fix(misc): fix multiple issues

README.md

@@ -17,6 +17,8 @@ Python tools for MODFLOW development and testing.
     - [Test models](#test-models)
     - [Example scenarios](#example-scenarios)
   - [Reusable test case framework](#reusable-test-case-framework)
+    - [Parametrizing with `Case`](#parametrizing-with-case)
+    - [Generating cases dynamically](#generating-cases-dynamically)
   - [Executables container](#executables-container)
   - [Conditionally skipping tests](#conditionally-skipping-tests)
   - [Miscellaneous](#miscellaneous)
@@ -155,22 +157,57 @@ This package provides a minimal framework for self-describing test cases which c
 
 A `Case` requires only a `name`, and has a single default attribute, `xfail=False`, indicating whether the test case is expected to succeed. (Test functions may of course choose to use or ignore this.)
 
-For instance, to generate a set of similar test cases with `pytest-cases`:
+#### Parametrizing with `Case`
 
-```python
-from pytest_cases import parametrize
+`Case` can be used with `@pytest.mark.parametrize()` as usual. For instance:
 
+```python
+import pytest
 from modflow_devtools.case import Case
 
 template = Case(name="QA")
 cases = [
-  template.copy_update(name=template.name + "1", question="What's the meaning of life, the universe, and everything?", answer=42),
-  template.copy_update(name=template.name + "2", question="Is a Case immutable?", answer="No, but it's better not to mutate it.")
+    template.copy_update(name=template.name + "1",
+                         question="What's the meaning of life, the universe, and everything?",
+                         answer=42),
+    template.copy_update(name=template.name + "2",
+                         question="Is a Case immutable?",
+                         answer="No, but it's probably best not to mutate it.")
 ]
 
-@parametrize(data=cases, ids=[c.name for c in cases])
-def case_qa(case):
-    print(case.name, case.question, case.answer)
+
+@pytest.mark.parametrize("case", cases)
+def test_cases(case):
+    assert len(cases) == 2
+    assert cases[0] != cases[1]
+```
+
+#### Generating cases dynamically
+
+One pattern possible with `pytest-cases` is to programmatically generate test cases by parametrizing a function. This can be a convenient way to produce several similar test cases from a template:
+
+```python
+from pytest_cases import parametrize, parametrize_with_cases
+from modflow_devtools.case import Case
+
+
+template = Case(name="QA")
+gen_cases = [template.copy_update(name=f"{template.name}{i}", question=f"Q{i}", answer=f"A{i}") for i in range(3)]
+info = "cases can be modified further in the generator function,"\
+       " or the function may construct and return another object"
+
+
+@parametrize(case=gen_cases, ids=[c.name for c in gen_cases])
+def qa_cases(case):
+    return case.copy_update(info=info)
+
+
+@parametrize_with_cases("case", cases=".", prefix="qa_")
+def test_qa(case):
+    assert "QA" in case.name
+    assert info == case.info
+    print(f"{case.name}:", f"{case.question}? {case.answer}")
+    print(case.info)
 ```
 
 ### Executables container

modflow_devtools/case.py

@@ -6,7 +6,11 @@ class Case(SimpleNamespace):
     Minimal container for a reusable test case.
     """
 
-    def __init__(self, **kwargs):
+    def __init__(self, case: "Case" = None, **kwargs):
+        if case is not None:
+            super().__init__(**case.__dict__.copy())
+            return
+
         if "name" not in kwargs:
             raise ValueError(f"Case name is required")
 
@@ -26,7 +30,7 @@ def copy(self):
         Copies the test case.
         """
 
-        return SimpleNamespace(**self.__dict__.copy())
+        return Case(**self.__dict__.copy())
 
     def copy_update(self, **kwargs):
         """
@@ -36,4 +40,4 @@ def copy_update(self, **kwargs):
 
         cpy = self.__dict__.copy()
         cpy.update(kwargs)
-        return SimpleNamespace(**cpy)
+        return Case(**cpy)