Add pytest coverage for CLI and rendering behavior

tests/conftest.py

@@ -0,0 +1,57 @@
+"""Shared test fixtures for rp."""
+
+from __future__ import annotations
+
+from collections.abc import Callable, Iterator
+import io
+import json
+from pathlib import Path
+
+import pytest
+from rich.console import Console
+
+from rp.render import RenderOptions
+
+
+@pytest.fixture
+def tmp_file(tmp_path: Path) -> Callable[..., Path]:
+    """Factory fixture to create a temporary file with given content and suffix."""
+
+    def _make(content: str, suffix: str = ".txt", name: str | None = None) -> Path:
+        filename = name or f"test{suffix}"
+        p = tmp_path / filename
+        p.write_text(content, encoding="utf-8")
+        return p
+
+    return _make
+
+
+@pytest.fixture
+def capture_console() -> Iterator[Console]:
+    """A Rich Console that captures output instead of printing to stdout."""
+    console = Console(file=io.StringIO(), width=120, force_terminal=True)
+    yield console
+
+
+@pytest.fixture
+def default_options() -> RenderOptions:
+    """Default RenderOptions for testing."""
+    return RenderOptions()
+
+
+@pytest.fixture
+def sample_json() -> str:
+    """Valid JSON string for testing."""
+    return json.dumps({"name": "test", "value": 42, "items": [1, 2, 3]}, indent=2)
+
+
+@pytest.fixture
+def sample_markdown() -> str:
+    """Markdown content for testing."""
+    return "# Hello\n\nThis is **bold** and *italic*.\n\n- item 1\n- item 2\n"
+
+
+@pytest.fixture
+def sample_python() -> str:
+    """Python code for testing."""
+    return 'def hello(name: str = "world") -> str:\n    return f"Hello, {name}!"\n'