refactor: ThemeService에서의 정상 저장 테스트 추가

src/test/kotlin/roomescape/theme/business/ThemeServiceTest.kt

@@ -12,6 +12,7 @@ import roomescape.theme.exception.ThemeException
 import roomescape.theme.infrastructure.persistence.ThemeEntity
 import roomescape.theme.infrastructure.persistence.ThemeRepository
 import roomescape.theme.web.ThemeCreateRequest
+import roomescape.theme.web.ThemeRetrieveResponse
 import roomescape.util.ThemeFixture
 
 class ThemeServiceTest : FunSpec({
@@ -59,19 +60,43 @@ class ThemeServiceTest : FunSpec({
     }
 
     context("save") {
-        test("테마 이름이 중복되면 409 예외를 던진다.") {
-            val name = "Duplicate Theme"
+        val request = ThemeCreateRequest(
+                name = "New Theme",
+                description = "Description",
+                thumbnail = "http://example.com/thumbnail.jpg"
+        )
+
+        test("저장 성공") {
+            every {
+                themeRepository.existsByName(request.name)
+            } returns false
 
             every {
-                themeRepository.existsByName(name)
+                themeRepository.save(any())
+            } returns ThemeFixture.create(
+                    id = 1L,
+                    name = request.name,
+                    description = request.description,
+                    thumbnail = request.thumbnail
+            )
+
+            val response: ThemeRetrieveResponse = themeService.createTheme(request)
+
+            assertSoftly(response) {
+                this.id shouldBe 1L
+                this.name shouldBe request.name
+                this.description shouldBe request.description
+                this.thumbnail shouldBe request.thumbnail
+            }
+        }
+
+        test("테마 이름이 중복되면 409 예외를 던진다.") {
+            every {
+                themeRepository.existsByName(request.name)
             } returns true
 
             val exception = shouldThrow<ThemeException> {
-                themeService.createTheme(ThemeCreateRequest(
-                        name = name,
-                        description = "Description",
-                        thumbnail = "http://example.com/thumbnail.jpg"
-                ))
+                themeService.createTheme(request)
             }
 
             exception.errorCode shouldBe ThemeErrorCode.THEME_NAME_DUPLICATED