Add ABC for views

Author: liammulh

TODO.md

@@ -19,18 +19,18 @@
     - For example, `views/new_allele.py` should be `views/allele.py`.
     - [x] We've found all views where this refactor is needed.
     - [x] We've made the changes.
-        - [x] curations
-        - [x] diseases
-        - [x] home
-        - [x] markers
-        - [x] publications
-        - [x] users
-
-- [ ] Abstract base classes are in use.
-    - [ ] Clients implement an abstract base class.
-    - [ ] Selectors implement an abstract base class.
-    - [ ] Services implement an abstract base class.
-    - [ ] Views implement an abstract base class.
+
+- [ ] Abstract base classes have been created.
+    - [ ] We have an ABC for clients.
+    - [ ] We have an ABC for selectors.
+    - [ ] We have an ABC for services.
+    - [x] We have an ABC for views.
+
+- [ ] Abstract base views are in use.
+    - [ ] Clients implement an ABC.
+    - [ ] Selectors implement an ABC.
+    - [ ] Services implement an ABC.
+    - [ ] Views implement an ABC.
 
 ## The missing tests have been added.
 

src/base/__init__.py

@@ -0,0 +1,28 @@
+"""Provide base classes for views."""
+
+from abc import ABC, abstractmethod
+
+
+class EntityView(ABC):
+    """Provide an abstract base class for entity views.
+
+    Here an entity refers to a model in the HCI that has a new page, an all page,
+    and an overview page. Some examples include: curations, diseases, markers (alleles
+    and haplotypes), and publications.
+    """
+
+    @abstractmethod
+    def new(self) -> None:
+        """View the page that provides a form that creates a new entity."""
+
+    @abstractmethod
+    def all(self) -> None:
+        """View the searchable table page for an entity."""
+
+    @abstractmethod
+    def overview(self, human_readable_id: str) -> None:
+        """View the overview page for an entity.
+
+        Args:
+             human_readable_id: The human-readable ID of the model for the entity.
+        """