Mark untestable lines "no cover"

.coveragerc

@@ -2,5 +2,7 @@
 plugins = Cython.Coverage
 
 [report]
+exclude_lines =
+  pragma: no cover
 include =
   src/*

src/mbedtls/_md.pyx

@@ -116,12 +116,12 @@ cdef class MDBase:
         cdef unsigned char* output = <unsigned char*>malloc(
             sz * sizeof(unsigned char))
         if not output:
-            raise MemoryError()
+            raise MemoryError()  # pragma: no cover
         try:
             check_error(self._finish(output))
             return bytes(output[:self.digest_size])
         finally:
-            free(output)
+            free(output)  # pragma: no cover
 
     def hexdigest(self):
         """Like digest except the digest is returned as a string object
@@ -132,7 +132,7 @@ cdef class MDBase:
 
     def copy(self):
         """Return a copy ("clone") of the MD object."""
-        raise NotImplementedError
+        raise NotImplementedError  # pragma: no cover
 
 
 cdef class Hash(_md.MDBase):
@@ -229,4 +229,4 @@ cdef class Hmac(_md.MDBase):
             Not implemented in mbed TLS, raises NotImplementedError.
 
         """
-        raise NotImplementedError
+        raise NotImplementedError  # pragma: no cover

src/mbedtls/_random.pyx

@@ -39,12 +39,12 @@ cdef class _Entropy:
             length * sizeof(unsigned char)
         )
         if not output:
-            raise MemoryError()
+            raise MemoryError()  # pragma: no cover
         try:
             check_error(_rnd.mbedtls_entropy_func(&self._ctx, output, length))
             return bytes(output[:length])
         finally:
-            free(output)
+            free(output)  # pragma: no cover
 
     def update(self, const unsigned char[:] data):
         """Add data to the accumulator manually."""
@@ -85,7 +85,7 @@ cdef class Random:
             length * sizeof(unsigned char)
         )
         if not output:
-            raise MemoryError()
+            raise MemoryError()  # pragma: no cover
         try:
             check_error(
                 _rnd.mbedtls_ctr_drbg_random(&self._ctx, output, length)
@@ -94,7 +94,7 @@ cdef class Random:
             _plt.mbedtls_platform_zeroize(output, length)
             return ret
         finally:
-            free(output)
+            free(output)  # pragma: no cover
 
     def _reseed(self, const unsigned char[:] data=None):
         """Reseed the RNG."""

src/mbedtls/exceptions.pyx

@@ -32,7 +32,7 @@ class TLSError(Exception):
         cdef size_t buflen = 200
         cdef char* buffer = <char*>malloc(buflen * sizeof(char))
         if not buffer:
-            raise MemoryError()
+            raise MemoryError()  # pragma: no cover
         try:
             _err.mbedtls_strerror(self.err, &buffer[0], buflen)
             output = bytes(buffer[:buflen])
@@ -42,7 +42,7 @@ class TLSError(Exception):
                 olen = buflen
             return output[:olen].decode("ascii")
         finally:
-            free(buffer)
+            free(buffer)  # pragma: no cover
 
     def __str__(self):
         if self.err is None:

src/mbedtls/hkdf.pyx

@@ -48,7 +48,7 @@ def hkdf(
         length * sizeof(unsigned char)
     )
     if not okm:
-        raise MemoryError()
+        raise MemoryError()  # pragma: no cover
     try:
         check_error(_hkdf.mbedtls_hkdf(
             hmac._info,
@@ -61,7 +61,7 @@ def hkdf(
         ))
         return bytes(okm[:length])
     finally:
-        free(okm)
+        free(okm)  # pragma: no cover
 
 
 def extract(
@@ -94,7 +94,7 @@ def extract(
         hmac.digest_size * sizeof(unsigned char)
     )
     if not prk:
-        raise MemoryError()
+        raise MemoryError()  # pragma: no cover
     try:
         check_error(_hkdf.mbedtls_hkdf_extract(
             hmac._info,
@@ -105,7 +105,7 @@ def extract(
         ))
         return bytes(prk[:hmac.digest_size])
     finally:
-        free(prk)
+        free(prk)  # pragma: no cover
 
 
 def expand(
@@ -139,7 +139,7 @@ def expand(
         length * sizeof(unsigned char)
     )
     if not okm:
-        raise MemoryError()
+        raise MemoryError()  # pragma: no cover
     try:
         check_error(_hkdf.mbedtls_hkdf_expand(
             hmac._info,
@@ -150,4 +150,4 @@ def expand(
         ))
         return bytes(okm[:length])
     finally:
-        free(okm)
+        free(okm)  # pragma: no cover

src/mbedtls/mpi.pxd

@@ -114,7 +114,7 @@ cdef class MPI:
     cdef size_t _len(self)
 
 
-cdef inline from_mpi(mbedtls_mpi *c_mpi):
+cdef inline from_mpi(mbedtls_mpi *c_mpi):  # pragma: no cover
     new_mpi = MPI()
     mbedtls_mpi_copy(&new_mpi._ctx, c_mpi)
     return new_mpi

src/mbedtls/mpi.pyx

@@ -99,15 +99,15 @@ cdef class MPI:
         cdef unsigned char* output = <unsigned char*>malloc(
             length * sizeof(unsigned char))
         if not output:
-            raise MemoryError()
+            raise MemoryError()  # pragma: no cover
         try:
             check_error(_mpi.mbedtls_mpi_write_binary(
                 &self._ctx, output, length))
             return bytes(output[:length])[::-1 if byteorder == "little" else 1]
         except Exception as exc:
             raise OverflowError from exc
         finally:
-            free(output)
+            free(output)  # pragma: no cover
 
     __bytes__ = to_bytes