diff --git a/CHANGES.md b/CHANGES.md
index e1aec45..847f7d8 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -10,7 +10,7 @@
 public_key)`
 - When operations fail (i.e., `OQS_SUCCESS != 0`) in functions returning
   non-boolean objects, a `RuntimeError` is now raised, instead of returning 0
-- Bugfix on Linux, `c_int` -> `c_size_t` for buffer sizes
+- Bugfix on Linux platforms, `c_int` -> `c_size_t` for buffer sizes
 - Pyright type checking fixes
 - Updated examples to use `ML-KEM` and `ML-DSA` as the defaults
 
diff --git a/oqs/oqs.py b/oqs/oqs.py
index e57ce89..f75aa38 100644
--- a/oqs/oqs.py
+++ b/oqs/oqs.py
@@ -110,10 +110,10 @@ def _install_liboqs(target_directory, oqs_version=None):
 def _load_liboqs():
     if "OQS_INSTALL_PATH" in os.environ:
         oqs_install_dir = os.path.abspath(os.environ["OQS_INSTALL_PATH"])
-    else:    
+    else:
         home_dir = os.path.expanduser("~")
         oqs_install_dir = os.path.abspath(home_dir + os.path.sep + "_oqs")  # $HOME/_oqs
-        
+
     oqs_lib_dir = (
         os.path.abspath(oqs_install_dir + os.path.sep + "bin")  # $HOME/_oqs/bin
         if platform.system() == "Windows"
@@ -122,10 +122,14 @@ def _load_liboqs():
     oqs_lib64_dir = (
         os.path.abspath(oqs_install_dir + os.path.sep + "bin")  # $HOME/_oqs/bin
         if platform.system() == "Windows"
-        else os.path.abspath(oqs_install_dir + os.path.sep + "lib64")  # $HOME/_oqs/lib64
+        else os.path.abspath(
+            oqs_install_dir + os.path.sep + "lib64"
+        )  # $HOME/_oqs/lib64
     )
     try:
-        _liboqs = _load_shared_obj(name="oqs", additional_searching_paths=[oqs_lib_dir, oqs_lib64_dir])
+        _liboqs = _load_shared_obj(
+            name="oqs", additional_searching_paths=[oqs_lib_dir, oqs_lib64_dir]
+        )
         assert _liboqs
     except RuntimeError:
         # We don't have liboqs, so we try to install it automatically
@@ -462,18 +466,18 @@ def sign(self, message):
         c_signature = ct.create_string_buffer(self._sig.contents.length_signature)
 
         # Initialize to maximum signature size
-        signature_len = ct.c_size_t(self._sig.contents.length_signature)
+        c_signature_len = ct.c_size_t(self._sig.contents.length_signature)
 
         rv = native().OQS_SIG_sign(
             self._sig,
             ct.byref(c_signature),
-            ct.byref(signature_len),
+            ct.byref(c_signature_len),
             c_message,
             c_message_len,
             self.secret_key,
         )
         if rv == OQS_SUCCESS:
-            return bytes(c_signature[: signature_len.value])
+            return bytes(c_signature[: c_signature_len.value])
         else:
             raise RuntimeError("Can not sign message")
 
@@ -489,7 +493,7 @@ def verify(self, message, signature, public_key):
         c_message = ct.create_string_buffer(message, len(message))
         c_message_len = ct.c_size_t(len(c_message))
         c_signature = ct.create_string_buffer(signature, len(signature))
-        signature_len = ct.c_size_t(len(c_signature))
+        c_signature_len = ct.c_size_t(len(c_signature))
         c_public_key = ct.create_string_buffer(
             public_key, self._sig.contents.length_public_key
         )
@@ -499,7 +503,7 @@ def verify(self, message, signature, public_key):
             c_message,
             c_message_len,
             c_signature,
-            signature_len,
+            c_signature_len,
             c_public_key,
         )
         return True if rv == OQS_SUCCESS else False
@@ -511,16 +515,22 @@ def sign_with_ctx_str(self, message, context):
         :param context: the context string.
         :param message: the message to sign.
         """
+        if context and not self._sig.contents.sig_with_ctx_support:
+            raise RuntimeError("Signing with context string not supported")
+
         # Provide length to avoid extra null char
         c_message = ct.create_string_buffer(message, len(message))
         c_message_len = ct.c_size_t(len(c_message))
-        c_context = ct.create_string_buffer(context, len(context))
-        context_len = ct.c_size_t(len(c_context))
+        if len(context) == 0:
+            c_context = None
+            c_context_len = 0
+        else:
+            c_context = ct.create_string_buffer(context, len(context))
+            c_context_len = ct.c_size_t(len(c_context))
         c_signature = ct.create_string_buffer(self._sig.contents.length_signature)
 
         # Initialize to maximum signature size
         c_signature_len = ct.c_size_t(self._sig.contents.length_signature)
-
         rv = native().OQS_SIG_sign_with_ctx_str(
             self._sig,
             ct.byref(c_signature),
@@ -528,7 +538,7 @@ def sign_with_ctx_str(self, message, context):
             c_message,
             c_message_len,
             c_context,
-            context_len,
+            c_context_len,
             self.secret_key,
         )
         if rv == OQS_SUCCESS:
@@ -545,13 +555,20 @@ def verify_with_ctx_str(self, message, signature, context, public_key):
         :param context: the context string.
         :param public_key: the signer's public key.
         """
+        if context and not self._sig.contents.sig_with_ctx_support:
+            raise RuntimeError("Verifying with context string not supported")
+
         # Provide length to avoid extra null char
         c_message = ct.create_string_buffer(message, len(message))
         c_message_len = ct.c_size_t(len(c_message))
         c_signature = ct.create_string_buffer(signature, len(signature))
         c_signature_len = ct.c_size_t(len(c_signature))
-        c_context = ct.create_string_buffer(context, len(context))
-        c_context_len = ct.c_size_t(len(c_context))
+        if len(context) == 0:
+            c_context = None
+            c_context_len = 0
+        else:
+            c_context = ct.create_string_buffer(context, len(context))
+            c_context_len = ct.c_size_t(len(c_context))
         c_public_key = ct.create_string_buffer(
             public_key, self._sig.contents.length_public_key
         )
diff --git a/tests/test_kem.py b/tests/test_kem.py
index 7733666..ca4fa52 100644
--- a/tests/test_kem.py
+++ b/tests/test_kem.py
@@ -6,7 +6,7 @@
 disabled_KEM_patterns = []
 
 if platform.system() == "Windows":
-    disabled_KEM_patterns = ["Classic-McEliece"]
+    disabled_KEM_patterns = [""]
 
 
 def test_correctness():
@@ -47,7 +47,7 @@ def check_wrong_ciphertext(alg_name):
 
 def test_not_supported():
     try:
-        with oqs.KeyEncapsulation("bogus"):
+        with oqs.KeyEncapsulation("unsupported_sig"):
             raise AssertionError("oqs.MechanismNotSupportedError was not raised.")
     except oqs.MechanismNotSupportedError:
         pass
@@ -56,7 +56,6 @@ def test_not_supported():
 
 
 def test_not_enabled():
-    # TODO: test broken as the compiled lib determines which algorithms are supported and enabled
     for alg_name in oqs.get_supported_kem_mechanisms():
         if alg_name not in oqs.get_enabled_kem_mechanisms():
             # Found a non-enabled but supported alg
diff --git a/tests/test_sig.py b/tests/test_sig.py
index f84ef4b..57c406a 100644
--- a/tests/test_sig.py
+++ b/tests/test_sig.py
@@ -92,7 +92,7 @@ def check_wrong_public_key(alg_name):
 
 def test_not_supported():
     try:
-        with oqs.Signature("bogus"):
+        with oqs.Signature("unsupported_sig"):
             raise AssertionError("oqs.MechanismNotSupportedError was not raised.")
     except oqs.MechanismNotSupportedError:
         pass
@@ -101,7 +101,6 @@ def test_not_supported():
 
 
 def test_not_enabled():
-    # TODO: test broken as the compiled lib determines which algorithms are supported and enabled
     for alg_name in oqs.get_supported_sig_mechanisms():
         if alg_name not in oqs.get_enabled_sig_mechanisms():
             # Found a non-enabled but supported alg