Class is identified as abstract and no tests are generated

[alisevych]

Description

ComplicatedMethodsSubstitutionsStorageTest is identified as abstract and no tests are generated

To Reproduce

1. Install -IU- UnitTestBot pluginin IntelliJ IDEA Ultimate 2023.2
2. Open utbot project
3. Generate tests for ComplicatedMethodsSubstitutionsStorageTest with default settings

Expected behavior

Some tests are expected to be generated

Actual behavior

No tests are generated with default settings.
Errors report is shown.

Screenshots, logs

Errors report for both methods:

        // Couldn't generate some tests. List of errors:
        // 
        // 1 occurrences of:
        /* We do not support testing for abstract classes (or interfaces)
        without any non-abstract inheritors (implementors). Probably, it'll be supported in
        the future. */

Environment

IntelliJ IDEA version - 2023.2 Ultimate
Project - Gradle
JDK - 17

Additional context

Fuzzing 100% generates tests for both methods.