[BUG] no test code generated for Java

[grexe]

Description

Despite correct options and reading the docs, no test sources are generated for valid yaml with the Java spring/spring-boot generator.

openapi-generator version

openapi-generator(-maven-plugin) 4.3.1

OpenAPI declaration file content or url

cannot post without confirmation from company, but models are generated just fine, only tests are missing.

Command line used for generation

Using Maven 3.6.1, AdoptOpenJDK 11.0.4 and version above.

Steps to reproduce

options used:

<configuration>
    <inputSpec>${project.basedir}/src/main/resources/openapi/my-api.yml</inputSpec>
    <generatorName>spring</generatorName>
    <apiPackage>at.my.api</apiPackage>
    <modelPackage>a.my.model</modelPackage>
    <configOptions>
        <dateLibrary>java8</dateLibrary>
        <library>spring-boot</library>
        <useOptional>true</useOptional>
        <useTags>true</useTags>
        <serializableModel>true</serializableModel>
        <booleanGetterPrefix>is</booleanGetterPrefix>
        <performBeanValidation>true</performBeanValidation>
        <useBeanValidation>true</useBeanValidation>
        <serializationLibrary>jackson</serializationLibrary>
        <additionalModelTypeAnnotations>
            @lombok.experimental.SuperBuilder
            @lombok.NoArgsConstructor
            @lombok.AllArgsConstructor
        </additionalModelTypeAnnotations>
    </configOptions>
</configuration>

Suggest a fix

quickly glanced the source of the Java generator and saw that api test folders are set, but did not check further.

[wing328]

We've not yet added auto-generated API test files to the spring generator: https://github.com/OpenAPITools/openapi-generator/blob/master/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/SpringCodegen.java#L145

and we would appreciate the contribution to add the enhancement.

May I know if you've time to file a PR?

We can take the Java client/server test mustache templates to start with and update accordingly.