Address review comments

Author: gf712

src/runtime/modules/BuiltinsModule.cpp

@@ -114,7 +114,7 @@ PyResult<PyObject *> print(const PyTuple *args, const PyDict *kwargs, Interprete
 		if (auto it = kwargs->map().find(file_keyword); it != kwargs->map().end()) {
 			auto file_ = PyObject::from(it->second);
 			if (file_.is_err()) { return file_; }
-			file = file_.unwrap();
+			if (file_.unwrap() != py_none()) { file = file_.unwrap(); }
 		}
 		if (auto it = kwargs->map().find(flush_keyword); it != kwargs->map().end()) {
 			auto flush_ = PyObject::from(it->second);

src/runtime/modules/IOModule.cpp

@@ -990,10 +990,15 @@ struct Buffered
 	{
 		if (auto err = check_initialized(); err.is_err()) return Err(err.unwrap_err());
 
-		if (n < -1) { return Err(value_error("read length must be non-negative or -1")); }
+		if (n < 0) {
+			// TODO: determine actual buffer size
+			n = 4096;
+		}
 
 		if (is_closed()) { return Err(value_error("read of closed file")); }
 
+		if (n == 0) { return PyBytes::create(); }
+
 		const auto have = readahead();
 		if (have > 0) { return static_cast<T *>(this)->readfast(n); }
 		Bytes b;
@@ -3133,7 +3138,12 @@ class TextIOWrapper : public TextIOBase
 		while (!m_buffer_bytes.has_value() || m_buffer_bytes->b.empty()) {
 			auto chunk = read_chunk(0);
 			if (chunk.is_err()) { return Err(chunk.unwrap_err()); }
-			if (chunk.unwrap() == 0) { break; }
+			if (!chunk.unwrap()) { break; }
+		}
+
+		if (!m_buffer_bytes.has_value()) {
+			// EOF
+			return PyString::create("");
 		}
 
 		std::string_view remaining{ bit_cast<const char *>(m_buffer_bytes->b.data()) + m_position,