[Fusion] Added requirement tests (#9117)

Author: michaelstaib

src/HotChocolate/Fusion-vnext/src/Fusion.Execution.Types/Directives/FieldDirectiveParser.cs

@@ -34,13 +34,19 @@ public static FieldDirective Parse(DirectiveNode directive)
                     break;
 
                 case "provides":
-                    provides = Utf8GraphQLParser.Syntax.ParseSelectionSet(((StringValueNode)argument.Value).Value);
+                    var providesValue = ((StringValueNode)argument.Value).Value;
+                    provides = ParseProvidesSelectionSet(providesValue);
                     break;
 
                 case "external":
                     isExternal = ((BooleanValueNode)argument.Value).Value;
                     break;
 
+                case "partial":
+                    // `partial` is the composition-time encoding for external source fields.
+                    isExternal = ((BooleanValueNode)argument.Value).Value;
+                    break;
+
                 default:
                     throw new DirectiveParserException(
                         $"The argument `{argument.Name.Value}` is not supported on @field.");
@@ -56,6 +62,20 @@ public static FieldDirective Parse(DirectiveNode directive)
         return new FieldDirective(new SchemaKey(schemaKey), sourceName, sourceType, provides, isExternal);
     }
 
+    private static SelectionSetNode ParseProvidesSelectionSet(string value)
+    {
+        try
+        {
+            // Fusion schemas can encode provides either as a raw selection set (`{ id }`) or as
+            // the legacy field-set form (`id`).
+            return Utf8GraphQLParser.Syntax.ParseSelectionSet(value);
+        }
+        catch (SyntaxException)
+        {
+            return Utf8GraphQLParser.Syntax.ParseSelectionSet($"{{ {value} }}");
+        }
+    }
+
     public static ImmutableArray<FieldDirective> Parse(
         IReadOnlyList<DirectiveNode> directiveNodes)
     {

src/HotChocolate/Fusion-vnext/test/Fusion.Execution.Tests/Planning/EntityChainTests.cs

@@ -0,0 +1,207 @@
+using HotChocolate.Fusion.Types;
+
+namespace HotChocolate.Fusion.Planning;
+
+public class EntityChainTests : FusionTestBase
+{
+    [Fact]
+    public void Complex_Entity_Call()
+    {
+        // arrange
+        var schema = CreateComplexEntityCallSchema();
+
+        // act
+        var plan = PlanOperation(
+            schema,
+            """
+            {
+              topProducts {
+                products {
+                  id
+                  price {
+                    price
+                  }
+                }
+              }
+            }
+            """);
+
+        // assert
+        MatchSnapshot(plan);
+    }
+
+    [Fact]
+    public void Parent_Entity_Call_Complex()
+    {
+        // arrange
+        var schema = CreateParentEntityCallComplexSchema();
+
+        // act
+        var plan = PlanOperation(
+            schema,
+            """
+            query {
+              productFromD(id: "1") {
+                id
+                name
+                category {
+                  id
+                  name
+                  details
+                }
+              }
+            }
+            """);
+
+        // assert
+        MatchSnapshot(plan);
+    }
+
+    private static FusionSchemaDefinition CreateComplexEntityCallSchema()
+    {
+        return ComposeSchema(
+            """
+            # name: products
+            schema {
+              query: Query
+            }
+
+            type Query {
+              topProducts: ProductList!
+            }
+
+            type ProductList {
+              products: [Product!]!
+            }
+
+            type Product @key(fields: "id") {
+              id: ID!
+              category: Category! @shareable
+            }
+
+            type Category {
+              id: ID! @shareable
+              tag: String @shareable
+            }
+            """,
+            """
+            # name: link
+            schema {
+              query: Query
+            }
+
+            type Query {
+              productById(id: ID! @is(field: "id")): Product @lookup @internal
+            }
+
+            type Product @key(fields: "id") {
+              id: ID!
+              pid: ID! @shareable
+            }
+            """,
+            """
+            # name: price
+            schema {
+              query: Query
+            }
+
+            type Query {
+              productByIdPidAndCategory(
+                id: ID! @is(field: "id")
+                pid: ID! @is(field: "pid")
+                categoryId: ID! @is(field: "category.id")
+                categoryTag: String @is(field: "category.tag")): Product @lookup @internal
+            }
+
+            type Product @key(fields: "id pid category { id tag }") {
+              id: ID!
+              pid: ID! @shareable
+              category: Category! @shareable
+              price: Price
+            }
+
+            type Category {
+              id: ID! @shareable
+              tag: String @shareable
+            }
+
+            type Price {
+              price: Float!
+            }
+            """);
+    }
+
+    private static FusionSchemaDefinition CreateParentEntityCallComplexSchema()
+    {
+        return ComposeSchema(
+            """
+            # name: a
+            schema {
+              query: Query
+            }
+
+            type Query {
+              productById(id: ID! @is(field: "id")): Product @lookup @internal
+            }
+
+            type Product @key(fields: "id") {
+              id: ID!
+              category: Category @shareable
+            }
+
+            type Category {
+              details: String
+            }
+            """,
+            """
+            # name: b
+            schema {
+              query: Query
+            }
+
+            type Query {
+              productById(id: ID! @is(field: "id")): Product @lookup @internal
+            }
+
+            type Product @key(fields: "id") {
+              id: ID!
+              category: Category @shareable
+            }
+
+            type Category @key(fields: "id") {
+              id: ID!
+            }
+            """,
+            """
+            # name: c
+            schema {
+              query: Query
+            }
+
+            type Query {
+              categoryById(id: ID! @is(field: "id")): Category @lookup @internal
+            }
+
+            type Category @key(fields: "id") {
+              id: ID!
+              name: String
+            }
+            """,
+            """
+            # name: d
+            schema {
+              query: Query
+            }
+
+            type Query {
+              productFromD(id: ID!): Product
+              productById(id: ID! @is(field: "id")): Product @lookup @internal
+            }
+
+            type Product @key(fields: "id") {
+              id: ID!
+              name: String
+            }
+            """);
+    }
+}