test failure / encrypt decrypt

tests/test_cipher.py

@@ -124,29 +124,43 @@ def data(self, cipher, mode, randbytes):
         # `block_size` is limited for ECB because it is a block cipher.
         return randbytes(cipher.block_size if mode is mb.Mode.ECB else 20000)
 
-    def test_unsupported_mode(self, module, key, unsupported_mode, iv):
-        with pytest.raises(TLSError):
-            module.new(key, unsupported_mode, iv)
-
     def test_mode_accessor(self, cipher, mode):
         assert cipher.mode is mode
 
     def test_iv_size_accessor(self, cipher, iv_size):
         assert cipher.iv_size == iv_size
 
-    def test_invalid_key_size(self, module, invalid_key, mode, iv):
-        with pytest.raises(TLSError):
-            module.new(invalid_key, mode, iv)
-
     def test_key_size_accessor(self, cipher, key_size):
         assert cipher.key_size == key_size
 
     def test_name_accessor(self, cipher):
         assert cipher.name in CIPHER_NAME
 
+    def test_str(self, cipher):
+        assert str(cipher) == cipher.name.decode("ascii")
+
+    def test_type_accessor(self, cipher):
+        assert CIPHER_NAME[cipher._type] == cipher.name
+
+    def test_unsupported_mode(self, module, key, unsupported_mode, iv):
+        with pytest.raises(TLSError):
+            module.new(key, unsupported_mode, iv)
+
+    def test_invalid_key_size(self, module, invalid_key, mode, iv):
+        with pytest.raises(TLSError):
+            module.new(invalid_key, mode, iv)
+
     def test_encrypt_decrypt(self, cipher, data):
         assert cipher.decrypt(cipher.encrypt(data)) == data
 
+    def test_encrypt_nothing_raises(self, cipher):
+        with pytest.raises(TLSError):
+            cipher.encrypt(b"")
+
+    def test_decrypt_nothing_raises(self, cipher):
+        with pytest.raises(TLSError):
+            cipher.decrypt(b"")
+
     def test_module_level_block_size(self, module, cipher):
         assert module.block_size == cipher.block_size
 
@@ -167,6 +181,11 @@ def test_encrypt_decrypt(self, cipher, data):
         msg, tag = cipher.encrypt(data)
         assert cipher.decrypt(msg, tag) == data
 
+    def test_decrypt_nothing_raises(self, cipher, data):
+        msg, tag = cipher.encrypt(data)
+        with pytest.raises(TLSError):
+            cipher.decrypt(b"", tag)
+
 
 @pytest.mark.skipif(
     not mbedtls.has_feature("aes"), reason="requires AES support in libmbedtls"