diff --git a/src/type/__tests__/definition-test.js b/src/type/__tests__/definition-test.js
index ee5ca318ad..5755ead544 100644
--- a/src/type/__tests__/definition-test.js
+++ b/src/type/__tests__/definition-test.js
@@ -1198,90 +1198,3 @@ describe('Type System: NonNull must only accept non-nullable types', () => {
     });
   }
 });
-
-describe('Type System: A Schema must contain uniquely named types', () => {
-  it('rejects a Schema which redefines a built-in type', () => {
-    expect(() => {
-      const FakeString = new GraphQLScalarType({
-        name: 'String',
-        serialize: () => null,
-      });
-
-      const QueryType = new GraphQLObjectType({
-        name: 'Query',
-        fields: {
-          normal: { type: GraphQLString },
-          fake: { type: FakeString },
-        },
-      });
-
-      return new GraphQLSchema({ query: QueryType });
-    }).to.throw(
-      'Schema must contain unique named types but contains multiple types ' +
-        'named "String".',
-    );
-  });
-
-  it('rejects a Schema which defines an object type twice', () => {
-    expect(() => {
-      const A = new GraphQLObjectType({
-        name: 'SameName',
-        fields: { f: { type: GraphQLString } },
-      });
-
-      const B = new GraphQLObjectType({
-        name: 'SameName',
-        fields: { f: { type: GraphQLString } },
-      });
-
-      const QueryType = new GraphQLObjectType({
-        name: 'Query',
-        fields: {
-          a: { type: A },
-          b: { type: B },
-        },
-      });
-
-      return new GraphQLSchema({ query: QueryType });
-    }).to.throw(
-      'Schema must contain unique named types but contains multiple types ' +
-        'named "SameName".',
-    );
-  });
-
-  it('rejects a Schema which have same named objects implementing an interface', () => {
-    expect(() => {
-      const AnotherInterface = new GraphQLInterfaceType({
-        name: 'AnotherInterface',
-        fields: { f: { type: GraphQLString } },
-      });
-
-      const FirstBadObject = new GraphQLObjectType({
-        name: 'BadObject',
-        interfaces: [AnotherInterface],
-        fields: { f: { type: GraphQLString } },
-      });
-
-      const SecondBadObject = new GraphQLObjectType({
-        name: 'BadObject',
-        interfaces: [AnotherInterface],
-        fields: { f: { type: GraphQLString } },
-      });
-
-      const QueryType = new GraphQLObjectType({
-        name: 'Query',
-        fields: {
-          iface: { type: AnotherInterface },
-        },
-      });
-
-      return new GraphQLSchema({
-        query: QueryType,
-        types: [FirstBadObject, SecondBadObject],
-      });
-    }).to.throw(
-      'Schema must contain unique named types but contains multiple types ' +
-        'named "BadObject".',
-    );
-  });
-});
diff --git a/src/type/__tests__/schema-test.js b/src/type/__tests__/schema-test.js
index 5d86d8d298..124fc657d0 100644
--- a/src/type/__tests__/schema-test.js
+++ b/src/type/__tests__/schema-test.js
@@ -9,6 +9,7 @@
 
 import {
   GraphQLSchema,
+  GraphQLScalarType,
   GraphQLInterfaceType,
   GraphQLObjectType,
   GraphQLString,
@@ -109,6 +110,53 @@ describe('Type System: Schema', () => {
       });
     });
 
+    describe('A Schema must contain uniquely named types', () => {
+      it('rejects a Schema which redefines a built-in type', () => {
+        const FakeString = new GraphQLScalarType({
+          name: 'String',
+          serialize: () => null,
+        });
+
+        const QueryType = new GraphQLObjectType({
+          name: 'Query',
+          fields: {
+            normal: { type: GraphQLString },
+            fake: { type: FakeString },
+          },
+        });
+
+        expect(() => new GraphQLSchema({ query: QueryType })).to.throw(
+          'Schema must contain unique named types but contains multiple types named "String".',
+        );
+      });
+
+      it('rejects a Schema which defines an object type twice', () => {
+        const types = [
+          new GraphQLObjectType({ name: 'SameName', fields: {} }),
+          new GraphQLObjectType({ name: 'SameName', fields: {} }),
+        ];
+
+        expect(() => new GraphQLSchema({ types })).to.throw(
+          'Schema must contain unique named types but contains multiple types named "SameName".',
+        );
+      });
+
+      it('rejects a Schema which defines fields with conflicting types', () => {
+        const fields = {};
+        const QueryType = new GraphQLObjectType({
+          name: 'Query',
+          fields: {
+            a: { type: new GraphQLObjectType({ name: 'SameName', fields }) },
+            b: { type: new GraphQLObjectType({ name: 'SameName', fields }) },
+          },
+        });
+
+        expect(() => new GraphQLSchema({ query: QueryType })).to.throw(
+          'Schema must contain unique named types but contains multiple types named "SameName".',
+        );
+      });
+    });
+
     describe('when assumed valid', () => {
       it('configures the schema to have no errors', () => {
         expect(