c.Assert(err, nil)
	// verify whether complete multipart was successful.
	c.Assert(response.StatusCode, http.StatusOK)
	var parts []CompletePart
	for _, part := range completeUploads.Parts {
		part.ETag = canonicalizeETag(part.ETag)
		parts = append(parts, part)
	}
	etag := getCompleteMultipartMD5(parts)
	c.Assert(canonicalizeETag(response.Header.Get(xhttp.ETag)), etag)

		expectedErrCode  APIErrorCode
	}{
		// Test case - 1.
		// SignElement doesn't have 2 parts on an attempt to split at '='.
		// ErrMissingFields expected.
		{
			inputSignElement: "Signature",
			expectedSignStr:  "",
			expectedErrCode:  ErrMissingFields,
		},
		// Test case - 2.
		// SignElement does have 2 parts but doesn't have valid signature value.
		// ErrMissingFields expected.
		{

    if (IPV4_DELIMITER_MATCHER.countIn(ipString) + 1 != IPV4_PART_COUNT) {
      return null; // Wrong number of parts
    }

    byte[] bytes = new byte[IPV4_PART_COUNT];
    int start = 0;
    // Iterate through the parts of the ip string.
    // Invariant: start is always the beginning of an octet.
    for (int i = 0; i < IPV4_PART_COUNT; i++) {

	signature := hex.EncodeToString(sumHMAC(signingKey, []byte(stringToSign)))

	// final Authorization header
	parts := []string{
		"AWS4-HMAC-SHA256" + " Credential=" + accessKey + SlashSeparator + scope,
		"SignedHeaders=" + signedHeaders,
		"Signature=" + signature,
	}
	auth := strings.Join(parts, ", ")
	req.Header.Set("Authorization", auth)

	return signature, nil
}

// Returns new HTTP request object.

		// Failed to upload object part, abort.
		t.Fatalf("%s : %s", instanceType, err.Error())
	}

	// Complete multipart.
	parts := []CompletePart{
		{ETag: etag1, PartNumber: 1},
		{ETag: etag2, PartNumber: 2},
	}
	_, err = obj.CompleteMultipartUpload(context.Background(), bucket, object, uploadID, parts, ObjectOptions{})
	if err != nil {
		// Failed to complete multipart upload, abort.
		t.Fatalf("%s : %s", instanceType, err.Error())

...and have the code for the tests just like before.

## Testing: extended example { #testing-extended-example }

Now let's extend this example and add more details to see how to test different parts.

### Extended **FastAPI** app file { #extended-fastapi-app-file }

Let's continue with the same file structure as before:

```
.
├── app
│   ├── __init__.py
│   ├── main.py

# Simple OAuth2 with Password and Bearer { #simple-oauth2-with-password-and-bearer }

Now let's build from the previous chapter and add the missing parts to have a complete security flow.

## Get the `username` and `password` { #get-the-username-and-password }

We are going to use **FastAPI** security utilities to get the `username` and `password`.

        if (hostname != null && hostname.contains(".")) {
            // Extract potential cluster name from hostname
            String[] parts = hostname.split("\\.");
            if (parts.length > 1) {
                return parts[0]; // Use first part as cluster name
            }
        }
        return null;
    }

    /**
     * Register for witness notifications for a share

		TransitionStatus: "",
		DataDir:          "bffea160-ca7f-465f-98bc-9b4f1c3ba1ef",
		XLV1:             false,
		ModTime:          time.Now(),
		Size:             0,
		Mode:             0,
		Metadata:         nil,
		Parts:            nil,
		Erasure: ErasureInfo{
			Algorithm:    ReedSolomon.String(),
			DataBlocks:   4,
			ParityBlocks: 2,
			BlockSize:    10000,
			Index:        1,
			Distribution: []int{1, 2, 3, 4, 5, 6, 7, 8},

FastAPI stands on the shoulders of giants:

* <a href="https://www.starlette.dev/" class="external-link" target="_blank">Starlette</a> for the web parts.
* <a href="https://docs.pydantic.dev/" class="external-link" target="_blank">Pydantic</a> for the data parts.

## Installation { #installation }