WIP: Move schema validation into separate step (type constructors)

This is the second step of moving work from type constructors to the schema validation function.

src/type/__tests__/definition-test.js

@@ -270,7 +270,7 @@ describe('Type System: Example', () => {
     expect(schema.getTypeMap().NestedInputObject).to.equal(NestedInputObject);
   });
 
-  it("includes interfaces' subtypes in the type map", () => {
+  it('includes interface possible types in the type map', () => {
     const SomeInterface = new GraphQLInterfaceType({
       name: 'SomeInterface',
       fields: {
@@ -374,26 +374,13 @@ describe('Type System: Example', () => {
     });
   });
 
-  it('prohibits putting non-Object types in unions', () => {
-    const badUnionTypes = [
-      GraphQLInt,
-      GraphQLNonNull(GraphQLInt),
-      GraphQLList(GraphQLInt),
-      InterfaceType,
-      UnionType,
-      EnumType,
-      InputObjectType,
-    ];
-    badUnionTypes.forEach(x => {
-      expect(() =>
-        new GraphQLUnionType({ name: 'BadUnion', types: [x] }).getTypes(),
-      ).to.throw(
-        `BadUnion may only contain Object types, it cannot contain: ${x}.`,
-      );
-    });
+  it('prohibits nesting NonNull inside NonNull', () => {
+    expect(() => GraphQLNonNull(GraphQLNonNull(GraphQLInt))).to.throw(
+      'Expected Int! to be a GraphQL nullable type.',
+    );
   });
 
-  it("allows a thunk for Union's types", () => {
+  it('allows a thunk for Union member types', () => {
     const union = new GraphQLUnionType({
       name: 'ThunkUnion',
       types: () => [ObjectType],
@@ -470,6 +457,289 @@ describe('Type System: Example', () => {
   });
 });
 
+describe('Field config must be object', () => {
+  it('accepts an Object type with a field function', () => {
+    const objType = new GraphQLObjectType({
+      name: 'SomeObject',
+      fields() {
+        return {
+          f: { type: GraphQLString },
+        };
+      },
+    });
+    expect(objType.getFields().f.type).to.equal(GraphQLString);
+  });
+
+  it('rejects an Object type field with undefined config', () => {
+    const objType = new GraphQLObjectType({
+      name: 'SomeObject',
+      fields: {
+        f: undefined,
+      },
+    });
+    expect(() => objType.getFields()).to.throw(
+      'SomeObject.f field config must be an object',
+    );
+  });
+
+  it('rejects an Object type with incorrectly typed fields', () => {
+    const objType = new GraphQLObjectType({
+      name: 'SomeObject',
+      fields: [{ field: GraphQLString }],
+    });
+    expect(() => objType.getFields()).to.throw(
+      'SomeObject fields must be an object with field names as keys or a ' +
+        'function which returns such an object.',
+    );
+  });
+
+  it('rejects an Object type with a field function that returns incorrect type', () => {
+    const objType = new GraphQLObjectType({
+      name: 'SomeObject',
+      fields() {
+        return [{ field: GraphQLString }];
+      },
+    });
+    expect(() => objType.getFields()).to.throw(
+      'SomeObject fields must be an object with field names as keys or a ' +
+        'function which returns such an object.',
+    );
+  });
+});
+
+describe('Field arg config must be object', () => {
+  it('accepts an Object type with field args', () => {
+    const objType = new GraphQLObjectType({
+      name: 'SomeObject',
+      fields: {
+        goodField: {
+          type: GraphQLString,
+          args: {
+            goodArg: { type: GraphQLString },
+          },
+        },
+      },
+    });
+    expect(() => objType.getFields()).not.to.throw();
+  });
+
+  it('rejects an Object type with incorrectly typed field args', () => {
+    const objType = new GraphQLObjectType({
+      name: 'SomeObject',
+      fields: {
+        badField: {
+          type: GraphQLString,
+          args: [{ badArg: GraphQLString }],
+        },
+      },
+    });
+    expect(() => objType.getFields()).to.throw(
+      'SomeObject.badField args must be an object with argument names as keys.',
+    );
+  });
+});
+
+describe('Object interfaces must be array', () => {
+  it('accepts an Object type with array interfaces', () => {
+    const objType = new GraphQLObjectType({
+      name: 'SomeObject',
+      interfaces: [InterfaceType],
+      fields: { f: { type: GraphQLString } },
+    });
+    expect(objType.getInterfaces()[0]).to.equal(InterfaceType);
+  });
+
+  it('accepts an Object type with interfaces as a function returning an array', () => {
+    const objType = new GraphQLObjectType({
+      name: 'SomeObject',
+      interfaces: () => [InterfaceType],
+      fields: { f: { type: GraphQLString } },
+    });
+    expect(objType.getInterfaces()[0]).to.equal(InterfaceType);
+  });
+
+  it('rejects an Object type with incorrectly typed interfaces', () => {
+    const objType = new GraphQLObjectType({
+      name: 'SomeObject',
+      interfaces: {},
+      fields: { f: { type: GraphQLString } },
+    });
+    expect(() => objType.getInterfaces()).to.throw(
+      'SomeObject interfaces must be an Array or a function which returns an Array.',
+    );
+  });
+
+  it('rejects an Object type with interfaces as a function returning an incorrect type', () => {
+    const objType = new GraphQLObjectType({
+      name: 'SomeObject',
+      interfaces() {
+        return {};
+      },
+      fields: { f: { type: GraphQLString } },
+    });
+    expect(() => objType.getInterfaces()).to.throw(
+      'SomeObject interfaces must be an Array or a function which returns an Array.',
+    );
+  });
+});
+
+describe('Type System: Input Objects must have fields', () => {
+  it('accepts an Input Object type with fields', () => {
+    const inputObjType = new GraphQLInputObjectType({
+      name: 'SomeInputObject',
+      fields: {
+        f: { type: GraphQLString },
+      },
+    });
+    expect(inputObjType.getFields().f.type).to.equal(GraphQLString);
+  });
+
+  it('accepts an Input Object type with a field function', () => {
+    const inputObjType = new GraphQLInputObjectType({
+      name: 'SomeInputObject',
+      fields() {
+        return {
+          f: { type: GraphQLString },
+        };
+      },
+    });
+    expect(inputObjType.getFields().f.type).to.equal(GraphQLString);
+  });
+
+  it('rejects an Input Object type with incorrect fields', () => {
+    const inputObjType = new GraphQLInputObjectType({
+      name: 'SomeInputObject',
+      fields: [],
+    });
+    expect(() => inputObjType.getFields()).to.throw(
+      'SomeInputObject fields must be an object with field names as keys or a ' +
+        'function which returns such an object.',
+    );
+  });
+
+  it('rejects an Input Object type with fields function that returns incorrect type', () => {
+    const inputObjType = new GraphQLInputObjectType({
+      name: 'SomeInputObject',
+      fields() {
+        return [];
+      },
+    });
+    expect(() => inputObjType.getFields()).to.throw(
+      'SomeInputObject fields must be an object with field names as keys or a ' +
+        'function which returns such an object.',
+    );
+  });
+});
+
+describe('Type System: Input Object fields must not have resolvers', () => {
+  it('rejects an Input Object type with resolvers', () => {
+    const inputObjType = new GraphQLInputObjectType({
+      name: 'SomeInputObject',
+      fields: {
+        f: {
+          type: GraphQLString,
+          resolve: () => {
+            return 0;
+          },
+        },
+      },
+    });
+    expect(() => inputObjType.getFields()).to.throw(
+      'SomeInputObject.f field type has a resolve property, ' +
+        'but Input Types cannot define resolvers.',
+    );
+  });
+
+  it('rejects an Input Object type with resolver constant', () => {
+    const inputObjType = new GraphQLInputObjectType({
+      name: 'SomeInputObject',
+      fields: {
+        f: {
+          type: GraphQLString,
+          resolve: {},
+        },
+      },
+    });
+    expect(() => inputObjType.getFields()).to.throw(
+      'SomeInputObject.f field type has a resolve property, ' +
+        'but Input Types cannot define resolvers.',
+    );
+  });
+});
+
+describe('Type System: Enum types must be well defined', () => {
+  it('accepts a well defined Enum type with empty value definition', () => {
+    const enumType = new GraphQLEnumType({
+      name: 'SomeEnum',
+      values: {
+        FOO: {},
+        BAR: {},
+      },
+    });
+    expect(enumType.getValue('FOO').value).to.equal('FOO');
+    expect(enumType.getValue('BAR').value).to.equal('BAR');
+  });
+
+  it('accepts a well defined Enum type with internal value definition', () => {
+    const enumType = new GraphQLEnumType({
+      name: 'SomeEnum',
+      values: {
+        FOO: { value: 10 },
+        BAR: { value: 20 },
+      },
+    });
+    expect(enumType.getValue('FOO').value).to.equal(10);
+    expect(enumType.getValue('BAR').value).to.equal(20);
+  });
+
+  it('rejects an Enum type with incorrectly typed values', () => {
+    const enumType = new GraphQLEnumType({
+      name: 'SomeEnum',
+      values: [{ FOO: 10 }],
+    });
+    expect(() => enumType.getValue()).to.throw(
+      'SomeEnum values must be an object with value names as keys.',
+    );
+  });
+
+  it('rejects an Enum type with missing value definition', () => {
+    const enumType = new GraphQLEnumType({
+      name: 'SomeEnum',
+      values: { FOO: null },
+    });
+    expect(() => enumType.getValues()).to.throw(
+      'SomeEnum.FOO must refer to an object with a "value" key representing ' +
+        'an internal value but got: null.',
+    );
+  });
+
+  it('rejects an Enum type with incorrectly typed value definition', () => {
+    const enumType = new GraphQLEnumType({
+      name: 'SomeEnum',
+      values: { FOO: 10 },
+    });
+    expect(() => enumType.getValues()).to.throw(
+      'SomeEnum.FOO must refer to an object with a "value" key representing ' +
+        'an internal value but got: 10.',
+    );
+  });
+
+  it('does not allow isDeprecated without deprecationReason on enum', () => {
+    const enumType = new GraphQLEnumType({
+      name: 'SomeEnum',
+      values: {
+        FOO: {
+          isDeprecated: true,
+        },
+      },
+    });
+    expect(() => enumType.getValues()).to.throw(
+      'SomeEnum.FOO should provide "deprecationReason" instead ' +
+        'of "isDeprecated".',
+    );
+  });
+});
+
 describe('Type System: List must accept only types', () => {
   const types = [
     GraphQLString,