Written unit test for testing rxjava, but not sure if my unit test is testing everything

Android Studio 3.4

I have the following method that I am testing. Basically, what this test does is makes a request and that will return a LoginResponseEntity that will be mapped and return a Single<LoginResponse>

 override fun loginUserPost(username: String, password: String, uniqueIdentifier: String, deviceToken: String, apiToken: String) : Single<LoginResponse> {
            val loginRequestEntity = LoginRequestEntity(username, password, uniqueIdentifier, deviceToken)
            return loginAPIService.loginUserPost(loginRequestEntity, apiToken)
                .map {
                    loginResponseDomainMapper.map(it)
                }
    }

The test case I have written works, but I think that this is not fully testing this method.

     @Test
     fun `should return LoginResponse`() {
        val loginRequestEntity = LoginRequestEntity("username", "password", "uniqueidentifier", "devicetoken")
        val loginResponse = LoginResponse("token", createUser(), emptyList(), emptyList())
        val loginResponseEntity = LoginResponseEntity("token", createUserEntity(), emptyList(), emptyList())

        whenever(loginAPIService.loginUserPost(loginRequestEntity, "apitoken")).thenReturn(Single.just(loginResponseEntity))

        loginServiceImp.loginUserPost("username", "password", "uniqueidentifier", "devicetoken", "apitoken")
            .test()
            .assertValue(loginResponse)

        verify(loginAPIService).loginUserPost(loginRequestEntity, "apitoken")
    }

        private fun createUser() =
            User(
                "id",
                "email",
                "firstname",
                "lastname",
                "phone",
                "address",
                "dob",
                "customer",
                listOf("enterpriseids"),
                listOf("vendorids"))

        private fun createUserEntity() =
            UserEntity(
                "id",
                "email",
                "firstname",
                "lastname",
                "phone",
                "address",
                "dob",
                "customer",
                listOf("enterpriseids"),
                listOf("vendorids"))
    }

Is there anything more I can do to test this method. Should I be testing the .map{loginResponseDomainMapper.map(it) part of this method?

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