Additional exceptions tests for bad args and failing .NET runtime

Author: masaccio

tests/conftest.py

@@ -1,3 +1,28 @@
+from pathlib import Path
+
+import pytest
+import pythonnet
+
+
 def pytest_addoption(parser):
     parser.addoption("--test-file", action="store", default=None)
     parser.addoption("--test-verbose", action="store_true", default=False)
+
+
+@pytest.fixture
+def path_is_file_fails(monkeypatch):
+    """Make Path.is_file return False so load_runtime will raise FileNotFoundError."""
+    monkeypatch.setattr(Path, "is_file", lambda self: False)
+
+
+@pytest.fixture
+def pythonnet_load_raises(monkeypatch):
+    """Make pythonnet.load raise RuntimeError while keeping the DLL present."""
+    monkeypatch.setattr(Path, "is_file", lambda self: True)
+
+    def _raise(runtime) -> None:
+        _ = runtime
+        msg = "failed to init runtime"
+        raise RuntimeError(msg)
+
+    monkeypatch.setattr(pythonnet, "load", _raise)

tests/test_formatter.py

@@ -1,3 +1,5 @@
+import importlib
+import sys
 from pathlib import Path
 
 import pytest
@@ -98,3 +100,45 @@ def test_exceptions():
         match=r"Invalid value 'EolStyle\.CRLF' for option comment_policy",
     ):
         _ = FracturedJsonOptions(comment_policy=EolStyle.CRLF)
+    formatter = Formatter()
+    with pytest.raises(TypeError, match="json_text must be a str"):
+        formatter.reformat(None)  # type: ignore[arg-type]
+
+    with pytest.raises(TypeError, match="json_text must be a str"):
+        formatter.minify(b"{}")  # type: ignore[arg-type]
+
+    with pytest.raises(TypeError, match="Must be callable"):
+        formatter.string_length_func = 123  # type: ignore[assignment]
+
+
+def test_dll_missing(path_is_file_fails):  # noqa: ARG001
+    if "fractured_json" in sys.modules:
+        del sys.modules["fractured_json"]
+
+    with pytest.raises(FileNotFoundError) as exc:
+        importlib.import_module("fractured_json")
+
+    assert "FracturedJson.dll not found" in str(exc.value)
+
+
+def test_load_runtime_fails(pythonnet_load_raises):  # noqa: ARG001
+    if "fractured_json" in sys.modules:
+        del sys.modules["fractured_json"]
+
+    with pytest.raises(RuntimeError) as exc:
+        importlib.import_module("fractured_json")
+
+    assert "Failed to load pythonnet runtime" in str(exc.value)
+    assert "coreclr" in str(exc.value)
+
+
+def test_string_length_property():
+    formatter = Formatter()
+
+    def double_len(s: str) -> int:
+        return len(s) * 2
+
+    formatter.string_length_func = double_len
+    getter = formatter.string_length_func
+    assert callable(getter)
+    assert getter("abc") == 6