# Async Tests { #async-tests }

You have already seen how to test your **FastAPI** applications using the provided `TestClient`. Up to now, you have only seen how to write synchronous tests, without using `async` functions.

Klaus Post <******@****.***> 1756435188 +0200

///

/// tip

If you want to call `async` functions in your tests apart from sending requests to your FastAPI application (e.g. asynchronous database functions), have a look at the [Async Tests](../advanced/async-tests.md){.internal-link target=_blank} in the advanced tutorial.

///

## Separating tests { #separating-tests }

In a real application, you probably would have your tests in a different file.

		{"00000000000000001", 0, "http chunk length too large"}, // could accept if we wanted
	}
	for i := uint64(0); i <= 1234; i++ {
		tests = append(tests, testCase{in: fmt.Sprintf("%x", i), want: i})
	}
	for _, tt := range tests {
		got, err := parseHexUint([]byte(tt.in))
		if tt.wantErr != "" {
			if err != nil && !strings.Contains(err.Error(), tt.wantErr) {

You don't want the original dependency to run (nor any of the sub-dependencies it might have).

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 }

// This makes it easy to run the TestServer from any of the tests.
// Using this interface, functionalities to be used in tests can be
// made generalized, and can be integrated in benchmarks/unit tests/go check suite tests.
type TestErrHandler interface {
	testing.TB
}

const (
	// ErasureSDStr is the string which is used as notation for Single node ObjectLayer in the unit tests.
	ErasureSDStr string = "ErasureSD"

      <artifactId>guava-testlib</artifactId>
      <version>${project.version}</version>
      <classifier>tests</classifier>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>com.google.guava</groupId>
      <artifactId>guava-tests</artifactId>
      <version>${project.version}</version>
      <classifier>tests</classifier>
      <scope>test</scope>
    </dependency>
    <dependency>

mvn license:format

# Run static analysis
mvn spotbugs:check
```

### Running Tests

```bash
# Run all tests
mvn test

# Run specific test class
mvn test -Dtest=CrawlerTest

# Run specific test method
mvn test -Dtest=CrawlerTest#test_execute_web

# Run tests for specific module
mvn test -pl fess-crawler
```

## Examples

### Web Crawling with Custom Rules

			seq = append(seq, fmt.Sprintf(fmt.Sprintf("%%0%dd", paddinglen), i))
		}
	}
	return seq
}

// Test tests parses endpoint ellipses input pattern.
func TestParseEndpointSet(t *testing.T) {
	testCases := []struct {
		arg     string
		es      endpointSet
		success bool
	}{
		// Tests invalid inputs.
		{
			"...",
			endpointSet{},
			false,
		},
		// No range specified.
		{

You should add tests for your app.

With **FastAPI** it's very easy (thanks to Starlette), check the docs: [Testing](../tutorial/testing.md){.internal-link target=_blank}

After you have tests, then you can upgrade the **FastAPI** version to a more recent one, and make sure that all your code is working correctly by running your tests.