add missing basket examples (#542)

Co-authored-by: Michael R. Crusoe <michael.crusoe@gmail.com>

schema_salad/tests/basket.yml

@@ -1,9 +1,9 @@
-# N.B.: this example is used in a test that needs a file without $base,
-#       so please do not include $base here.
-- name: Basket
-  doc: A basket of products.
-  type: record
-  documentRoot: true
-  fields:
-    product: string
-    price: float
+basket:
+  - product: bananas
+    price: 0.39
+    per: pound
+    weight: 1
+  - product: cucumbers
+    price: 0.79
+    per: item
+    count: 3

schema_salad/tests/basket_schema.yml

@@ -0,0 +1,54 @@
+# N.B.: this example is used in a test that needs a file without $base,
+#       so please do not include $base here.
+- name: Product
+  doc: |
+    The base type for a product.  This is an abstract type, so it
+    can't be used directly, but can be used to define other types.
+  type: record
+  abstract: true
+  fields:
+    product: string
+    price: float
+
+- name: ByWeight
+  doc: |
+    A product, sold by weight.  Products may be sold by pound or by
+    kilogram.  Weights may be fractional.
+  type: record
+  extends: Product
+  fields:
+    per:
+      type:
+        type: enum
+        symbols:
+          - pound
+          - kilogram
+      jsonldPredicate: "#per"
+    weight: float
+
+- name: ByCount
+  doc: |
+    A product, sold by count.  The count must be a integer value.
+  type: record
+  extends: Product
+  fields:
+    per:
+      type:
+        type: enum
+        symbols:
+          - item
+      jsonldPredicate: "#per"
+    count: int
+
+- name: Basket
+  doc: |
+    A basket of products.  The 'documentRoot' field indicates it is a
+    valid starting point for a document.  The 'basket' field will
+    validate subtypes of 'Product' (ByWeight and ByCount).
+  type: record
+  documentRoot: true
+  fields:
+    basket:
+      type:
+        type: array
+        items: Product

schema_salad/tests/util.py

@@ -40,4 +40,4 @@ def get_data_uri(resource_path: str) -> str:
 
 cwl_file_uri = get_data_uri("tests/test_schema/CommonWorkflowLanguage.yml")
 metaschema_file_uri = get_data_uri("metaschema/metaschema.yml")
-basket_file_uri = get_data_uri("basket.yml")
+basket_file_uri = get_data_uri("tests/basket_schema.yml")