Write unit tests for the RecipeRegister class

src/main/java/no/ntnu/idatt1002/demo/data/recipes/RecipeRegister.java

@@ -5,18 +5,27 @@ import java.util.List;
 
 public class RecipeRegister {
 
-    private List<Recipe> recipes = new ArrayList<>();
+    private final List<Recipe> recipes = new ArrayList<>();
 
 
     //TODO: Copy-constructor
 
+    public List<Recipe> getRecipes() {
+        return recipes;
+    }
+
     public void addRecipe (Recipe recipe) {
         if(recipes.contains(recipe)) {
             throw new IllegalArgumentException("The recipe already exists in the register."); // Or just replace?
         } else if (recipe == null) {
-            throw new IllegalArgumentException("The recipe cannot be null.");
+            throw new NullPointerException("The recipe cannot be null.");
         }
         this.recipes.add(recipe);
+    }
 
+    public Recipe getRecipe(String name) {
+        return recipes.stream().
+                filter((recipe) -> recipe.getName().equals(name))
+                        .findFirst().orElse(null);
     }
 }

src/test/java/no/ntnu/idatt1002/demo/data/recipes/RecipeRegisterTest.java

+package no.ntnu.idatt1002.demo.data.recipes;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class RecipeRegisterTest {
+
+    RecipeRegister myRecipes;
+
+    @BeforeEach
+    void beforeEach() {
+        myRecipes = new RecipeRegister();
+        myRecipes.addRecipe(new Recipe("Pasta al Limone", "Instructions"));
+    }
+
+    @Test
+    @DisplayName("Adding recipe to register successfully.")
+    void addRecipeToRegister() {
+        int numberOfRecipes = myRecipes.getRecipes().size();
+        myRecipes.addRecipe(new Recipe("Carbonara", "Instructions"));
+        assertEquals(numberOfRecipes + 1, myRecipes.getRecipes().size());
+    }
+
+    @Test
+    @DisplayName("Throw exception when adding already registered recipe.")
+    void recipeAlreadyInRegister() {
+        assertThrows(IllegalArgumentException.class, () -> myRecipes.addRecipe( new Recipe("Pasta al Limone", "Instructions")));
+    }
+
+    @Test
+    @DisplayName("Throw exception when adding null recipe.")
+    void addNullRecipe() {
+        assertThrows(NullPointerException.class, () -> myRecipes.addRecipe(null));
+    }
+
+    @Test
+    @DisplayName("Returns correct recipe based on name.")
+    void getRecipeByName() {
+        assertEquals(new Recipe("Pasta al Limone", "Instructions"), myRecipes.getRecipe("Pasta al Limone"));
+    }
+
+}
\ No newline at end of file