Add pytest coverage for CLI and rendering behavior

tests/test_detect.py

@@ -0,0 +1,142 @@
+"""Tests for file type detection."""
+
+from __future__ import annotations
+
+from pathlib import Path
+
+import pytest
+
+from rp.detect import EXTENSION_MAP, _FILENAME_MAP, detect_type
+
+
+class TestExplicitType:
+    """Priority 1: explicit_type always wins."""
+
+    def test_explicit_overrides_everything(self) -> None:
+        assert detect_type(path="foo.py", content="...", explicit_type="json") == "json"
+
+    def test_explicit_with_none_path_and_content(self) -> None:
+        assert detect_type(explicit_type="rust") == "rust"
+
+    def test_explicit_empty_string(self) -> None:
+        # Empty string is falsy but not None, so it should still win.
+        assert detect_type(explicit_type="") == ""
+
+
+class TestFilenameMap:
+    """Priority 2: special filenames like Dockerfile."""
+
+    def test_dockerfile(self) -> None:
+        assert detect_type(path="Dockerfile") == "docker"
+
+    def test_dockerfile_with_path(self) -> None:
+        assert detect_type(path="/some/dir/Dockerfile") == "docker"
+
+    def test_makefile(self) -> None:
+        assert detect_type(path="Makefile") == "make"
+
+    def test_makefile_with_path(self) -> None:
+        assert detect_type(path="src/Makefile") == "make"
+
+
+class TestExtensionMap:
+    """Priority 3: file extension lookup."""
+
+    def test_python(self) -> None:
+        assert detect_type(path="script.py") == "python"
+
+    def test_python_case_insensitive(self) -> None:
+        assert detect_type(path="SCRIPT.PY") == "python"
+
+    def test_json_extension(self) -> None:
+        assert detect_type(path="data.json") == "json"
+
+    def test_markdown(self) -> None:
+        assert detect_type(path="README.md") == "markdown"
+
+    def test_rust(self) -> None:
+        assert detect_type(path="main.rs") == "rust"
+
+    def test_go(self) -> None:
+        assert detect_type(path="main.go") == "go"
+
+    def test_unknown_extension(self) -> None:
+        assert detect_type(path="file.xyz") == "text"
+
+    def test_no_extension(self) -> None:
+        assert detect_type(path="Makefile") == "make"
+
+    def test_double_extension(self) -> None:
+        assert detect_type(path="archive.tar.gz") == "text"
+
+    def test_hidden_file(self) -> None:
+        assert detect_type(path=".bashrc") == "text"
+
+    @pytest.mark.parametrize(
+        ("suffix", "expected"),
+        sorted(EXTENSION_MAP.items()),
+    )
+    def test_all_known_extensions_detect(self, suffix: str, expected: str) -> None:
+        assert detect_type(path=f"example{suffix}") == expected
+
+
+class TestContentJsonDetection:
+    """Priority 4: detect JSON from content when path gives no clue."""
+
+    def test_json_object(self, sample_json: str) -> None:
+        assert detect_type(content=sample_json) == "json"
+
+    def test_json_array(self) -> None:
+        assert detect_type(content="[1, 2, 3]") == "json"
+
+    def test_json_with_whitespace(self) -> None:
+        assert detect_type(content='  \n  {"a": 1}  \n  ') == "json"
+
+    def test_invalid_json_braces(self) -> None:
+        assert detect_type(content="{invalid json}") == "text"
+
+    def test_non_json_content(self) -> None:
+        assert detect_type(content="hello world") == "text"
+
+    def test_empty_content(self) -> None:
+        assert detect_type(content="") == "text"
+
+    def test_content_with_valid_path_takes_priority(self) -> None:
+        assert detect_type(path="script.py", content='{"a": 1}') == "python"
+
+
+class TestFallback:
+    """Priority 5: fallback to 'text'."""
+
+    def test_no_args(self) -> None:
+        assert detect_type() == "text"
+
+    def test_none_everything(self) -> None:
+        assert detect_type(path=None, content=None, explicit_type=None) == "text"
+
+
+class TestExtensionMapCompleteness:
+    """Verify EXTENSION_MAP entries are valid."""
+
+    def test_all_extensions_are_strings(self) -> None:
+        for ext, lexer in EXTENSION_MAP.items():
+            assert isinstance(ext, str), f"Key {ext!r} is not str"
+            assert isinstance(lexer, str), f"Value for {ext!r} is not str"
+
+    def test_all_extensions_start_with_dot(self) -> None:
+        for ext in EXTENSION_MAP:
+            assert ext.startswith("."), f"Extension {ext!r} doesn't start with '.'"
+
+    def test_all_filenames_in_filename_map(self) -> None:
+        for name in _FILENAME_MAP:
+            assert isinstance(name, str)
+
+    def test_filename_map_matches_path_name_lookup(self, tmp_file) -> None:
+        for name, expected in _FILENAME_MAP.items():
+            path = tmp_file("content", name=name)
+            assert detect_type(path=str(path)) == expected
+
+
+def test_path_stringified_from_pathlib(tmp_file) -> None:
+    path = tmp_file('print("hi")\n', suffix=".py")
+    assert detect_type(path=str(Path(path))) == "python"