.fixture
def temp_storage(tmp_path, monkeypatch):
    """Empty storage for testing."""
    storage_dir = tmp_path / ".task"
    storage_dir.mkdir()
    storage_file = storage_dir / "tasks.json"
    storage_file.write_text(json.dumps({"version": 1, "tasks": []}))
    monkeypatch.setenv("TASK_STORAGE_PATH", str(storage_file))
    return storage_file


@pytest.fixture
def sample_data(temp_storage):
    """Pre-populated storage."""
    data = {
        "version": 1,
        "tasks": [
            {"title": "First task", "done": False, "priority": "low", "created_at": "2025-01-01T10:00:00", "due_date": None},
            {"title": "Second task", "done": True, "priority": "high", "created_at": "2025-01-01T11:00:00", "due_date": None},
        ]
    }
    temp_storage.write_text(json.dumps(data))
    return data

Test Structure (AAA)

def test_<command>_<scenario>(runner, temp_storage):
    # Arrange - via fixtures

    # Act
    result = runner.invoke(app, ["<command>", "<args>"])

    # Assert
    assert result.exit_code == 0
    assert "<expected>" in result.output

CliRunner Usage

from typer.testing import CliRunner
from task.main import app

runner = CliRunner()

# Basic
result = runner.invoke(app, ["add", "New task"])

# With options
result = runner.invoke(app, ["add", "Task", "--priority", "high"])

# With confirmation
result = runner.invoke(app, ["clear", "1"], input="y\n")  # Accept
result = runner.invoke(app, ["clear", "1"], input="n\n")  # Decline

# Skip confirmation
result = runner.invoke(app, ["clear", "1", "--force"])

Test Scenarios by Command Type

Create/Add

class TestAdd:
    def test_adds_task(self, runner, temp_storage):
        result = runner.invoke(app, ["add", "New task"])
        assert result.exit_code == 0
        assert "Added" in result.output

    def test_with_priority(self, runner, temp_storage):
        result = runner.invoke(app, ["add", "Task", "--priority", "high"])
        assert result.exit_code == 0

    def test_empty_title_shows_error(self, runner, temp_storage):
        result = runner.invoke(app, ["add", ""])
        assert result.exit_code == 2

Read/List

class TestList:
    def test_shows_tasks(self, runner, sample_data):
        result = runner.invoke(app, ["list"])
        assert result.exit_code == 0
        assert "First task" in result.output

    def test_empty_state(self, runner, temp_storage):
        result = runner.invoke(app, ["list"])
        assert "No tasks" in result.output or "empty" in result.output.lower()

    def test_with_filter(self, runner, sample_data):
        result = runner.invoke(app, ["list", "--done"])
        assert result.exit_code == 0

Update/Done

class TestDone:
    def test_marks_done(self, runner, sample_data):
        result = runner.invoke(app, ["done", "1"])
        assert result.exit_code == 0

    def test_not_found(self, runner, temp_storage):
        result = runner.invoke(app, ["done", "999"])
        assert result.exit_code == 1
        assert "not found" in result.output.lower()

Delete/Clear

class TestClear:
    def test_confirmed(self, runner, sample_data):
        result = runner.invoke(app, ["clear", "1"], input="y\n")
        assert result.exit_code == 0
        assert "Deleted" in result.output

    def test_declined(self, runner, sample_data):
        result = runner.invoke(app, ["clear", "1"], input="n\n")
        assert "Cancelled" in result.output

    def test_force(self, runner, sample_data):
        result = runner.invoke(app, ["clear", "1", "--force"])
        assert result.exit_code == 0

    def test_not_found(self, runner, temp_storage):
        result = runner.invoke(app, ["clear", "999", "--force"])
        assert result.exit_code == 1

Edge Cases to Cover

| Category | Test Cases |

|----------|------------|

| Invalid Input | Empty string, wrong type, out of range |

| Not Found | ID doesn't exist |

| Boundary | Zero, negative, first/last item |

| State | Already done, empty storage |

| Confirmation | Accept (y), decline (n), force flag |

Checklist

  • [ ] Test file: tests/test_<command>.py
  • [ ] Fixtures in conftest.py
  • [ ] Uses CliRunner from typer.testing
  • [ ] AAA structure (Arrange, Act, Assert)
  • [ ] Tests exit codes: 0, 1, 2
  • [ ] Destructive commands: tests y/n and --force
  • [ ] Output assertions check expected messages

Running Tests

uv run pytest                       # All tests
uv run pytest -v                    # Verbose
uv run pytest tests/test_add.py    # Specific file

How to use it

Copy the folder

Take https-deeplearning-ai/generating-cli-tests from the repository into ~/.claude/skills for personal use, or into .claude/skills inside a project.

Check the name does not clash

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