Added test case (skipped due to issue in dependency)

tests/test_field_types.py

@@ -1,6 +1,6 @@
 from dataclasses import dataclass, field
 from pathlib import Path
-from typing import Union
+from typing import Optional, Union
 
 import pytest
 from config_classes import LongConfig as Config
@@ -153,3 +153,25 @@ def func(config: NonInitConfig):
         ],
         global_config=global_config,
     )
+
+
+@pytest.mark.skip(
+    reason="issue within dependency (see: https://github.com/konradhalas/dacite/issues/244 )"
+)
+def test_non_init_optional_field(global_config):
+    @dataclass
+    class NonInitConfig:
+        a: int
+        b: Optional[float] = field(init=False)
+
+        def __post_init__(self):
+            self.b = float(self.a)
+
+    def func(config: NonInitConfig):
+        assert int(config.b) == config.a
+
+    cordage.run(func, args=["--a", "2"], global_config=global_config)
+
+    # Invoking the command with b should make the parser exit
+    with pytest.raises(SystemExit):
+        cordage.run(func, args=["--a", "2", "--b", "3"], global_config=global_config)