diff --git a/README.md b/README.md
index f0c929e..fb59257 100644
--- a/README.md
+++ b/README.md
@@ -47,6 +47,11 @@
 - [Getting Started](#getting-started)
   - [Installation](#installation)
   - [Usage](#usage)
+    - [Default Case](#default-case)
+    - [Partial Nested Shape](#partial-nested-shape)
+    - [Providing Functions as Resolver](#providing-functions-as-resolver)
+    - [Mocking Errors](#mocking-errors)
+    - [Mocking Mutations](#mocking-mutations)
 - [Roadmap](#roadmap)
 - [Contributing](#contributing)
 - [License](#license)
@@ -145,8 +150,41 @@ npm i graphql-ergonomock --save-dev
 <!-- USAGE EXAMPLES -->
 ### Usage
 
+#### Default Case
+
 TBD
 
+#### Partial Nested Shape
+
+TBD
+
+#### Providing Functions as Resolver
+
+TBD
+
+#### Mocking Errors
+
+```js
+const testQuery = gql`
+  {
+    getCar {
+      id
+    }
+  }
+`;
+
+const resp = mock(schema, testQuery, {
+  getCar: () => { throw new Error("Server Error"); }
+  // or simply getCar: new Error("Server Error")
+});
+
+console.log(resp.data.getCar); // null
+console.log(resp.errors[0]); // { message: "Server Error", ...}
+```
+
+#### Mocking Mutations
+
+TBD
 
 <!-- ROADMAP -->
 ## Roadmap
diff --git a/src/__tests__/lib.test.ts b/src/__tests__/lib.test.ts
index 6d8c363..a65c0eb 100644
--- a/src/__tests__/lib.test.ts
+++ b/src/__tests__/lib.test.ts
@@ -1,6 +1,6 @@
 import { mock } from "..";
 import { buildSchemaFromTypeDefinitions } from "graphql-tools";
-import { visitWithTypeInfo } from "graphql";
+import { visitWithTypeInfo, GraphQLError } from "graphql";
 // import { graphql, GraphQLResolveInfo } from "graphql";
 
 const schemaSDL = /* GraphQL */ `
@@ -914,13 +914,142 @@ describe("Automocking", () => {
   });
 
   describe("mocking errors", () => {
-    test.todo("can provide Errors for basic types");
-    test.todo("can provide Errors for enums");
-    test.todo("can provide Errors for objects");
-    test.todo("can provide Errors for lists (one error among list items)");
-    test.todo("can provide Errors for unions");
-    test.todo("can provide Errors for interfaces");
-    test.todo("can throw errors in functions as resolver");
+    test("can provide Errors for basic types", () => {
+      const testQuery = /* GraphQL */ `
+        {
+          returnInt
+          returnString
+        }
+      `;
+      const resp: any = mock(schema, testQuery, {
+        returnInt: new Error("foo bar")
+      });
+      expect(resp.data).toMatchObject({
+        returnInt: null,
+        returnString: expect.toBeString()
+      });
+      expect(resp.errors).toStrictEqual([new GraphQLError("foo bar")]);
+    });
+
+    test("can provide Errors for enums", () => {
+      const testQuery = /* GraphQL */ `
+        {
+          returnEnum
+          returnString
+        }
+      `;
+      const resp: any = mock(schema, testQuery, {
+        returnEnum: new Error("foo enum")
+      });
+      expect(resp.data).toMatchObject({
+        returnEnum: null,
+        returnString: expect.toBeString()
+      });
+      expect(resp.errors).toStrictEqual([new GraphQLError("foo enum")]);
+    });
+
+    test("can provide Errors for objects", () => {
+      const testQuery = /* GraphQL */ `
+        {
+          returnShape {
+            id
+          }
+          returnString
+        }
+      `;
+      const resp: any = mock(schema, testQuery, {
+        returnShape: new Error("foo shape")
+      });
+      expect(resp.data).toMatchObject({
+        returnShape: null,
+        returnString: expect.toBeString()
+      });
+      expect(resp.errors).toStrictEqual([new GraphQLError("foo shape")]);
+    });
+
+    test("can provide Errors for lists (one error among list items)", () => {
+      const testQuery = /* GraphQL */ `
+        {
+          returnStringList
+          returnString
+        }
+      `;
+      const resp: any = mock(schema, testQuery, {
+        returnStringList: ["Whiskey", new Error("foo Tango"), "Foxtrot"]
+      });
+      expect(resp.data).toMatchObject({
+        returnStringList: ["Whiskey", null, "Foxtrot"],
+        returnString: expect.toBeString()
+      });
+      expect(resp.errors).toStrictEqual([new GraphQLError("foo Tango")]);
+    });
+
+    test("can provide Errors for unions", () => {
+      const testQuery = /* GraphQL */ `
+        {
+          returnBirdsAndBees {
+            __typename
+            id
+          }
+          returnString
+        }
+      `;
+      const resp: any = mock(schema, testQuery, {
+        returnBirdsAndBees: [{ __typename: "Bird" }, new Error("foo Tango"), { __typename: "Bee" }]
+      });
+      expect(resp.data).toMatchObject({
+        returnBirdsAndBees: [
+          { __typename: "Bird", id: expect.toBeString() },
+          null,
+          { __typename: "Bee", id: expect.toBeString() }
+        ],
+        returnString: expect.toBeString()
+      });
+      expect(resp.errors).toStrictEqual([new GraphQLError("foo Tango")]);
+    });
+    test("can provide Errors for interfaces", () => {
+      const testQuery = /* GraphQL */ `
+        {
+          returnFlying {
+            __typename
+            id
+          }
+          returnString
+        }
+      `;
+      const resp: any = mock(schema, testQuery, {
+        returnFlying: [{ __typename: "Bird" }, new Error("foo Tango"), { __typename: "Bee" }]
+      });
+      expect(resp.data).toMatchObject({
+        returnFlying: [
+          { __typename: "Bird", id: expect.toBeString() },
+          null,
+          { __typename: "Bee", id: expect.toBeString() }
+        ],
+        returnString: expect.toBeString()
+      });
+      expect(resp.errors).toStrictEqual([new GraphQLError("foo Tango")]);
+    });
+    test("can throw errors in functions as resolver", () => {
+      const testQuery = /* GraphQL */ `
+        {
+          returnShape {
+            id
+          }
+          returnString
+        }
+      `;
+      const resp: any = mock(schema, testQuery, {
+        returnShape: () => {
+          throw new Error("foo shape");
+        }
+      });
+      expect(resp.data).toMatchObject({
+        returnShape: null,
+        returnString: expect.toBeString()
+      });
+      expect(resp.errors).toStrictEqual([new GraphQLError("foo shape")]);
+    });
   });
 
   test("base case - TBD remove this test later", () => {