diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/AllSetupTeardown.php b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/AllSetupTeardown.php
index 414670c4..9fb5dfa5 100644
--- a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/AllSetupTeardown.php
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/AllSetupTeardown.php
@@ -27,22 +27,20 @@ class AllSetupTeardown extends TestCase
     private $returnDateType;
 
     /**
-     * @var Spreadsheet
+     * @var ?Spreadsheet
      */
-    protected $spreadsheet;
+    private $spreadsheet;
 
     /**
-     * @var Worksheet
+     * @var ?Worksheet
      */
-    protected $sheet;
+    private $sheet;
 
     protected function setUp(): void
     {
         $this->compatibilityMode = Functions::getCompatibilityMode();
         $this->excelCalendar = Date::getExcelCalendar();
         $this->returnDateType = Functions::getReturnDateType();
-        $this->spreadsheet = new Spreadsheet();
-        $this->sheet = $this->spreadsheet->getActiveSheet();
     }
 
     protected function tearDown(): void
@@ -50,7 +48,11 @@ class AllSetupTeardown extends TestCase
         Date::setExcelCalendar($this->excelCalendar);
         Functions::setCompatibilityMode($this->compatibilityMode);
         Functions::setReturnDateType($this->returnDateType);
-        $this->spreadsheet->disconnectWorksheets();
+        $this->sheet = null;
+        if ($this->spreadsheet !== null) {
+            $this->spreadsheet->disconnectWorksheets();
+            $this->spreadsheet = null;
+        }
     }
 
     protected static function setMac1904(): void
@@ -82,4 +84,24 @@ class AllSetupTeardown extends TestCase
             $this->expectException(CalcException::class);
         }
     }
+
+    protected function getSpreadsheet(): Spreadsheet
+    {
+        if ($this->spreadsheet !== null) {
+            return $this->spreadsheet;
+        }
+        $this->spreadsheet = new Spreadsheet();
+
+        return $this->spreadsheet;
+    }
+
+    protected function getSheet(): Worksheet
+    {
+        if ($this->sheet !== null) {
+            return $this->sheet;
+        }
+        $this->sheet = $this->getSpreadsheet()->getActiveSheet();
+
+        return $this->sheet;
+    }
 }
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/DateDifTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/DateDifTest.php
index 3aa9446d..d7d69376 100644
--- a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/DateDifTest.php
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/DateDifTest.php
@@ -12,7 +12,7 @@ class DateDifTest extends AllSetupTeardown
     public function testDATEDIF($expectedResult, string $formula): void
     {
         $this->mightHaveException($expectedResult);
-        $sheet = $this->sheet;
+        $sheet = $this->getSheet();
         $sheet->getCell('B1')->setValue('1954-11-23');
         $sheet->getCell('A1')->setValue("=DATEDIF($formula)");
         self::assertSame($expectedResult, $sheet->getCell('A1')->getCalculatedValue());
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/DateTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/DateTest.php
index 2ba9d41d..5e884707 100644
--- a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/DateTest.php
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/DateTest.php
@@ -14,7 +14,7 @@ class DateTest extends AllSetupTeardown
     public function testDATE($expectedResult, string $formula): void
     {
         $this->mightHaveException($expectedResult);
-        $sheet = $this->sheet;
+        $sheet = $this->getSheet();
         $sheet->getCell('B1')->setValue('1954-11-23');
         $sheet->getCell('A1')->setValue("=DATE($formula)");
         self::assertEquals($expectedResult, $sheet->getCell('A1')->getCalculatedValue());
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/DateValueTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/DateValueTest.php
index cf37162a..521bde1f 100644
--- a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/DateValueTest.php
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/DateValueTest.php
@@ -15,7 +15,7 @@ class DateValueTest extends AllSetupTeardown
      */
     public function testDATEVALUE($expectedResult, string $dateValue): void
     {
-        $this->sheet->getCell('B1')->setValue('1954-07-20');
+        $this->getSheet()->getCell('B1')->setValue('1954-07-20');
         // Loop to avoid extraordinarily rare edge case where first calculation
         // and second do not take place on same day.
         $row = 0;
@@ -29,8 +29,8 @@ class DateValueTest extends AllSetupTeardown
                     $expectedResult = DateValue::fromString($replYMD);
                 }
             }
-            $this->sheet->getCell("A$row")->setValue("=DATEVALUE($dateValue)");
-            $result = $this->sheet->getCell("A$row")->getCalculatedValue();
+            $this->getSheet()->getCell("A$row")->setValue("=DATEVALUE($dateValue)");
+            $result = $this->getSheet()->getCell("A$row")->getCalculatedValue();
             $dtEnd = new DateTimeImmutable();
             $endDay = $dtEnd->format('d');
         } while ($startDay !== $endDay);
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/DayTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/DayTest.php
index dc8adf11..af196050 100644
--- a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/DayTest.php
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/DayTest.php
@@ -12,7 +12,7 @@ class DayTest extends AllSetupTeardown
     public function testDAY($expectedResultExcel, string $dateTimeValue): void
     {
         $this->mightHaveException($expectedResultExcel);
-        $sheet = $this->sheet;
+        $sheet = $this->getSheet();
         $sheet->getCell('B1')->setValue('1954-11-23');
         $sheet->getCell('A1')->setValue("=DAY($dateTimeValue)");
         self::assertSame($expectedResultExcel, $sheet->getCell('A1')->getCalculatedValue());
@@ -32,7 +32,7 @@ class DayTest extends AllSetupTeardown
     {
         self::setOpenOffice();
         $this->mightHaveException($expectedResultOpenOffice);
-        $sheet = $this->sheet;
+        $sheet = $this->getSheet();
         $sheet->getCell('A2')->setValue("=DAY($dateTimeValue)");
         self::assertSame($expectedResultOpenOffice, $sheet->getCell('A2')->getCalculatedValue());
     }
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/Days360Test.php b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/Days360Test.php
index bd3a0283..5a3e235d 100644
--- a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/Days360Test.php
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/Days360Test.php
@@ -12,7 +12,7 @@ class Days360Test extends AllSetupTeardown
     public function testDAYS360($expectedResult, string $formula): void
     {
         $this->mightHaveException($expectedResult);
-        $sheet = $this->sheet;
+        $sheet = $this->getSheet();
         $sheet->getCell('B1')->setValue('2000-02-29');
         $sheet->getCell('C1')->setValue('2000-03-31');
         $sheet->getCell('A1')->setValue("=DAYS360($formula)");
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/DaysTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/DaysTest.php
index e4db4f26..a63e45cc 100644
--- a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/DaysTest.php
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/DaysTest.php
@@ -17,7 +17,7 @@ class DaysTest extends AllSetupTeardown
     public function testDAYS($expectedResult, string $formula): void
     {
         $this->mightHaveException($expectedResult);
-        $sheet = $this->sheet;
+        $sheet = $this->getSheet();
         $sheet->getCell('B1')->setValue('1954-11-23');
         $sheet->getCell('C1')->setValue('1954-11-30');
         $sheet->getCell('A1')->setValue("=DAYS($formula)");
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/EDateTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/EDateTest.php
index b3b2bd25..22613fe5 100644
--- a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/EDateTest.php
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/EDateTest.php
@@ -14,7 +14,7 @@ class EDateTest extends AllSetupTeardown
     public function testEDATE($expectedResult, string $formula): void
     {
         $this->mightHaveException($expectedResult);
-        $sheet = $this->sheet;
+        $sheet = $this->getSheet();
         $sheet->getCell('A1')->setValue("=EDATE($formula)");
         $sheet->getCell('B1')->setValue('1954-11-23');
         self::assertEquals($expectedResult, $sheet->getCell('A1')->getCalculatedValue());
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/EoMonthTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/EoMonthTest.php
index 45e25e3b..3c39fbbc 100644
--- a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/EoMonthTest.php
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/EoMonthTest.php
@@ -14,7 +14,7 @@ class EoMonthTest extends AllSetupTeardown
     public function testEOMONTH($expectedResult, string $formula): void
     {
         $this->mightHaveException($expectedResult);
-        $sheet = $this->sheet;
+        $sheet = $this->getSheet();
         $sheet->getCell('A1')->setValue("=EOMONTH($formula)");
         $sheet->getCell('B1')->setValue('1954-11-23');
         self::assertEquals($expectedResult, $sheet->getCell('A1')->getCalculatedValue());
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/HourTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/HourTest.php
index 93afbb5d..c1e4f29c 100644
--- a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/HourTest.php
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/HourTest.php
@@ -12,7 +12,7 @@ class HourTest extends AllSetupTeardown
     public function testHOUR($expectedResult, string $dateTimeValue): void
     {
         $this->mightHaveException($expectedResult);
-        $sheet = $this->sheet;
+        $sheet = $this->getSheet();
         $sheet->getCell('A1')->setValue("=HOUR($dateTimeValue)");
         $sheet->getCell('B1')->setValue('1954-11-23 2:23:46');
         self::assertSame($expectedResult, $sheet->getCell('A1')->getCalculatedValue());
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/IsoWeekNumTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/IsoWeekNumTest.php
index 6be2e1af..29e35b38 100644
--- a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/IsoWeekNumTest.php
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/IsoWeekNumTest.php
@@ -13,7 +13,7 @@ class IsoWeekNumTest extends AllSetupTeardown
     public function testISOWEEKNUM($expectedResult, $dateValue): void
     {
         $this->mightHaveException($expectedResult);
-        $sheet = $this->sheet;
+        $sheet = $this->getSheet();
         $sheet->getCell('A1')->setValue("=ISOWEEKNUM($dateValue)");
         $sheet->getCell('B1')->setValue('1954-11-23');
         self::assertSame($expectedResult, $sheet->getCell('A1')->getCalculatedValue());
@@ -34,7 +34,7 @@ class IsoWeekNumTest extends AllSetupTeardown
     {
         $this->mightHaveException($expectedResult);
         self::setMac1904();
-        $sheet = $this->sheet;
+        $sheet = $this->getSheet();
         $sheet->getCell('A1')->setValue("=ISOWEEKNUM($dateValue)");
         $sheet->getCell('B1')->setValue('1954-11-23');
         self::assertSame($expectedResult, $sheet->getCell('A1')->getCalculatedValue());
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/MinuteTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/MinuteTest.php
index 57d7a77e..b5207d7e 100644
--- a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/MinuteTest.php
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/MinuteTest.php
@@ -12,7 +12,7 @@ class MinuteTest extends AllSetupTeardown
     public function testMINUTE($expectedResult, string $dateTimeValue): void
     {
         $this->mightHaveException($expectedResult);
-        $sheet = $this->sheet;
+        $sheet = $this->getSheet();
         $sheet->getCell('A1')->setValue("=MINUTE($dateTimeValue)");
         $sheet->getCell('B1')->setValue('1954-11-23 2:23:46');
         self::assertSame($expectedResult, $sheet->getCell('A1')->getCalculatedValue());
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/MonthTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/MonthTest.php
index ed09a993..30465e87 100644
--- a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/MonthTest.php
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/MonthTest.php
@@ -12,7 +12,7 @@ class MonthTest extends AllSetupTeardown
     public function testMONTH($expectedResult, string $dateTimeValue): void
     {
         $this->mightHaveException($expectedResult);
-        $sheet = $this->sheet;
+        $sheet = $this->getSheet();
         $sheet->getCell('A1')->setValue("=MONTH($dateTimeValue)");
         $sheet->getCell('B1')->setValue('1954-11-23');
         self::assertSame($expectedResult, $sheet->getCell('A1')->getCalculatedValue());
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/NetworkDaysTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/NetworkDaysTest.php
index b121f7bf..d6b1a89f 100644
--- a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/NetworkDaysTest.php
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/NetworkDaysTest.php
@@ -14,7 +14,7 @@ class NetworkDaysTest extends AllSetupTeardown
     public function testNETWORKDAYS($expectedResult, $arg1 = 'omitted', $arg2 = 'omitted', ?array $arg3 = null): void
     {
         $this->mightHaveException($expectedResult);
-        $sheet = $this->sheet;
+        $sheet = $this->getSheet();
         if ($arg1 !== null) {
             $sheet->getCell('A1')->setValue($arg1);
         }
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/NowTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/NowTest.php
index e0f68c24..42362b99 100644
--- a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/NowTest.php
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/NowTest.php
@@ -8,7 +8,7 @@ class NowTest extends AllSetupTeardown
 {
     public function testNow(): void
     {
-        $sheet = $this->sheet;
+        $sheet = $this->getSheet();
         // Loop to avoid rare edge case where first calculation
         // and second do not take place in same second.
         do {
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/SecondTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/SecondTest.php
index 6c264a57..1a411d45 100644
--- a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/SecondTest.php
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/SecondTest.php
@@ -12,7 +12,7 @@ class SecondTest extends AllSetupTeardown
     public function testSECOND($expectedResult, string $dateTimeValue): void
     {
         $this->mightHaveException($expectedResult);
-        $sheet = $this->sheet;
+        $sheet = $this->getSheet();
         $sheet->getCell('A1')->setValue("=SECOND($dateTimeValue)");
         $sheet->getCell('B1')->setValue('1954-11-23 2:23:46');
         self::assertSame($expectedResult, $sheet->getCell('A1')->getCalculatedValue());
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/TimeTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/TimeTest.php
index ae83f05a..3ee1aa55 100644
--- a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/TimeTest.php
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/TimeTest.php
@@ -14,7 +14,7 @@ class TimeTest extends AllSetupTeardown
     public function testTIME($expectedResult, string $formula): void
     {
         $this->mightHaveException($expectedResult);
-        $sheet = $this->sheet;
+        $sheet = $this->getSheet();
         $sheet->getCell('B1')->setValue('15');
         $sheet->getCell('B2')->setValue('32');
         $sheet->getCell('B3')->setValue('50');
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/TimeValueTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/TimeValueTest.php
index 23eb4f17..6995c312 100644
--- a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/TimeValueTest.php
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/TimeValueTest.php
@@ -15,7 +15,7 @@ class TimeValueTest extends AllSetupTeardown
     public function testTIMEVALUE($expectedResult, $timeValue): void
     {
         $this->mightHaveException($expectedResult);
-        $sheet = $this->sheet;
+        $sheet = $this->getSheet();
         $sheet->getCell('B1')->setValue('03:45:52');
         $sheet->getCell('A1')->setValue("=TIMEVALUE($timeValue)");
         $result = $sheet->getCell('A1')->getCalculatedValue();
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/TodayTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/TodayTest.php
index 6ce82bfd..b7108f75 100644
--- a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/TodayTest.php
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/TodayTest.php
@@ -8,7 +8,7 @@ class TodayTest extends AllSetupTeardown
 {
     public function testToday(): void
     {
-        $sheet = $this->sheet;
+        $sheet = $this->getSheet();
         // Loop to avoid rare edge case where first calculation
         // and second do not take place in same second.
         do {
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/WeekDayTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/WeekDayTest.php
index 625e4414..3c7f682d 100644
--- a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/WeekDayTest.php
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/WeekDayTest.php
@@ -14,7 +14,7 @@ class WeekDayTest extends AllSetupTeardown
     public function testWEEKDAY($expectedResult, string $formula): void
     {
         $this->mightHaveException($expectedResult);
-        $sheet = $this->sheet;
+        $sheet = $this->getSheet();
         $sheet->getCell('B1')->setValue('1954-11-23');
         $sheet->getCell('A1')->setValue("=WEEKDAY($formula)");
         self::assertSame($expectedResult, $sheet->getCell('A1')->getCalculatedValue());
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/WeekNumTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/WeekNumTest.php
index cf8ac65b..caa71f17 100644
--- a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/WeekNumTest.php
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/WeekNumTest.php
@@ -12,7 +12,7 @@ class WeekNumTest extends AllSetupTeardown
     public function testWEEKNUM($expectedResult, string $formula): void
     {
         $this->mightHaveException($expectedResult);
-        $sheet = $this->sheet;
+        $sheet = $this->getSheet();
         $sheet->getCell('B1')->setValue('1954-11-23');
         $sheet->getCell('A1')->setValue("=WEEKNUM($formula)");
         self::assertSame($expectedResult, $sheet->getCell('A1')->getCalculatedValue());
@@ -32,7 +32,7 @@ class WeekNumTest extends AllSetupTeardown
     {
         $this->mightHaveException($expectedResult);
         self::setMac1904();
-        $sheet = $this->sheet;
+        $sheet = $this->getSheet();
         $sheet->getCell('B1')->setValue('1954-11-23');
         $sheet->getCell('A1')->setValue("=WEEKNUM($formula)");
         self::assertSame($expectedResult, $sheet->getCell('A1')->getCalculatedValue());
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/WorkDayTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/WorkDayTest.php
index 80829699..3cfa9219 100644
--- a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/WorkDayTest.php
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/WorkDayTest.php
@@ -14,7 +14,7 @@ class WorkDayTest extends AllSetupTeardown
     public function testWORKDAY($expectedResult, $arg1 = 'omitted', $arg2 = 'omitted', ?array $arg3 = null): void
     {
         $this->mightHaveException($expectedResult);
-        $sheet = $this->sheet;
+        $sheet = $this->getSheet();
         if ($arg1 !== null) {
             $sheet->getCell('A1')->setValue($arg1);
         }
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/YearFracTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/YearFracTest.php
index e16ce697..d7427bfd 100644
--- a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/YearFracTest.php
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/YearFracTest.php
@@ -15,7 +15,7 @@ class YearFracTest extends AllSetupTeardown
     public function testYEARFRAC($expectedResult, $arg1 = 'omitted', $arg2 = 'omitted', $arg3 = 'omitted'): void
     {
         $this->mightHaveException($expectedResult);
-        $sheet = $this->sheet;
+        $sheet = $this->getSheet();
         if ($arg1 !== null) {
             $sheet->getCell('A1')->setValue($arg1);
         }
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/YearTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/YearTest.php
index 74b3bed0..a31ac7aa 100644
--- a/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/YearTest.php
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/DateTime/YearTest.php
@@ -12,7 +12,7 @@ class YearTest extends AllSetupTeardown
     public function testYEAR($expectedResult, string $dateTimeValue): void
     {
         $this->mightHaveException($expectedResult);
-        $sheet = $this->sheet;
+        $sheet = $this->getSheet();
         $sheet->getCell('A1')->setValue("=YEAR($dateTimeValue)");
         $sheet->getCell('B1')->setValue('1954-11-23');
         self::assertSame($expectedResult, $sheet->getCell('A1')->getCalculatedValue());