#ifndef FILTER_TEST_CPP
#define FILTER_TEST_CPP
#include <gtest/gtest.h>
#include "filter.h"

TEST(PT1FilterTest, InitialOutputIsZero) {
    PT1Filter filter(0.1, 0.01);
    EXPECT_DOUBLE_EQ(filter.update(0.0), 0.0);
}

TEST(PT1FilterTest, StepResponse) {
    PT1Filter filter(0.1, 0.01);
    double output = 0.0;
    for (int i = 0; i < 100; ++i) {
        output = filter.update(1.0);
    }
    EXPECT_NEAR(output, 1.0, 0.01);
}

TEST(PT1FilterTest, FilterFactorEffect) {
    PT1Filter fastFilter(0.01, 0.01);
    PT1Filter slowFilter(0.5, 0.01);
    EXPECT_GT(fastFilter.update(1.0), slowFilter.update(1.0));
}

#endif // FILTER_TEST_CPP