hash.Write(msg)
			sum = hash.Sum(sum[:0])
			msg = append(msg, sum...)
			hash.Reset()
		}
		if !bytes.Equal(sum, checksum) {
			logger.Fatal(errSelfTestFailure, fmt.Sprintf("bitrot: %v selftest checksum mismatch: got %x - want %x", algorithm, sum, checksum))
		}
	}

func validateCredentialfields(t *testing.T, testNum int, expectedCredentials credentialHeader, actualCredential credentialHeader) {
	if expectedCredentials.accessKey != actualCredential.accessKey {
		t.Errorf("Test %d: AccessKey mismatch: Expected \"%s\", got \"%s\"", testNum, expectedCredentials.accessKey, actualCredential.accessKey)
	}
	if !expectedCredentials.scope.date.Equal(actualCredential.scope.date) {

		}
		got := uint32(xxh3.Hash(b[:len(b)-hashLen]))
		want := binary.LittleEndian.Uint32(h[len(h)-hashLen:])
		if got != want {
			return nil, nil, fmt.Errorf("crc mismatch: 0x%08x (given) != 0x%08x (bytes)", want, got)
		}
		h = h[:len(h)-hashLen]
	}
	// Extract subroute if any.
	if m.Flags&FlagSubroute != 0 {
		if len(h) < 32 {

    lock.assertHeld()

    val routeUrl = route.address.url

    if (url.port != routeUrl.port) {
      return false // Port mismatch.
    }

    if (url.host == routeUrl.host) {
      return true // Host match. The URL is supported.
    }

    // We have a host mismatch. But if the certificate matches, we're still good.
    return !noCoalescedConnections && handshake != null && certificateSupportHost(url, handshake!!)

        // == sanity check
        if (result.size() != org.apache.maven.api.DependencyScope.values().length - 1) { // sans "undefined"
            throw new IllegalStateException("Maven4 API dependency scope mismatch");
        }

        return result;
    }

    @Override
    public Collection<org.eclipse.aether.scope.ResolutionScope> buildResolutionScopes(
            InternalScopeManager internalScopeManager) {

		if _, err := io.Copy(io.Discard, reader); err != nil {
			t.Fatalf("Test %d: read failed: %v", i, err)
		}
		if ETag := reader.ETag(); !Equal(ETag, test.ETag) {
			t.Fatalf("Test %d: ETag mismatch: got %q - want %q", i, ETag, test.ETag)
		}
	}
}

var multipartTests = []struct { // Test cases have been generated using AWS S3
	ETags     []ETag
	Multipart ETag
}{
	{
		ETags:     []ETag{},

         * in such a way that there can be a slash at the end of the path. This
         * causes problems matching keys in resolve() where an extra slash causes
         * a mismatch. This strips trailing slashes from all keys to eliminate
         * this problem.
         */
        int ki = key.length();
        while (ki > 1 && key.charAt(ki - 1) == '\\') {
            ki--;
        }

	sobj.Close()
	tobj.Close()

	if !sourceFailed && !targetFailed {
		ssum := srcSha256.Sum(nil)
		tsum := tgtSha256.Sum(nil)
		allgood = bytes.Equal(ssum, tsum)
		if !allgood {
			fmt.Printf("sha256 sum mismatch: %s -> Expected(%x), Found(%x)\n", srcCtnt.Key, ssum, tsum)
		}
	}

	return allgood

This also means that if something changed it will be **reflected** on the client code automatically. And if you **build** the client it will error out if you have any **mismatch** in the data used.

			accessKey:          credentials.AccessKey,
			secretKey:          credentials.SecretKey,
			expectedRespStatus: http.StatusNotFound,
		},
		// Test case - 3.
		// Test case to induce a signature mismatch.
		// Using invalid accessID.
		{
			bucketName:         bucketName,
			objectName:         objectName,
			accessKey:          "Invalid-AccessID",
			secretKey:          credentials.SecretKey,