Kotlin tests do not check using String methods

[alisevych]

Description

There are no meaningful tests generated for methods containing String methods calls in Kotlin.
Verified:

• trimMargin (String)
• matches (Regex)

To Reproduce

1. Install one of the latest builds of UnitTestBot plugin from main into IntelliJ Idea 2022.1.4
2. Create a project with Kotlin support
3. Use plugin to generate tests for the following Kotlin class:

public class StringTemplates {

    val month = "(JAN|FEB|MAR|APR|MAY|JUN|JUL|AUG|SEP|OCT|NOV|DEC)"

    fun getPattern(): String = """\d{2} $month \d{4}"""

    fun matchString(string: String) : Boolean {
        return string.matches(
                getPattern().toRegex())
    }
}

Expected behavior

At very least tests that do and do not match pattern are expected.
Also it would be great to generate some other "corner" cases:

• one digit at the beginning
• with JAN|FEB as the month
• with misprint JA as the month
• with 99 or 00 as the day
• etc.

Actual behavior

Generated Kotlin test contains two identical tests.

Visual proofs (screenshots, logs, images)

The following test class is generated:

public class StringTemplatesTest {
    ///region Test suites for executable koans.StringTemplates.matchString

    ///region

    /**
     * @utbot.classUnderTest {@link StringTemplates}
     * @utbot.methodUnderTest {@link StringTemplates#matchString(String)}
     */
    @Test
    @DisplayName("matchString: string = empty string -> return false")
    public void testMatchStringReturnsFalseWithEmptyString() {
        StringTemplates stringTemplates = new StringTemplates();

        boolean actual = stringTemplates.matchString("");

        assertFalse(actual);
    }
    ///endregion

    ///region FUZZER: SUCCESSFUL EXECUTIONS for method matchString(java.lang.String)

    /**
     * @utbot.classUnderTest {@link StringTemplates}
     * @utbot.methodUnderTest {@link StringTemplates#matchString(String)}
     */
    @Test
    @DisplayName("matchString: matchString: string = empty string -> return false")
    public void testMatchStringReturnsFalseWithEmptyString1() {
        StringTemplates stringTemplates = new StringTemplates();

        boolean actual = stringTemplates.matchString("");

        assertFalse(actual);
    }
    ///endregion

    ///endregion
}

Environment

Windows 10 Pro
IDEA 2022.1.4