STORY : Added failing test for rewrite given feature.

Author: crdoconnor

hitch/story/rewrite-given.story

@@ -0,0 +1,68 @@
+Story that rewrites given preconditions:
+  docs: engine/rewrite-given
+  about: |
+    These examples show how to build stories that rewrite themselves
+    from program output (in-test snapshot testing) but that rewrite
+    the given preconditions.
+
+    This is useful for changing
+
+    ```
+    self.current_step.rewrite("argument").to("new output")
+    ```
+
+  given:
+    files:
+      example.story: |
+        Call API:
+          given:
+            mock api:
+              request: |
+                {"greeting": "hello"}
+              response: |
+                {"greeting": "hi"}
+          steps:
+            - Call API
+      engine.py: |
+        from hitchstory import BaseEngine, GivenDefinition, GivenProperty
+        from strictyaml import Map, Str
+
+        class Engine(BaseEngine):
+            given_definition = GivenDefinition(
+                mock_api=GivenProperty(
+                    schema=Map({"request": Str(), "response": Str()}),
+                    inherit_via=GivenProperty.OVERRIDE,
+                ),
+            )
+
+            def __init__(self, rewrite=True):
+                self._rewrite = rewrite
+            
+            def call_api(self):
+                if self._rewrite:
+                    self.given.rewrite("Mock API", "response").to("""{"greeting": "bye"}""")
+
+    setup: |
+      from hitchstory import StoryCollection
+      from pathlib import Path
+      from engine import Engine
+
+  steps:
+  - Run:
+      code: |
+        StoryCollection(Path(".").glob("*.story"), Engine(rewrite=True)).ordered_by_name().play()
+      will output: |-
+        RUNNING Call API in /path/to/working/example.story ... SUCCESS in 0.1 seconds.
+
+  - File contents will be:
+      filename: example.story
+      contents: |-
+        Call API:
+          given:
+            mock api:
+              request: |
+                {"greeting": "hello"}
+              response: |
+                {"greeting": "bye"}
+          steps:
+            - Call API