diff --git a/packages/middleware-retry/src/configurations.spec.ts b/packages/middleware-retry/src/configurations.spec.ts
new file mode 100644
index 000000000000..2559251b6483
--- /dev/null
+++ b/packages/middleware-retry/src/configurations.spec.ts
@@ -0,0 +1,47 @@
+import { resolveRetryConfig } from "./configurations";
+import { StandardRetryStrategy } from "./defaultStrategy";
+
+describe("resolveRetryConfig", () => {
+  describe("maxAttempts", () => {
+    it("uses passed maxAttempts value if present", () => {
+      [1, 2, 3].forEach(maxAttempts => {
+        expect(resolveRetryConfig({ maxAttempts }).maxAttempts).toEqual(
+          maxAttempts
+        );
+      });
+    });
+
+    it("assigns default value of 3 if maxAttempts not passed", () => {
+      expect(resolveRetryConfig({}).maxAttempts).toEqual(3);
+    });
+  });
+
+  describe("retryStrategy", () => {
+    it("uses passed retryStrategy if present", () => {
+      const mockRetryStrategy = {
+        maxAttempts: 2,
+        retry: jest.fn()
+      };
+      const { retryStrategy } = resolveRetryConfig({
+        retryStrategy: mockRetryStrategy
+      });
+      expect(retryStrategy).toEqual(mockRetryStrategy);
+    });
+
+    describe("creates StandardRetryStrategy if retryStrategy not present", () => {
+      describe("uses maxAttempts if present", () => {
+        [1, 2, 3].forEach(maxAttempts => {
+          const { retryStrategy } = resolveRetryConfig({ maxAttempts });
+          expect(retryStrategy).toBeInstanceOf(StandardRetryStrategy);
+          expect(retryStrategy.maxAttempts).toBe(maxAttempts);
+        });
+      });
+
+      it("uses default 3 if maxAttempts is not present", () => {
+        const { retryStrategy } = resolveRetryConfig({});
+        expect(retryStrategy).toBeInstanceOf(StandardRetryStrategy);
+        expect(retryStrategy.maxAttempts).toBe(3);
+      });
+    });
+  });
+});
diff --git a/packages/middleware-retry/src/configurations.ts b/packages/middleware-retry/src/configurations.ts
index 8a5eb0178551..a52a18b83420 100644
--- a/packages/middleware-retry/src/configurations.ts
+++ b/packages/middleware-retry/src/configurations.ts
@@ -17,13 +17,13 @@ export interface RetryResolvedConfig {
   retryStrategy: RetryStrategy;
 }
 
-export function resolveRetryConfig<T>(
+export const resolveRetryConfig = <T>(
   input: T & RetryInputConfig
-): T & RetryResolvedConfig {
-  const maxAttempts = input.maxAttempts === undefined ? 3 : input.maxAttempts;
+): T & RetryResolvedConfig => {
+  const maxAttempts = input.maxAttempts ?? 3;
   return {
     ...input,
     maxAttempts,
     retryStrategy: input.retryStrategy || new StandardRetryStrategy(maxAttempts)
   };
-}
+};
diff --git a/packages/middleware-retry/src/defaultStrategy.spec.ts b/packages/middleware-retry/src/defaultStrategy.spec.ts
new file mode 100644
index 000000000000..0b9207a34eeb
--- /dev/null
+++ b/packages/middleware-retry/src/defaultStrategy.spec.ts
@@ -0,0 +1,203 @@
+import {
+  DEFAULT_RETRY_DELAY_BASE,
+  THROTTLING_RETRY_DELAY_BASE
+} from "./constants";
+import { isThrottlingError } from "@aws-sdk/service-error-classification";
+import { defaultDelayDecider } from "./delayDecider";
+import { defaultRetryDecider } from "./retryDecider";
+import { StandardRetryStrategy } from "./defaultStrategy";
+
+jest.mock("@aws-sdk/service-error-classification", () => ({
+  isThrottlingError: jest.fn().mockReturnValue(true)
+}));
+
+jest.mock("./delayDecider", () => ({
+  defaultDelayDecider: jest.fn().mockReturnValue(0)
+}));
+
+jest.mock("./retryDecider", () => ({
+  defaultRetryDecider: jest.fn().mockReturnValue(true)
+}));
+
+describe("defaultStrategy", () => {
+  const maxAttempts = 2;
+
+  afterEach(() => {
+    jest.clearAllMocks();
+  });
+
+  it("sets maxAttempts as class member variable", () => {
+    [1, 2, 3].forEach(maxAttempts => {
+      const retryStrategy = new StandardRetryStrategy(maxAttempts);
+      expect(retryStrategy.maxAttempts).toBe(maxAttempts);
+    });
+  });
+
+  describe("retryDecider", () => {
+    it("sets defaultRetryDecider if options is undefined", () => {
+      const retryStrategy = new StandardRetryStrategy(maxAttempts);
+      expect(retryStrategy["retryDecider"]).toBe(defaultRetryDecider);
+    });
+
+    it("sets defaultRetryDecider if options.retryDecider is undefined", () => {
+      const retryStrategy = new StandardRetryStrategy(maxAttempts, {});
+      expect(retryStrategy["retryDecider"]).toBe(defaultRetryDecider);
+    });
+
+    it("sets options.retryDecider if defined", () => {
+      const retryDecider = jest.fn();
+      const retryStrategy = new StandardRetryStrategy(maxAttempts, {
+        retryDecider
+      });
+      expect(retryStrategy["retryDecider"]).toBe(retryDecider);
+    });
+  });
+
+  describe("delayDecider", () => {
+    it("sets defaultDelayDecider if options is undefined", () => {
+      const retryStrategy = new StandardRetryStrategy(maxAttempts);
+      expect(retryStrategy["delayDecider"]).toBe(defaultDelayDecider);
+    });
+
+    it("sets defaultDelayDecider if options.delayDecider undefined", () => {
+      const retryStrategy = new StandardRetryStrategy(maxAttempts, {});
+      expect(retryStrategy["delayDecider"]).toBe(defaultDelayDecider);
+    });
+
+    it("sets options.delayDecider if defined", () => {
+      const delayDecider = jest.fn();
+      const retryStrategy = new StandardRetryStrategy(maxAttempts, {
+        delayDecider
+      });
+      expect(retryStrategy["delayDecider"]).toBe(delayDecider);
+    });
+  });
+
+  describe("delayBase passed to delayDecider", () => {
+    const testDelayBasePassed = async (
+      delayBaseToTest: number,
+      mockThrottlingError: boolean
+    ) => {
+      (isThrottlingError as jest.Mock).mockReturnValueOnce(mockThrottlingError);
+
+      const mockError = new Error("mockError");
+      const mockResponse = {
+        response: "mockResponse",
+        output: { $metadata: {} }
+      };
+
+      const next = jest
+        .fn()
+        .mockRejectedValueOnce(mockError)
+        .mockResolvedValueOnce(mockResponse);
+
+      const retryStrategy = new StandardRetryStrategy(maxAttempts);
+      await retryStrategy.retry(next, {} as any);
+
+      expect(isThrottlingError as jest.Mock).toHaveBeenCalledTimes(1);
+      expect(isThrottlingError as jest.Mock).toHaveBeenCalledWith(mockError);
+      expect(defaultDelayDecider as jest.Mock).toHaveBeenCalledTimes(1);
+      expect(defaultDelayDecider as jest.Mock).toHaveBeenCalledWith(
+        delayBaseToTest,
+        1
+      );
+    };
+
+    it("should be equal to THROTTLING_RETRY_DELAY_BASE if error is throttling error", async () => {
+      return testDelayBasePassed(THROTTLING_RETRY_DELAY_BASE, true);
+    });
+
+    it("should be equal to DEFAULT_RETRY_DELAY_BASE in error is not a throttling error", async () => {
+      return testDelayBasePassed(DEFAULT_RETRY_DELAY_BASE, false);
+    });
+  });
+
+  describe("should not retry", () => {
+    it("when the handler completes successfully", async () => {
+      const mockResponse = {
+        response: "mockResponse",
+        output: { $metadata: {} }
+      };
+
+      const next = jest.fn().mockResolvedValueOnce(mockResponse);
+
+      const retryStrategy = new StandardRetryStrategy(maxAttempts);
+      const { response, output } = await retryStrategy.retry(next, {} as any);
+
+      expect(response).toStrictEqual(mockResponse.response);
+      expect(output.$metadata.attempts).toBe(1);
+      expect(output.$metadata.totalRetryDelay).toBe(0);
+      expect(defaultRetryDecider as jest.Mock).not.toHaveBeenCalled();
+      expect(defaultDelayDecider as jest.Mock).not.toHaveBeenCalled();
+    });
+
+    it("when retryDecider returns false", async () => {
+      (defaultRetryDecider as jest.Mock).mockReturnValueOnce(false);
+
+      const mockError = new Error("mockError");
+      const next = jest.fn().mockRejectedValueOnce(mockError);
+
+      const retryStrategy = new StandardRetryStrategy(maxAttempts);
+      try {
+        await retryStrategy.retry(next, {} as any);
+      } catch (error) {
+        expect(error).toStrictEqual(mockError);
+      }
+
+      expect(defaultRetryDecider as jest.Mock).toHaveBeenCalledTimes(1);
+      expect(defaultRetryDecider as jest.Mock).toHaveBeenCalledWith(mockError);
+    });
+
+    it("when the the maximum number of attempts is reached", async () => {
+      const mockError = new Error("mockError");
+      const next = jest.fn().mockRejectedValue(mockError);
+
+      const retryStrategy = new StandardRetryStrategy(maxAttempts);
+      try {
+        await retryStrategy.retry(next, {} as any);
+      } catch (error) {
+        expect(error).toStrictEqual(mockError);
+      }
+      expect(defaultRetryDecider as jest.Mock).toHaveBeenCalledTimes(
+        maxAttempts - 1
+      );
+    });
+  });
+
+  it("should delay equal to the value returned by delayDecider", async () => {
+    jest.spyOn(global, "setTimeout");
+
+    const FIRST_DELAY = 100;
+    const SECOND_DELAY = 200;
+
+    (defaultDelayDecider as jest.Mock)
+      .mockReturnValueOnce(FIRST_DELAY)
+      .mockReturnValueOnce(SECOND_DELAY);
+
+    const mockError = new Error("mockError");
+    const next = jest.fn().mockRejectedValue(mockError);
+
+    const retryStrategy = new StandardRetryStrategy(3);
+    try {
+      await retryStrategy.retry(next, {} as any);
+    } catch (error) {
+      expect(error).toStrictEqual(mockError);
+      expect(error.$metadata.totalRetryDelay).toEqual(
+        FIRST_DELAY + SECOND_DELAY
+      );
+    }
+
+    expect(defaultDelayDecider as jest.Mock).toHaveBeenCalledTimes(2);
+    expect(setTimeout).toHaveBeenCalledTimes(2);
+    expect(setTimeout).toHaveBeenNthCalledWith(
+      1,
+      expect.any(Function),
+      FIRST_DELAY
+    );
+    expect(setTimeout).toHaveBeenNthCalledWith(
+      2,
+      expect.any(Function),
+      SECOND_DELAY
+    );
+  });
+});
diff --git a/packages/middleware-retry/src/index.spec.ts b/packages/middleware-retry/src/index.spec.ts
deleted file mode 100644
index 3c1f972b120a..000000000000
--- a/packages/middleware-retry/src/index.spec.ts
+++ /dev/null
@@ -1,92 +0,0 @@
-import {
-  DEFAULT_RETRY_DELAY_BASE,
-  THROTTLING_RETRY_DELAY_BASE
-} from "./constants";
-import { retryMiddleware } from "./retryMiddleware";
-import { resolveRetryConfig } from "./configurations";
-import * as delayDeciderModule from "./delayDecider";
-import { StandardRetryStrategy, RetryDecider } from "./defaultStrategy";
-import { HttpRequest } from "@aws-sdk/protocol-http";
-import { SdkError } from "@aws-sdk/smithy-client";
-
-describe("retryMiddleware", () => {
-  it("should not retry when the handler completes successfully", async () => {
-    const next = jest.fn().mockResolvedValue({ output: { $metadata: {} } });
-    const retryHandler = retryMiddleware(
-      resolveRetryConfig({ maxAttempts: 0 })
-    )(next);
-
-    const {
-      output: { $metadata }
-    } = await retryHandler({ input: {}, request: new HttpRequest({}) });
-    expect($metadata.attempts).toBe(1);
-    expect($metadata.totalRetryDelay).toBe(0);
-
-    expect(next.mock.calls.length).toBe(1);
-  });
-
-  it("should stop retrying when the the maximum number of retries is reached", async () => {
-    const maxAttempts = 3;
-    const error = new Error();
-    error.name = "ProvisionedThroughputExceededException";
-    const next = jest.fn().mockRejectedValue(error);
-    const retryHandler = retryMiddleware(resolveRetryConfig({ maxAttempts }))(
-      next
-    );
-
-    await expect(
-      retryHandler({ input: {}, request: new HttpRequest({}) })
-    ).rejects.toMatchObject(error);
-
-    expect(next.mock.calls.length).toBe(maxAttempts);
-  });
-
-  it("should not retry if the error is not transient", async () => {
-    const error = new Error();
-    error.name = "ValidationException";
-    const next = jest.fn().mockRejectedValue(error);
-    const retryHandler = retryMiddleware(
-      resolveRetryConfig({ maxAttempts: 3 })
-    )(next);
-
-    await expect(
-      retryHandler({ input: {}, request: new HttpRequest({}) })
-    ).rejects.toMatchObject(error);
-
-    expect(next.mock.calls.length).toBe(1);
-  });
-
-  it("should use a higher base delay when a throttling error is encountered", async () => {
-    const next = jest.fn().mockResolvedValue({ output: { $metadata: {} } });
-
-    const validation = new Error();
-    validation.name = "ValidationException";
-    next.mockImplementationOnce(args => Promise.reject(validation));
-
-    const throttling = new Error();
-    throttling.name = "RequestLimitExceeded";
-    next.mockImplementationOnce(args => Promise.reject(throttling));
-
-    jest.mock("./delayDecider");
-
-    const maxAttempts = 3;
-    const delayDeciderMock = jest.spyOn(
-      delayDeciderModule,
-      "defaultDelayDecider"
-    );
-    const retryDecider: RetryDecider = (error: SdkError) => true;
-    const strategy = new StandardRetryStrategy(maxAttempts, { retryDecider });
-    const retryHandler = retryMiddleware({
-      maxAttempts,
-      retryStrategy: strategy
-    })(next);
-
-    await retryHandler({ input: {}, request: new HttpRequest({}) });
-
-    expect(next.mock.calls.length).toBe(3);
-    expect(delayDeciderMock.mock.calls).toEqual([
-      [DEFAULT_RETRY_DELAY_BASE, 1],
-      [THROTTLING_RETRY_DELAY_BASE, 2]
-    ]);
-  });
-});
diff --git a/packages/middleware-retry/src/retryDecider.spec.ts b/packages/middleware-retry/src/retryDecider.spec.ts
index 15ed0732cfee..271f22baba0b 100644
--- a/packages/middleware-retry/src/retryDecider.spec.ts
+++ b/packages/middleware-retry/src/retryDecider.spec.ts
@@ -24,53 +24,53 @@ describe("defaultRetryDecider", () => {
 
   it("should return false when the provided error is falsy", () => {
     expect(defaultRetryDecider(null as any)).toBe(false);
-    expect((isRetryableByTrait as jest.Mock).mock.calls.length).toBe(0);
-    expect((isClockSkewError as jest.Mock).mock.calls.length).toBe(0);
-    expect((isThrottlingError as jest.Mock).mock.calls.length).toBe(0);
-    expect((isTransientError as jest.Mock).mock.calls.length).toBe(0);
+    expect(isRetryableByTrait as jest.Mock).toHaveBeenCalledTimes(0);
+    expect(isClockSkewError as jest.Mock).toHaveBeenCalledTimes(0);
+    expect(isThrottlingError as jest.Mock).toHaveBeenCalledTimes(0);
+    expect(isTransientError as jest.Mock).toHaveBeenCalledTimes(0);
   });
 
   it("should return true for RetryableByTrait error", () => {
     (isRetryableByTrait as jest.Mock).mockReturnValueOnce(true);
     expect(defaultRetryDecider(createMockError())).toBe(true);
-    expect((isRetryableByTrait as jest.Mock).mock.calls.length).toBe(1);
-    expect((isClockSkewError as jest.Mock).mock.calls.length).toBe(0);
-    expect((isThrottlingError as jest.Mock).mock.calls.length).toBe(0);
-    expect((isTransientError as jest.Mock).mock.calls.length).toBe(0);
+    expect(isRetryableByTrait as jest.Mock).toHaveBeenCalledTimes(1);
+    expect(isClockSkewError as jest.Mock).toHaveBeenCalledTimes(0);
+    expect(isThrottlingError as jest.Mock).toHaveBeenCalledTimes(0);
+    expect(isTransientError as jest.Mock).toHaveBeenCalledTimes(0);
   });
 
   it("should return true for ClockSkewError", () => {
     (isClockSkewError as jest.Mock).mockReturnValueOnce(true);
     expect(defaultRetryDecider(createMockError())).toBe(true);
-    expect((isRetryableByTrait as jest.Mock).mock.calls.length).toBe(1);
-    expect((isClockSkewError as jest.Mock).mock.calls.length).toBe(1);
-    expect((isThrottlingError as jest.Mock).mock.calls.length).toBe(0);
-    expect((isTransientError as jest.Mock).mock.calls.length).toBe(0);
+    expect(isRetryableByTrait as jest.Mock).toHaveBeenCalledTimes(1);
+    expect(isClockSkewError as jest.Mock).toHaveBeenCalledTimes(1);
+    expect(isThrottlingError as jest.Mock).toHaveBeenCalledTimes(0);
+    expect(isTransientError as jest.Mock).toHaveBeenCalledTimes(0);
   });
 
   it("should return true for ThrottlingError", () => {
     (isThrottlingError as jest.Mock).mockReturnValueOnce(true);
     expect(defaultRetryDecider(createMockError())).toBe(true);
-    expect((isRetryableByTrait as jest.Mock).mock.calls.length).toBe(1);
-    expect((isClockSkewError as jest.Mock).mock.calls.length).toBe(1);
-    expect((isThrottlingError as jest.Mock).mock.calls.length).toBe(1);
-    expect((isTransientError as jest.Mock).mock.calls.length).toBe(0);
+    expect(isRetryableByTrait as jest.Mock).toHaveBeenCalledTimes(1);
+    expect(isClockSkewError as jest.Mock).toHaveBeenCalledTimes(1);
+    expect(isThrottlingError as jest.Mock).toHaveBeenCalledTimes(1);
+    expect(isTransientError as jest.Mock).toHaveBeenCalledTimes(0);
   });
 
   it("should return true for TransientError", () => {
     (isTransientError as jest.Mock).mockReturnValueOnce(true);
     expect(defaultRetryDecider(createMockError())).toBe(true);
-    expect((isRetryableByTrait as jest.Mock).mock.calls.length).toBe(1);
-    expect((isClockSkewError as jest.Mock).mock.calls.length).toBe(1);
-    expect((isThrottlingError as jest.Mock).mock.calls.length).toBe(1);
-    expect((isTransientError as jest.Mock).mock.calls.length).toBe(1);
+    expect(isRetryableByTrait as jest.Mock).toHaveBeenCalledTimes(1);
+    expect(isClockSkewError as jest.Mock).toHaveBeenCalledTimes(1);
+    expect(isThrottlingError as jest.Mock).toHaveBeenCalledTimes(1);
+    expect(isTransientError as jest.Mock).toHaveBeenCalledTimes(1);
   });
 
   it("should return false for other errors", () => {
     expect(defaultRetryDecider(createMockError())).toBe(false);
-    expect((isRetryableByTrait as jest.Mock).mock.calls.length).toBe(1);
-    expect((isClockSkewError as jest.Mock).mock.calls.length).toBe(1);
-    expect((isThrottlingError as jest.Mock).mock.calls.length).toBe(1);
-    expect((isTransientError as jest.Mock).mock.calls.length).toBe(1);
+    expect(isRetryableByTrait as jest.Mock).toHaveBeenCalledTimes(1);
+    expect(isClockSkewError as jest.Mock).toHaveBeenCalledTimes(1);
+    expect(isThrottlingError as jest.Mock).toHaveBeenCalledTimes(1);
+    expect(isTransientError as jest.Mock).toHaveBeenCalledTimes(1);
   });
 });
diff --git a/packages/middleware-retry/src/retryMiddleware.spec.ts b/packages/middleware-retry/src/retryMiddleware.spec.ts
new file mode 100644
index 000000000000..08a49b3708e5
--- /dev/null
+++ b/packages/middleware-retry/src/retryMiddleware.spec.ts
@@ -0,0 +1,76 @@
+import {
+  getRetryPlugin,
+  retryMiddleware,
+  retryMiddlewareOptions
+} from "./retryMiddleware";
+import {
+  MiddlewareStack,
+  RetryStrategy,
+  FinalizeHandlerArguments
+} from "@aws-sdk/types";
+
+describe("getRetryPlugin", () => {
+  const mockClientStack = {
+    add: jest.fn()
+  };
+
+  afterEach(() => {
+    jest.clearAllMocks();
+  });
+
+  describe("adds retryMiddleware if maxAttempts > 1", () => {
+    [2, 3, 4].forEach(maxAttempts => {
+      it(`when maxAttempts=${maxAttempts}`, () => {
+        getRetryPlugin({
+          maxAttempts,
+          retryStrategy: {} as RetryStrategy
+        }).applyToStack(
+          (mockClientStack as unknown) as MiddlewareStack<any, any>
+        );
+        expect(mockClientStack.add).toHaveBeenCalledTimes(1);
+        expect(mockClientStack.add.mock.calls[0][1]).toEqual(
+          retryMiddlewareOptions
+        );
+      });
+    });
+  });
+
+  describe("skips adding retryMiddleware if maxAttempts <= 1", () => {
+    [0, 1].forEach(maxAttempts => {
+      it(`when maxAttempts=${maxAttempts}`, () => {
+        getRetryPlugin({
+          maxAttempts,
+          retryStrategy: {} as RetryStrategy
+        }).applyToStack(
+          (mockClientStack as unknown) as MiddlewareStack<any, any>
+        );
+        expect(mockClientStack.add).toHaveBeenCalledTimes(0);
+      });
+    });
+  });
+});
+
+describe("retryMiddleware", () => {
+  afterEach(() => {
+    jest.clearAllMocks();
+  });
+
+  it("calls retryStrategy.retry with next and args", async () => {
+    const maxAttempts = 2;
+    const next = jest.fn();
+    const args = {
+      request: {}
+    };
+    const mockRetryStrategy = {
+      maxAttempts,
+      retry: jest.fn()
+    };
+
+    await retryMiddleware({
+      maxAttempts,
+      retryStrategy: mockRetryStrategy
+    })(next)(args as FinalizeHandlerArguments<any>);
+    expect(mockRetryStrategy.retry).toHaveBeenCalledTimes(1);
+    expect(mockRetryStrategy.retry).toHaveBeenCalledWith(next, args);
+  });
+});
diff --git a/packages/middleware-retry/src/retryMiddleware.ts b/packages/middleware-retry/src/retryMiddleware.ts
index 2bc454e80506..bbd72ec957f4 100644
--- a/packages/middleware-retry/src/retryMiddleware.ts
+++ b/packages/middleware-retry/src/retryMiddleware.ts
@@ -9,15 +9,14 @@ import {
 } from "@aws-sdk/types";
 import { RetryResolvedConfig } from "./configurations";
 
-export function retryMiddleware(options: RetryResolvedConfig) {
-  return <Output extends MetadataBearer = MetadataBearer>(
-    next: FinalizeHandler<any, Output>
-  ): FinalizeHandler<any, Output> => async (
-    args: FinalizeHandlerArguments<any>
-  ): Promise<FinalizeHandlerOutput<Output>> => {
-    return options.retryStrategy.retry(next, args);
-  };
-}
+export const retryMiddleware = (options: RetryResolvedConfig) => <
+  Output extends MetadataBearer = MetadataBearer
+>(
+  next: FinalizeHandler<any, Output>
+): FinalizeHandler<any, Output> => async (
+  args: FinalizeHandlerArguments<any>
+): Promise<FinalizeHandlerOutput<Output>> =>
+  options.retryStrategy.retry(next, args);
 
 export const retryMiddlewareOptions: FinalizeRequestHandlerOptions &
   AbsoluteLocation = {