package de.aikiit.game.kaiser;
   
   import org.junit.jupiter.api.BeforeEach;
   import org.junit.jupiter.api.Test;
   
   import java.math.BigDecimal;
   
   import static org.assertj.core.api.Assertions.assertThat;
   import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
  
  class KaiserEngineTest {
  
      private KaiserEngine engine;
  
      @BeforeEach
      void createNewEngineUnderTest() {
          this.engine = new KaiserEngine();
      }
  
      @Test
      void getAreaPerCapita() {
          assertThat(engine.getAreaPerCapita()).isEqualTo(new BigDecimal("11"));
      }
  
      @Test
      void famineReducesPopulationDependingOnScaleFactorBeingBelowZero() {
          engine.setQ(new BigDecimal("-0.5"));
  
          engine.processFamine();
  
          assertThat(engine.getPopulation()).isEqualTo(new BigDecimal("48"));
          assertThat(engine.getQ()).isNotEqualByComparingTo(BigDecimal.ONE);
      }
  
      @Test
      void noPopulationReductionIfScaleFactorIsTooBig() {
          engine.setQ(new BigDecimal("12.34"));
  
          engine.processFamine();
  
          assertThat(engine.getPopulation()).isEqualTo(new BigDecimal("95"));
          assertThat(engine.getQ()).isNotEqualByComparingTo(BigDecimal.ONE);
      }
  
      @Test
      void buyLandIgnoresNegativeInputAndChangesNothing() {
          BigDecimal costB4 = engine.getCost();
          BigDecimal areaB4 = engine.getArea();
          BigDecimal supplyB4 = engine.getSupplies();
  
          engine.buyLand(-123L);
  
          assertThat(engine.getArea()).isEqualTo(areaB4);
          assertThat(engine.getSupplies()).isEqualTo(supplyB4);
          assertThat(engine.getCost()).isEqualTo(costB4);
      }
  
      @Test
      void calculateCostChangesPrice() {
          BigDecimal costB4 = engine.getCost();
  
          engine.calculateNewPrice();
  
          assertThat(engine.getCost()).isNotEqualTo(costB4);
      }
  
      @Test
      void verifyThingsHappenOnConstructorDefaultsUponFirstRoundRestart() {
          engine.startNewRound();
  
          assertThat(engine.getPopulation()).isEqualTo("100");
          assertThat(engine.getCost()).isPositive(); // randomNumber
          assertThat(engine.getArea()).isEqualTo("1000");
          assertThat(engine.getExternalDamage()).isEqualTo("200");
          assertThat(engine.getZYear()).isEqualTo(1);
          assertThat(engine.getYield()).isEqualTo(engine.getCost().add(BigDecimal.valueOf(17)));
      }
  
      @Test
      void verifyPostRoundActionsDoNotProduceErrors() {
          assertDoesNotThrow(() -> engine.finishRoundAfterActions());
      }
  }