So, with that type declaration, **FastAPI** gives you automatic request <abbr title="converting the string that comes from an HTTP request into Python data">"parsing"</abbr>.

///

## Data validation { #data-validation }

But if you go to the browser at <a href="http://127.0.0.1:8000/items/foo" class="external-link" target="_blank">http://127.0.0.1:8000/items/foo</a>, you will see a nice HTTP error of:

```JSON
{

 * governing permissions and limitations under the License.
 */
package org.codelibs.fess.app.web.admin.design;

import org.lastaflute.web.validation.Required;

/**
 * Form class for file access operations in the admin design interface.
 * This form handles file name validation for accessing design files.
 */
public class FileAccessForm {

    /** The name of the file to access (required) */
    @Required

 * governing permissions and limitations under the License.
 */
package org.codelibs.fess.app.web.admin.accesstoken;

import org.lastaflute.web.validation.Required;
import org.lastaflute.web.validation.theme.conversion.ValidateTypeFailure;

import jakarta.validation.constraints.Size;

/**
 * Form class for editing access tokens in the admin interface.

 * governing permissions and limitations under the License.
 */
package org.codelibs.fess.app.web.admin.badword;

import org.lastaflute.web.validation.Required;
import org.lastaflute.web.validation.theme.conversion.ValidateTypeFailure;

import jakarta.validation.constraints.Size;

/**
 * Form class for editing bad words in the admin interface.

 * governing permissions and limitations under the License.
 */
package org.codelibs.fess.app.web.admin.boostdoc;

import org.lastaflute.web.validation.Required;
import org.lastaflute.web.validation.theme.conversion.ValidateTypeFailure;

import jakarta.validation.constraints.Size;

/**
 * Form class for editing boost document configurations in the admin interface.

 * governing permissions and limitations under the License.
 */
package org.codelibs.fess.app.web.admin.fileauth;

import org.lastaflute.web.validation.Required;
import org.lastaflute.web.validation.theme.conversion.ValidateTypeFailure;

import jakarta.validation.constraints.Size;

/**
 * Form class for editing file authentication configurations in the admin interface.

 * governing permissions and limitations under the License.
 */
package org.codelibs.fess.app.web.admin.fileconfig;

import org.lastaflute.web.validation.Required;
import org.lastaflute.web.validation.theme.conversion.ValidateTypeFailure;

import jakarta.validation.constraints.Size;

/**
 * Form class for editing file crawling configurations in the admin interface.

 * governing permissions and limitations under the License.
 */
package org.codelibs.fess.app.web.admin.keymatch;

import org.lastaflute.web.validation.Required;
import org.lastaflute.web.validation.theme.conversion.ValidateTypeFailure;

import jakarta.validation.constraints.Size;

/**
 * Form class for editing key match configurations in the admin interface.

 * governing permissions and limitations under the License.
 */
package org.codelibs.fess.app.web.admin.webconfig;

import org.lastaflute.web.validation.Required;
import org.lastaflute.web.validation.theme.conversion.ValidateTypeFailure;

import jakarta.validation.constraints.Size;

/**
 * Form class for editing web crawling configurations in the admin interface.

    }

    @Test
    @DisplayName("Should fail validation when not received")
    void testIsValidNotReceived() {
        // When
        boolean valid = response.isValid(mockContext, mockRequest);

        // Then
        assertFalse(valid);
    }

    @Test
    @DisplayName("Should fail validation when signing enforced but not enabled")