diff --git a/phpstan-baseline.neon b/phpstan-baseline.neon
index d6e95eaed0..9184a5cb67 100644
--- a/phpstan-baseline.neon
+++ b/phpstan-baseline.neon
@@ -515,11 +515,6 @@ parameters:
 			count: 1
 			path: src/PhpSpreadsheet/Calculation/FormulaParser.php
 
-		-
-			message: "#^Strict comparison using \\=\\=\\= between string and null will always evaluate to false\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Calculation/FormulaParser.php
-
 		-
 			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Calculation\\\\Functions\\:\\:ifCondition\\(\\) has no return type specified\\.$#"
 			count: 1
diff --git a/src/PhpSpreadsheet/Calculation/FormulaParser.php b/src/PhpSpreadsheet/Calculation/FormulaParser.php
index ddf45b23be..f71d96fc76 100644
--- a/src/PhpSpreadsheet/Calculation/FormulaParser.php
+++ b/src/PhpSpreadsheet/Calculation/FormulaParser.php
@@ -61,7 +61,7 @@ class FormulaParser
     /**
      * Create a new FormulaParser.
      *
-     * @param string $formula Formula to parse
+     * @param ?string $formula Formula to parse
      */
     public function __construct($formula = '')
     {
diff --git a/tests/PhpSpreadsheetTests/Calculation/FormulaParserTest.php b/tests/PhpSpreadsheetTests/Calculation/FormulaParserTest.php
new file mode 100644
index 0000000000..4682c6b2a2
--- /dev/null
+++ b/tests/PhpSpreadsheetTests/Calculation/FormulaParserTest.php
@@ -0,0 +1,151 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Calculation;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Exception as CalcException;
+use PhpOffice\PhpSpreadsheet\Calculation\FormulaParser;
+use PHPUnit\Framework\TestCase;
+
+class FormulaParserTest extends TestCase
+{
+    public function testNullFormula(): void
+    {
+        $this->expectException(CalcException::class);
+        $this->expectExceptionMessage('Invalid parameter passed: formula');
+        $result = new FormulaParser(null);
+    }
+
+    public function testInvalidTokenId(): void
+    {
+        $this->expectException(CalcException::class);
+        $this->expectExceptionMessage('Token with id 1 does not exist.');
+        $result = new FormulaParser('=2');
+        $result->getToken(1);
+    }
+
+    public function testNoFormula(): void
+    {
+        $result = new FormulaParser('');
+        self::assertSame(0, $result->getTokenCount());
+    }
+
+    /**
+     * @dataProvider providerFormulaParser
+     */
+    public function testFormulaParser(string $formula, array $expectedResult): void
+    {
+        $formula = "=$formula";
+        $result = new FormulaParser($formula);
+        self::assertSame($formula, $result->getFormula());
+        self::assertSame(count($expectedResult), $result->getTokenCount());
+        $tokens = $result->getTokens();
+        $token0 = $result->getToken(0);
+        self::assertSame($tokens[0], $token0);
+        $idx = -1;
+        foreach ($expectedResult as $resultArray) {
+            ++$idx;
+            self::assertSame($resultArray[0], $tokens[$idx]->getValue());
+            self::assertSame($resultArray[1], $tokens[$idx]->getTokenType());
+            self::assertSame($resultArray[2], $tokens[$idx]->getTokenSubType());
+        }
+    }
+
+    public function providerFormulaParser(): array
+    {
+        return [
+            ['5%*(2+(-3))+A3',
+                [
+                    ['5', 'Operand', 'Number'],
+                    ['%', 'OperatorPostfix', 'Nothing'],
+                    ['*', 'OperatorInfix', 'Math'],
+                    ['', 'Subexpression', 'Start'],
+                    ['2', 'Operand', 'Number'],
+                    ['+', 'OperatorInfix', 'Math'],
+                    ['', 'Subexpression', 'Start'],
+                    ['-', 'OperatorPrefix', 'Nothing'],
+                    ['3', 'Operand', 'Number'],
+                    ['', 'Subexpression', 'Stop'],
+                    ['', 'Subexpression', 'Stop'],
+                    ['+', 'OperatorInfix', 'Math'],
+                    ['A3', 'Operand', 'Range'],
+                ],
+            ],
+            ['"hello"  & "goodbye"',
+                [
+                    ['hello', 'Operand', 'Text'],
+                    ['&', 'OperatorInfix', 'Concatenation'],
+                    ['goodbye', 'Operand', 'Text'],
+                ],
+            ],
+            ['+1.23E5',
+                [
+                    ['1.23E5', 'Operand', 'Number'],
+                ],
+            ],
+            ['#DIV/0!',
+                [
+                    ['#DIV/0!', 'Operand', 'Error'],
+                ],
+            ],
+            ['"HE""LLO"',
+                [
+                    ['HE"LLO', 'Operand', 'Text'],
+                ],
+            ],
+            ['MINVERSE({3,1;4,2})',
+                [
+                    ['MINVERSE', 'Function', 'Start'],
+                    ['ARRAY', 'Function', 'Start'],
+                    ['ARRAYROW', 'Function', 'Start'],
+                    ['3', 'Operand', 'Number'],
+                    [',', 'OperatorInfix', 'Union'],
+                    ['1', 'Operand', 'Number'],
+                    ['', 'Function', 'Stop'],
+                    [',', 'Argument', 'Nothing'],
+                    ['ARRAYROW', 'Function', 'Start'],
+                    ['4', 'Operand', 'Number'],
+                    [',', 'OperatorInfix', 'Union'],
+                    ['2', 'Operand', 'Number'],
+                    ['', 'Function', 'Stop'],
+                    ['', 'Function', 'Stop'],
+                    ['', 'Function', 'Stop'],
+                ],
+            ],
+            ['[1,1]*5',
+                [
+                    ['[1,1]', 'Operand', 'Range'],
+                    ['*', 'OperatorInfix', 'Math'],
+                    ['5', 'Operand', 'Number'],
+                ],
+            ],
+            ['IF(A1>=0,2,3)',
+                [
+                    ['IF', 'Function', 'Start'],
+                    ['A1', 'Operand', 'Range'],
+                    ['>=', 'OperatorInfix', 'Logical'],
+                    ['0', 'Operand', 'Number'],
+                    [',', 'OperatorInfix', 'Union'],
+                    ['2', 'Operand', 'Number'],
+                    [',', 'OperatorInfix', 'Union'],
+                    ['3', 'Operand', 'Number'],
+                    ['', 'Function', 'Stop'],
+                ],
+            ],
+            ["'Worksheet'!A1:A3",
+                [
+                    ['Worksheet!A1:A3', 'Operand', 'Range'],
+                ],
+            ],
+            ["'Worksh''eet'!A1:A3",
+                [
+                    ['Worksh\'eet!A1:A3', 'Operand', 'Range'],
+                ],
+            ],
+            ['true',
+                [
+                    ['true', 'Operand', 'Logical'],
+                ],
+            ],
+        ];
+    }
+}