dota_factory/src/test/SimulationTest.cpp

#include "catch.hpp"

#include "ConfigLoader.h"
#include "GameConfig.h"
#include "Simulation.h"
#include "Tick.h"
#include "TickDriver.h"
#include "TestConfig.h"

// ---------------------------------------------------------------------------
// Simulation
// ---------------------------------------------------------------------------

TEST_CASE("Simulation::currentTick starts at 0", "[simulation]")
{
    const Simulation sim(loadTestConfig());

    REQUIRE(sim.getCurrentTick() == 0);
}

TEST_CASE("Simulation::tick increments currentTick by 1", "[simulation]")
{
    Simulation sim(loadTestConfig());

    sim.tick();

    REQUIRE(sim.getCurrentTick() == 1);
}

TEST_CASE("Simulation::tick 10 times yields currentTick == 10", "[simulation]")
{
    Simulation sim(loadTestConfig());

    for (int i = 0; i < 10; ++i)
    {
        sim.tick();
    }

    REQUIRE(sim.getCurrentTick() == 10);
}

TEST_CASE("Simulation::drainBeamFiredEvents returns empty initially", "[simulation]")
{
    Simulation sim(loadTestConfig());

    REQUIRE(sim.drainBeamFiredEvents().empty());
}

TEST_CASE("Simulation::drainBeamFiredEvents clears queue on drain", "[simulation]")
{
    Simulation sim(loadTestConfig());

    // First drain: empty.
    sim.drainBeamFiredEvents();

    // Second drain must also be empty (not a double-return).
    REQUIRE(sim.drainBeamFiredEvents().empty());
}

TEST_CASE("Simulation::hasSchematicChoicesPending returns false initially", "[simulation]")
{
    Simulation sim(loadTestConfig());

    REQUIRE_FALSE(sim.hasSchematicChoicesPending());
}

// ---------------------------------------------------------------------------
// TickDriver
// ---------------------------------------------------------------------------

TEST_CASE("TickDriver: 0x speed never produces ticks", "[simulation]")
{
    TickDriver driver;

    REQUIRE(driver.advance(100.0, 0.0) == 0);
    REQUIRE(driver.advance(1000.0, 0.0) == 0);
}

TEST_CASE("TickDriver: exactly one tick duration at 1x produces 1 tick", "[simulation]")
{
    TickDriver driver;

    REQUIRE(driver.advance(kTickDurationMs, 1.0) == 1);
}

TEST_CASE("TickDriver: two tick durations at 1x produces 2 ticks", "[simulation]")
{
    TickDriver driver;

    REQUIRE(driver.advance(2.0 * kTickDurationMs, 1.0) == 2);
}

TEST_CASE("TickDriver: 4x speed with quarter tick duration produces 1 tick", "[simulation]")
{
    TickDriver driver;

    REQUIRE(driver.advance(kTickDurationMs / 4.0, 4.0) == 1);
}

TEST_CASE("TickDriver: 0.5x speed with double tick duration produces 1 tick", "[simulation]")
{
    TickDriver driver;

    REQUIRE(driver.advance(kTickDurationMs / 0.5, 0.5) == 1);
}

TEST_CASE("TickDriver: accumulator carries partial progress across frames", "[simulation]")
{
    TickDriver driver;

    // 60% of a tick — not enough to fire yet.
    REQUIRE(driver.advance(kTickDurationMs * 0.6, 1.0) == 0);

    // Another 60% — cumulative 120%, so exactly 1 tick fires.
    REQUIRE(driver.advance(kTickDurationMs * 0.6, 1.0) == 1);
}

TEST_CASE("TickDriver::reset clears the accumulator", "[simulation]")
{
    TickDriver driver;

    // Advance to just below one tick.
    driver.advance(kTickDurationMs * 0.9, 1.0);

    driver.reset();

    // Nothing in the accumulator: zero elapsed time should not fire.
    REQUIRE(driver.advance(0.0, 1.0) == 0);
}

TEST_CASE("TickDriver::reset discards a large pending delta so a restart does not "
          "fast-forward", "[simulation]")
{
    // Regression guard for the "restart fast-forwards by the time spent in the
    // Game Over / Win / escape dialog" bug: on restart the frame timer holds the
    // whole wall-clock duration the modal was open. GameWorldView::resetForNewGame()
    // now calls TickDriver::reset() to discard that pending delta; without it the
    // fresh run would burst forward by the dialog duration on its first frame.
    TickDriver driver;

    // 30 seconds spent in the dialog would otherwise be ~900 ticks at 30 Hz.
    const double dialogOpenMs = 30000.0;
    driver.reset();

    // A brand-new run's first normal frame (~16 ms) advances only its own ticks;
    // the discarded dialog time contributes nothing.
    REQUIRE(driver.advance(16.0, 1.0) == 0);

    // Sanity: had the dialog delta not been discarded, it would have fired ~900 ticks.
    TickDriver leaked;
    REQUIRE(leaked.advance(dialogOpenMs, 1.0) > 800);
}