PyO3 exposes much of python's C api through the ffi.

The C api is naturally unsafe and requires you to manage reference counts, errors and specific invariants yourself. Please refer to the C API Reference Manual and The Rustonomicon before using any function from that api.

Currently, #341 causes cargo test to fail with weird linking errors when the extension-module feature is activated. For nnow you can work around this by making the extension-module feature optional and running the tests with cargo test --no-default-features:

[dependencies.pyo3]
version = "0.6.0"

[features]
extension-module = ["pyo3/extension-module"]
default = ["extension-module"]