add exception hierarchy pytests

Author: davidhewitt

pytests/src/exceptions.rs

@@ -0,0 +1,76 @@
+use pyo3::exceptions::PyException;
+use pyo3::prelude::*;
+use pyo3::types::{PyDict, PyTuple};
+
+#[pyclass(extends=PyException, subclass)]
+struct CustomException {}
+
+#[pymethods]
+impl CustomException {
+    #[new]
+    #[pyo3(signature = (*_args, **_kwargs))]
+    fn new(_args: &PyTuple, _kwargs: Option<&PyDict>) -> PyClassInitializer<Self> {
+        PyClassInitializer::from(CustomException {})
+    }
+}
+
+#[pyclass(extends=CustomException, subclass)]
+struct ExceptionSubclassA {}
+
+#[pymethods]
+impl ExceptionSubclassA {
+    #[new]
+    #[pyo3(signature = (*args, **kwargs))]
+    fn new(args: &PyTuple, kwargs: Option<&PyDict>) -> PyClassInitializer<Self> {
+        CustomException::new(args, kwargs).add_subclass(Self {})
+    }
+}
+
+#[pyclass(extends=ExceptionSubclassA, subclass)]
+struct ExceptionSubclassAChild {}
+
+#[pymethods]
+impl ExceptionSubclassAChild {
+    #[new]
+    #[pyo3(signature = (*args, **kwargs))]
+    fn new(args: &PyTuple, kwargs: Option<&PyDict>) -> PyClassInitializer<Self> {
+        ExceptionSubclassA::new(args, kwargs).add_subclass(Self {})
+    }
+}
+
+#[pyclass(extends=CustomException)]
+struct ExceptionSubclassB {}
+
+#[pymethods]
+impl ExceptionSubclassB {
+    #[new]
+    #[pyo3(signature = (*args, **kwargs))]
+    fn new(args: &PyTuple, kwargs: Option<&PyDict>) -> PyClassInitializer<Self> {
+        CustomException::new(args, kwargs).add_subclass(Self {})
+    }
+}
+
+#[pyfunction]
+fn do_something(op: &str) -> PyResult<()> {
+    match op {
+        "success" => Ok(()),
+
+        "subclass_a" => Err(PyErr::new::<ExceptionSubclassA, _>("subclass_a")),
+        "subclass_a_child" => Err(PyErr::new::<ExceptionSubclassAChild, _>("subclass_a_child")),
+        "subclass_b" => Err(PyErr::new::<ExceptionSubclassB, _>("subclass_b")),
+        _ => Err(PyErr::new::<CustomException, _>(format!(
+            "unknown op `{}`",
+            op
+        ))),
+    }
+}
+
+#[pymodule]
+pub fn exceptions(_py: Python<'_>, m: &PyModule) -> PyResult<()> {
+    m.add_class::<CustomException>()?;
+    m.add_class::<ExceptionSubclassA>()?;
+    m.add_class::<ExceptionSubclassAChild>()?;
+    m.add_class::<ExceptionSubclassB>()?;
+    m.add_function(wrap_pyfunction!(do_something, m)?)?;
+    Ok(())
+}

pytests/src/lib.rs

@@ -7,6 +7,7 @@ pub mod buf_and_str;
 pub mod comparisons;
 pub mod datetime;
 pub mod dict_iter;
+pub mod exceptions;
 pub mod misc;
 pub mod objstore;
 pub mod othermod;
@@ -25,6 +26,7 @@ fn pyo3_pytests(py: Python<'_>, m: &PyModule) -> PyResult<()> {
     #[cfg(not(Py_LIMITED_API))]
     m.add_wrapped(wrap_pymodule!(datetime::datetime))?;
     m.add_wrapped(wrap_pymodule!(dict_iter::dict_iter))?;
+    m.add_wrapped(wrap_pymodule!(exceptions::exceptions))?;
     m.add_wrapped(wrap_pymodule!(misc::misc))?;
     m.add_wrapped(wrap_pymodule!(objstore::objstore))?;
     m.add_wrapped(wrap_pymodule!(othermod::othermod))?;
@@ -44,6 +46,7 @@ fn pyo3_pytests(py: Python<'_>, m: &PyModule) -> PyResult<()> {
     sys_modules.set_item("pyo3_pytests.comparisons", m.getattr("comparisons")?)?;
     sys_modules.set_item("pyo3_pytests.datetime", m.getattr("datetime")?)?;
     sys_modules.set_item("pyo3_pytests.dict_iter", m.getattr("dict_iter")?)?;
+    sys_modules.set_item("pyo3_pytests.exceptions", m.getattr("exceptions")?)?;
     sys_modules.set_item("pyo3_pytests.misc", m.getattr("misc")?)?;
     sys_modules.set_item("pyo3_pytests.objstore", m.getattr("objstore")?)?;
     sys_modules.set_item("pyo3_pytests.othermod", m.getattr("othermod")?)?;

pytests/tests/test_exceptions.py

@@ -0,0 +1,26 @@
+from pyo3_pytests import exceptions
+import pytest
+
+
+def test_exceptions():
+    assert exceptions.do_something("success") is None
+
+    with pytest.raises(exceptions.CustomException) as exc_info:
+        exceptions.do_something("fail")
+
+    assert exc_info.value.args == ("unknown op `fail`",)
+
+    with pytest.raises(exceptions.ExceptionSubclassA) as exc_info:
+        exceptions.do_something("subclass_a")
+
+    assert exc_info.value.args == ("subclass_a",)
+
+    with pytest.raises(exceptions.ExceptionSubclassAChild) as exc_info:
+        exceptions.do_something("subclass_a_child")
+
+    assert exc_info.value.args == ("subclass_a_child",)
+
+    with pytest.raises(exceptions.ExceptionSubclassB) as exc_info:
+        exceptions.do_something("subclass_b")
+
+    assert exc_info.value.args == ("subclass_b",)