[DateInterval] Modify tests to confirm that #4588 is resolved.

Author: YOCKOW

Tests/Foundation/Tests/TestDateInterval.swift

@@ -118,14 +118,25 @@ class TestDateInterval: XCTestCase {
     }
 
     func test_contains() {
+        let date0 = dateWithString("1964-10-01 06:00:00 +0900")
         let date1 = dateWithString("2019-04-04 17:00:00 -0700")
         let date2 = dateWithString("2019-04-04 17:30:00 -0700")
         let date3 = dateWithString("2019-04-04 17:45:00 -0700")
         let date4 = dateWithString("2019-04-04 17:50:00 -0700")
-        let dateInterval = DateInterval(start: date1, duration: 60 * 45)
-        XCTAssertTrue(dateInterval.contains(date2))
-        XCTAssertTrue(dateInterval.contains(date3))
-        XCTAssertFalse(dateInterval.contains(date4))
+
+        func __assert(interval: DateInterval, date: Date, expectedResult: Bool,
+                      file: StaticString = #file, line: UInt = #line) {
+            XCTAssertEqual(interval.contains(date), expectedResult, file: file, line: line)
+        }
+
+        __assert(interval: .init(start: .distantPast, end: .distantFuture), date: date0, expectedResult: true)
+        __assert(interval: .init(start: .distantPast, end: date1), date: date0, expectedResult: true)
+        __assert(interval: .init(start: .distantPast, end: date1), date: date2, expectedResult: false)
+        __assert(interval: .init(start: date0, end: date4), date: date2, expectedResult: true)
+        __assert(interval: .init(start: date1, duration: 60 * 45), date: date3, expectedResult: true)
+        __assert(interval: .init(start: date1, duration: 60 * 45), date: date4, expectedResult: false)
+        __assert(interval: .init(start: date2, end: .distantFuture), date: date2, expectedResult: true)
+        __assert(interval: .init(start: date2, end: .distantFuture), date: date0, expectedResult: false)
     }
 
     func test_hashing() {