[✨feat] CompanyCategory 구현

src/main/kotlin/com/terning/server/kotlin/domain/internshipAnnouncement/CompanyCategory.kt

@@ -0,0 +1,21 @@
+package com.terning.server.kotlin.domain.internshipAnnouncement
+
+enum class CompanyCategory(
+    val categoryId: Int,
+    val description: String,
+) {
+    LARGE_AND_MEDIUM_COMPANIES(0, "대기업/중견기업"),
+    SMALL_COMPANIES(1, "중소기업"),
+    PUBLIC_INSTITUTIONS(2, "공공기관/공기업"),
+    FOREIGN_COMPANIES(3, "외국계기업"),
+    STARTUPS(4, "스타트업"),
+    NON_PROFIT_ORGANIZATIONS(5, "비영리단체/재단"),
+    OTHERS(6, "기타"),
+    ;
+
+    companion object {
+        fun from(value: Int): CompanyCategory =
+            entries.firstOrNull { it.categoryId == value }
+                ?: throw InternshipException(InternshipErrorCode.INVALID_COMPANY_CATEGORY)
+    }
+}

src/main/kotlin/com/terning/server/kotlin/domain/internshipAnnouncement/InternshipErrorCode.kt

@@ -11,4 +11,5 @@ enum class InternshipErrorCode(
     INVALID_SCRAP_COUNT(HttpStatus.BAD_REQUEST, "스크랩 수는 음수일 수 없습니다."),
     SCRAP_COUNT_CANNOT_BE_DECREASED_BELOW_ZERO(HttpStatus.BAD_REQUEST, "스크랩 수는 0보다 작아질 수 없습니다."),
     INVALID_VIEW_COUNT(HttpStatus.BAD_REQUEST, "조회수는 음수일 수 없습니다."),
+    INVALID_COMPANY_CATEGORY(HttpStatus.BAD_REQUEST, "올바르지 않은 기업 구분 값입니다."),
 }

src/test/kotlin/com/terning/server/kotlin/domain/internshipAnnouncement/CompanyCategoryTest.kt

@@ -0,0 +1,43 @@
+package com.terning.server.kotlin.domain.internshipAnnouncement
+
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.DisplayName
+import org.junit.jupiter.api.assertThrows
+import org.junit.jupiter.params.ParameterizedTest
+import org.junit.jupiter.params.provider.CsvSource
+import org.junit.jupiter.params.provider.ValueSource
+
+class CompanyCategoryTest {
+    @DisplayName("유효한 categoryId를 전달하면 해당 CompanyCategory를 반환한다")
+    @ParameterizedTest(name = "categoryId {0} -> {1}")
+    @CsvSource(
+        "0, LARGE_AND_MEDIUM_COMPANIES",
+        "1, SMALL_COMPANIES",
+        "2, PUBLIC_INSTITUTIONS",
+        "3, FOREIGN_COMPANIES",
+        "4, STARTUPS",
+        "5, NON_PROFIT_ORGANIZATIONS",
+        "6, OTHERS",
+    )
+    fun `return correct CompanyCategory for valid categoryId`(
+        categoryId: Int,
+        expectedEnumName: String,
+    ) {
+        // when
+        val result = CompanyCategory.from(categoryId)
+        // then
+        assertThat(result.name).isEqualTo(expectedEnumName)
+    }
+
+    @DisplayName("유효하지 않은 categoryId를 전달하면 InternshipException을 던진다")
+    @ParameterizedTest(name = "categoryId {0} -> exception")
+    @ValueSource(ints = [-1, 7, 100, 999])
+    fun `throw exception when categoryId is invalid`(invalidCategoryId: Int) {
+        // when & then
+        val exception =
+            assertThrows<InternshipException> {
+                CompanyCategory.from(invalidCategoryId)
+            }
+        assertThat(exception.errorCode).isEqualTo(InternshipErrorCode.INVALID_COMPANY_CATEGORY)
+    }
+}