test(recipe): cover null serves/cookTimeMin and capitalised effort rejection

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/src/test/java/com/recipeapp/recipe/RecipeControllerTest.java

@@ -161,6 +161,19 @@ class RecipeControllerTest {
         verify(recipeService).deleteRecipe(HOUSEHOLD_ID, RECIPE_ID);
     }
 
+    @Test
+    void createRecipeWithCapitalisedEffortShouldReturn400() throws Exception {
+        var body = """
+                {"name":"Test","effort":"Easy","tagIds":["%s"],"ingredients":[{"quantity":1,"unit":"g","newIngredientName":"x","sortOrder":0}]}
+                """.formatted(UUID.randomUUID());
+
+        mockMvc.perform(post("/v1/recipes")
+                        .principal(() -> "sarah@example.com")
+                        .contentType(org.springframework.http.MediaType.APPLICATION_JSON)
+                        .content(body))
+                .andExpect(status().isBadRequest());
+    }
+
     private RecipeCreateRequest sampleCreateRequest() {
         var ingredientId = UUID.randomUUID();
         return new RecipeCreateRequest(

backend/src/test/java/com/recipeapp/recipe/RecipeServiceTest.java

@@ -526,6 +526,29 @@ class RecipeServiceTest {
                 .isInstanceOf(ResourceNotFoundException.class);
     }
 
+    @Test
+    void createRecipeWithNullServesAndCookTimeShouldStoreZero() {
+        var household = testHousehold();
+        when(householdRepository.findById(HOUSEHOLD_ID)).thenReturn(Optional.of(household));
+        when(recipeRepository.save(any(Recipe.class))).thenAnswer(i -> {
+            Recipe r = i.getArgument(0);
+            try {
+                var field = Recipe.class.getDeclaredField("id");
+                field.setAccessible(true);
+                field.set(r, UUID.randomUUID());
+            } catch (Exception e) { throw new RuntimeException(e); }
+            return r;
+        });
+
+        var request = new RecipeCreateRequest("Soup", null, null, "easy", null,
+                List.of(), List.of(), List.of());
+
+        RecipeDetailResponse result = recipeService.createRecipe(HOUSEHOLD_ID, request);
+
+        assertThat(result.serves()).isEqualTo((short) 0);
+        assertThat(result.cookTimeMin()).isEqualTo((short) 0);
+    }
+
     // ── Tag/Category edge cases ──
 
     @Test