Case fetching by ID #2714

data-serving/reusable-data-service/reusable_data_service/__init__.py

@@ -1,3 +1,5 @@
 __version__ = '0.1.0'
 
 from .model.case import Case
+from .controller.case_controller import CaseController
+from .main import app

data-serving/reusable-data-service/reusable_data_service/controller/case_controller.py

@@ -0,0 +1,18 @@
+from flask import jsonify
+
+class CaseController:
+    """Implements CRUD operations on cases. Uses an external store
+    class to actually work with the cases collection, so that different
+    storage technology can be chosen.
+    All methods return a tuple of (response, HTTP status code)"""
+    def __init__(self, store):
+        self._store = store
+
+    def get_case(self, id: str):
+        """Implements get /cases/:id. Interpretation of ID is dependent
+        on the store implementation but here it is an opaque token that
+        should be unique to each case."""
+        case = self._store.case_by_id(id)
+        if case is None:
+            return f"No case with ID {id}", 404
+        return jsonify(case), 200

data-serving/reusable-data-service/reusable_data_service/main.py

@@ -0,0 +1,3 @@
+from flask import Flask
+
+app = Flask(__name__)

data-serving/reusable-data-service/tests/test_case_controller.py

@@ -0,0 +1,39 @@
+import pytest
+
+from reusable_data_service import Case, CaseController, app
+
+
+class MemoryStore:
+    """Simple dictionary-based store for cases."""
+    def __init__(self):
+        self.cases = dict()
+
+    def case_by_id(self, id: str):
+        return self.cases.get(id)
+
+    def put_case(self, id: str, case: Case):
+        self.cases[id] = case
+
+
+@pytest.fixture
+def app_context():
+    with app.app_context():
+        yield
+
+
+def test_one_present_item_should_return_200_OK(app_context):
+    store = MemoryStore()
+    with open('./tests/data/case.minimal.json', 'r') as minimal_file:
+        case = Case.from_json(minimal_file.read())
+        store.put_case('foo', case)
+    controller = CaseController(store)
+    (response, status) = controller.get_case('foo')
+    assert status == 200
+    assert response is not None
+
+def test_one_absent_item_should_return_400_not_found(app_context):
+    store = MemoryStore()
+    controller = CaseController(store)
+    (response, status) = controller.get_case('foo')
+    assert status == 404
+    assert response == "No case with ID foo"