Test(expense): Expense 도메인 테스트 추가

Domain/Tests/ExpenseValidationTests.swift

@@ -178,4 +178,158 @@ struct ExpenseValidationTests {
         // when / then - 에러가 발생하지 않아야 함
         try expense.validate()
     }
+
+    // MARK: - ExpenseInput Validation Tests (TC-037, TC-038)
+
+    @Test("TC-037: ExpenseInput - 모든 필드 유효")
+    func validExpenseInput() throws {
+        let input = ExpenseInput(
+            title: "점심 식사",
+            amount: 50000.0,
+            currency: "KRW",
+            expenseDate: Date(),
+            category: .foodAndDrink,
+            payerId: "user1",
+            participantIds: ["user1", "user2", "user3"]
+        )
+
+        // when / then - 에러가 발생하지 않아야 함
+        try input.validate()
+    }
+
+    @Test("TC-038: ExpenseInput - 금액 검증 우선순위 확인")
+    func validationPriority_amountFirst() throws {
+        // Given - 여러 유효하지 않은 필드: 금액 음수, 제목 비어있음, 참가자 없음
+        let input = ExpenseInput(
+            title: "",
+            amount: -1000.0,
+            currency: "KRW",
+            expenseDate: Date(),
+            category: .foodAndDrink,
+            payerId: "user1",
+            participantIds: []
+        )
+
+        // When / Then - 금액 검증이 먼저 실행되어 invalidAmount 에러가 발생해야 함
+        #expect(throws: ExpenseError.invalidAmount(-1000.0)) {
+            try input.validate()
+        }
+    }
+
+    @Test("ExpenseInput - 금액이 0인 경우")
+    func expenseInput_zeroAmount() throws {
+        let input = ExpenseInput(
+            title: "테스트",
+            amount: 0.0,
+            currency: "KRW",
+            expenseDate: Date(),
+            category: .foodAndDrink,
+            payerId: "user1",
+            participantIds: ["user1"]
+        )
+
+        #expect(throws: ExpenseError.invalidAmount(0.0)) {
+            try input.validate()
+        }
+    }
+
+    @Test("ExpenseInput - 제목이 빈 문자열인 경우")
+    func expenseInput_emptyTitle() throws {
+        let input = ExpenseInput(
+            title: "",
+            amount: 10000.0,
+            currency: "KRW",
+            expenseDate: Date(),
+            category: .foodAndDrink,
+            payerId: "user1",
+            participantIds: ["user1"]
+        )
+
+        #expect(throws: ExpenseError.emptyTitle) {
+            try input.validate()
+        }
+    }
+
+    @Test("ExpenseInput - 제목이 공백만 있는 경우")
+    func expenseInput_whitespaceOnlyTitle() throws {
+        let input = ExpenseInput(
+            title: "   ",
+            amount: 10000.0,
+            currency: "KRW",
+            expenseDate: Date(),
+            category: .foodAndDrink,
+            payerId: "user1",
+            participantIds: ["user1"]
+        )
+
+        #expect(throws: ExpenseError.emptyTitle) {
+            try input.validate()
+        }
+    }
+
+    @Test("ExpenseInput - 참가자가 없는 경우")
+    func expenseInput_emptyParticipants() throws {
+        let input = ExpenseInput(
+            title: "테스트",
+            amount: 10000.0,
+            currency: "KRW",
+            expenseDate: Date(),
+            category: .foodAndDrink,
+            payerId: "user1",
+            participantIds: []
+        )
+
+        #expect(throws: ExpenseError.invalidParticipants) {
+            try input.validate()
+        }
+    }
+
+    @Test("ExpenseInput - 지불자가 참가자 목록에 없는 경우")
+    func expenseInput_payerNotInParticipants() throws {
+        let input = ExpenseInput(
+            title: "테스트",
+            amount: 10000.0,
+            currency: "KRW",
+            expenseDate: Date(),
+            category: .foodAndDrink,
+            payerId: "user1",
+            participantIds: ["user2", "user3"]
+        )
+
+        #expect(throws: ExpenseError.payerNotInParticipants) {
+            try input.validate()
+        }
+    }
+
+    @Test("ExpenseInput - 최소 유효 금액 (0.01)")
+    func expenseInput_minimumValidAmount() throws {
+        let input = ExpenseInput(
+            title: "최소 금액",
+            amount: 0.01,
+            currency: "KRW",
+            expenseDate: Date(),
+            category: .other,
+            payerId: "user1",
+            participantIds: ["user1"]
+        )
+
+        // 에러가 발생하지 않아야 함
+        try input.validate()
+    }
+
+    @Test("ExpenseInput - 매우 큰 금액")
+    func expenseInput_veryLargeAmount() throws {
+        let input = ExpenseInput(
+            title: "대용량 금액",
+            amount: 999_999_999.99,
+            currency: "KRW",
+            expenseDate: Date(),
+            category: .accommodation,
+            payerId: "user1",
+            participantIds: ["user1"]
+        )
+
+        // 에러가 발생하지 않아야 함
+        try input.validate()
+    }
 }