Instead, you want to provide a different dependency that will be used only during tests (possibly only some specific tests), and will provide a value that can be used where the value of the original dependency was used.

### Use cases: external service { #use-cases-external-service }

An example could be that you have an external authentication provider that you need to call.

You send it a token and it returns an authenticated user.

///

## Use cases { #use-cases }

Some use cases include:

* Converting non-JSON request bodies to JSON (e.g. <a href="https://msgpack.org/index.html" class="external-link" target="_blank">`msgpack`</a>).
* Decompressing gzip-compressed request bodies.
* Automatically logging all request bodies.

## Handling custom request body encodings { #handling-custom-request-body-encodings }

	"github.com/google/uuid"
)

var testUUID = uuid.MustParse("f5c58c61-7175-4018-ab5e-a94fe9c2de4e")

func BenchmarkCrcHash(b *testing.B) {
	cases := []struct {
		key int
	}{
		{16},
		{64},
		{128},
		{256},
		{512},
		{1024},
	}
	for _, testCase := range cases {
		key := randString(testCase.key)
		b.Run("", func(b *testing.B) {
			b.SetBytes(1024)
			b.ReportAllocs()
			b.ResetTimer()
			for b.Loop() {

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package cmd

import (
	"testing"
)

func TestSplitPath(t *testing.T) {
	cases := []struct {
		path                          string
		secondIndex                   bool
		expectedListKey, expectedItem string
	}{
		{"format.json", false, "format.json", ""},

But in those cases with really bad errors that crash the running **process**, you would want an external component that is in charge of **restarting** the process, at least a couple of times...

/// tip

				return
			}
		}
	}

	for idx, ownField := range ownForeignFields {
		joinFieldName := cases.Title(language.Und, cases.NoLower).String(schema.Name) + ownField.Name
		if len(joinForeignKeys) > idx {
			joinFieldName = cases.Title(language.Und, cases.NoLower).String(joinForeignKeys[idx])
		}

		ownFieldsMap[joinFieldName] = ownField
		fieldsMap[joinFieldName] = ownField

# Response - Change Status Code { #response-change-status-code }

You probably read before that you can set a default [Response Status Code](../tutorial/response-status-code.md){.internal-link target=_blank}.

But in some cases you need to return a different status code than the default.

## Use case { #use-case }

For example, imagine that you want to return an HTTP status code of "OK" `200` by default.

# Dependencies in path operation decorators { #dependencies-in-path-operation-decorators }

In some cases you don't really need the return value of a dependency inside your *path operation function*.

Or the dependency doesn't return a value.

But you still need it to be executed/solved.

For those cases, instead of declaring a *path operation function* parameter with `Depends`, you can add a `list` of `dependencies` to the *path operation decorator*.

	}

	// Validate all the test cases.
	for i, testCase := range testCases {
		actualInfo, actualErr := obj.PutObjectPart(context.Background(), testCase.bucketName, testCase.objName, testCase.uploadID, testCase.PartID, mustGetPutObjReader(t, bytes.NewBufferString(testCase.inputReaderData), testCase.inputDataSize, testCase.inputMd5, testCase.inputSHA256), opts)
		// All are test cases above are expected to fail.

   * the discussion in the {@link #addListener} documentation. All its warnings about heavyweight
   * listeners are also applicable to heavyweight functions passed to this method.
   *
   * <p>This method is similar to {@link java.util.concurrent.CompletableFuture#exceptionally}. It
   * can also serve some of the use cases of {@link java.util.concurrent.CompletableFuture#handle}