diff --git a/Tests/Command/LintCommandTest.php b/Tests/Command/LintCommandTest.php
index 90e20455..4d3024cc 100644
--- a/Tests/Command/LintCommandTest.php
+++ b/Tests/Command/LintCommandTest.php
@@ -179,7 +179,7 @@ public function testComplete(array $input, array $expectedSuggestions)
         $this->assertSame($expectedSuggestions, $tester->complete($input));
     }
 
-    public function provideCompletionSuggestions()
+    public static function provideCompletionSuggestions()
     {
         yield 'option' => [['--format', ''], ['txt', 'json', 'github']];
     }
diff --git a/Tests/DumperTest.php b/Tests/DumperTest.php
index 16551f18..721b04ca 100644
--- a/Tests/DumperTest.php
+++ b/Tests/DumperTest.php
@@ -225,7 +225,7 @@ public function testEscapedEscapeSequencesInQuotedScalar($input, $expected)
         $this->assertSameData($input, $this->parser->parse($expected));
     }
 
-    public function getEscapeSequences()
+    public static function getEscapeSequences()
     {
         return [
             'empty string' => ['', "''"],
@@ -275,7 +275,7 @@ public function testDumpObjectAsMap($object, $expected)
         $this->assertSameData($expected, $this->parser->parse($yaml, Yaml::PARSE_OBJECT_FOR_MAP));
     }
 
-    public function objectAsMapProvider()
+    public static function objectAsMapProvider()
     {
         $tests = [];
 
diff --git a/Tests/InlineTest.php b/Tests/InlineTest.php
index f71509d2..8cd2582f 100644
--- a/Tests/InlineTest.php
+++ b/Tests/InlineTest.php
@@ -56,7 +56,7 @@ public function testParsePhpConstants($yaml, $value)
         $this->assertSame($value, $actual);
     }
 
-    public function getTestsForParsePhpConstants()
+    public static function getTestsForParsePhpConstants()
     {
         return [
             ['!php/const Symfony\Component\Yaml\Yaml::PARSE_CONSTANT', Yaml::PARSE_CONSTANT],
@@ -195,7 +195,7 @@ public function testParseReferences($yaml, $expected)
         $this->assertSame($expected, Inline::parse($yaml, 0, $references));
     }
 
-    public function getDataForParseReferences()
+    public static function getDataForParseReferences()
     {
         return [
             'scalar' => ['*var', 'var-value'],
@@ -245,7 +245,7 @@ public function testParseUnquotedScalarStartingWithReservedIndicator($indicator)
         Inline::parse(sprintf('{ foo: %sfoo }', $indicator));
     }
 
-    public function getReservedIndicators()
+    public static function getReservedIndicators()
     {
         return [['@'], ['`']];
     }
@@ -261,7 +261,7 @@ public function testParseUnquotedScalarStartingWithScalarIndicator($indicator)
         Inline::parse(sprintf('{ foo: %sfoo }', $indicator));
     }
 
-    public function getScalarIndicators()
+    public static function getScalarIndicators()
     {
         return [['|'], ['>'], ['%']];
     }
@@ -274,7 +274,7 @@ public function testIsHash($array, $expected)
         $this->assertSame($expected, Inline::isHash($array));
     }
 
-    public function getDataForIsHash()
+    public static function getDataForIsHash()
     {
         return [
             [[], false],
@@ -284,7 +284,7 @@ public function getDataForIsHash()
         ];
     }
 
-    public function getTestsForParse()
+    public static function getTestsForParse()
     {
         return [
             ['', ''],
@@ -370,7 +370,7 @@ public function getTestsForParse()
         ];
     }
 
-    public function getTestsForParseWithMapObjects()
+    public static function getTestsForParseWithMapObjects()
     {
         return [
             ['', ''],
@@ -451,7 +451,7 @@ public function getTestsForParseWithMapObjects()
         ];
     }
 
-    public function getTestsForDump()
+    public static function getTestsForDump()
     {
         return [
             ['null', null],
@@ -549,7 +549,7 @@ public function testParseTimestampAsDateTimeObject(string $yaml, int $year, int
         $this->assertSame($timezone, $date->format('O'));
     }
 
-    public function getTimestampTests(): array
+    public static function getTimestampTests(): array
     {
         return [
             'canonical' => ['2001-12-15T02:59:43.1Z', 2001, 12, 15, 2, 59, 43, 100000, '+0000'],
@@ -591,7 +591,7 @@ public function testDumpUnitEnum()
         $this->assertSame("!php/const Symfony\Component\Yaml\Tests\Fixtures\FooUnitEnum::BAR", Inline::dump(FooUnitEnum::BAR));
     }
 
-    public function getDateTimeDumpTests()
+    public static function getDateTimeDumpTests()
     {
         $tests = [];
 
@@ -612,7 +612,7 @@ public function testParseBinaryData($data)
         $this->assertSame('Hello world', Inline::parse($data));
     }
 
-    public function getBinaryData()
+    public static function getBinaryData()
     {
         return [
             'enclosed with double quotes' => ['!!binary "SGVsbG8gd29ybGQ="'],
@@ -632,7 +632,7 @@ public function testParseInvalidBinaryData($data, $expectedMessage)
         Inline::parse($data);
     }
 
-    public function getInvalidBinaryData()
+    public static function getInvalidBinaryData()
     {
         return [
             'length not a multiple of four' => ['!!binary "SGVsbG8d29ybGQ="', '/The normalized base64 encoded data \(data without whitespace characters\) length must be a multiple of four \(\d+ bytes given\)/'],
@@ -674,7 +674,7 @@ public function testParseMissingMappingValueAsNull($yaml, $expected)
         $this->assertSame($expected, Inline::parse($yaml));
     }
 
-    public function getTestsForNullValues()
+    public static function getTestsForNullValues()
     {
         return [
             'null before closing curly brace' => ['{foo:}', ['foo' => null]],
@@ -697,7 +697,7 @@ public function testImplicitStringCastingOfMappingKeysIsDeprecated($yaml, $expec
         $this->assertSame($expected, Inline::parse($yaml));
     }
 
-    public function getNotPhpCompatibleMappingKeyData()
+    public static function getNotPhpCompatibleMappingKeyData()
     {
         return [
             'boolean-true' => ['{true: "foo"}', ['true' => 'foo']],
@@ -776,7 +776,7 @@ public function testParseOctalNumbers($expected, $yaml)
         self::assertSame($expected, Inline::parse($yaml));
     }
 
-    public function getTestsForOctalNumbers()
+    public static function getTestsForOctalNumbers()
     {
         return [
             'positive octal number' => [28, '0o34'],
@@ -797,7 +797,7 @@ public function testParseOctalNumbersYaml11Notation(int $expected, string $yaml,
         self::assertSame($expected, Inline::parse($yaml));
     }
 
-    public function getTestsForOctalNumbersYaml11Notation()
+    public static function getTestsForOctalNumbersYaml11Notation()
     {
         return [
             'positive octal number' => [28, '034', '0o34'],
@@ -818,7 +818,7 @@ public function testPhpObjectWithEmptyValue($expected, $value)
         $this->assertSame($expected, Inline::parse($value, Yaml::PARSE_OBJECT));
     }
 
-    public function phpObjectTagWithEmptyValueProvider()
+    public static function phpObjectTagWithEmptyValueProvider()
     {
         return [
             [false, '!php/object'],
@@ -842,7 +842,7 @@ public function testPhpConstTagWithEmptyValue($expected, $value)
         $this->assertSame($expected, Inline::parse($value, Yaml::PARSE_CONSTANT));
     }
 
-    public function phpConstTagWithEmptyValueProvider()
+    public static function phpConstTagWithEmptyValueProvider()
     {
         return [
             ['', '!php/const'],
@@ -894,7 +894,7 @@ public function testUnquotedExclamationMarkThrows(string $value)
         Inline::parse($value);
     }
 
-    public function unquotedExclamationMarkThrowsProvider()
+    public static function unquotedExclamationMarkThrowsProvider()
     {
         return [
             ['!'],
@@ -926,7 +926,7 @@ public function testQuotedExclamationMark($expected, string $value)
     }
 
     // This provider should stay consistent with unquotedExclamationMarkThrowsProvider
-    public function quotedExclamationMarkProvider()
+    public static function quotedExclamationMarkProvider()
     {
         return [
             ['!', '"!"'],
@@ -956,7 +956,7 @@ public function testParseIdeographicSpace(string $yaml, string $expected)
         $this->assertSame($expected, Inline::parse($yaml));
     }
 
-    public function ideographicSpaceProvider(): array
+    public static function ideographicSpaceProvider(): array
     {
         return [
             ["\u{3000}", '　'],
diff --git a/Tests/ParserTest.php b/Tests/ParserTest.php
index b09ff090..98e5e73e 100644
--- a/Tests/ParserTest.php
+++ b/Tests/ParserTest.php
@@ -144,7 +144,7 @@ public function testTabsAsIndentationInYaml(string $given, string $expectedMessa
         $this->parser->parse($given);
     }
 
-    public function invalidIndentation(): array
+    public static function invalidIndentation(): array
     {
         return [
             [
@@ -189,7 +189,7 @@ public function testValidTokenSeparation(string $given, array $expected)
         $this->assertSameData($expected, $actual);
     }
 
-    public function validTokenSeparators(): array
+    public static function validTokenSeparators(): array
     {
         return [
             [
@@ -222,7 +222,7 @@ public function testEndOfTheDocumentMarker()
         $this->assertEquals('foo', $this->parser->parse($yaml));
     }
 
-    public function getBlockChompingTests()
+    public static function getBlockChompingTests()
     {
         $tests = [];
 
@@ -586,7 +586,7 @@ public function testObjectForMap($yaml, $expected)
         $this->assertSameData($expected, $this->parser->parse($yaml, $flags));
     }
 
-    public function getObjectForMapTests()
+    public static function getObjectForMapTests()
     {
         $tests = [];
 
@@ -833,7 +833,7 @@ public function testNonStringFollowedByCommentEmbeddedInMapping()
         $this->assertSame($expected, $this->parser->parse($yaml));
     }
 
-    public function getParseExceptionNotAffectedMultiLineStringLastResortParsing()
+    public static function getParseExceptionNotAffectedMultiLineStringLastResortParsing()
     {
         $tests = [];
 
@@ -975,7 +975,7 @@ public function testParseExceptionOnDuplicate($input, $duplicateKey, $lineNumber
         Yaml::parse($input);
     }
 
-    public function getParseExceptionOnDuplicateData()
+    public static function getParseExceptionOnDuplicateData()
     {
         $tests = [];
 
@@ -1280,7 +1280,7 @@ public function testCommentLikeStringsAreNotStrippedInBlockScalars($yaml, $expec
         $this->assertSame($expectedParserResult, $this->parser->parse($yaml));
     }
 
-    public function getCommentLikeStringInScalarBlockData()
+    public static function getCommentLikeStringInScalarBlockData()
     {
         $tests = [];
 
@@ -1465,7 +1465,7 @@ public function testParseBinaryData($data)
         $this->assertSame(['data' => 'Hello world'], $this->parser->parse($data));
     }
 
-    public function getBinaryData()
+    public static function getBinaryData()
     {
         return [
             'enclosed with double quotes' => ['data: !!binary "SGVsbG8gd29ybGQ="'],
@@ -1497,7 +1497,7 @@ public function testParseInvalidBinaryData($data, $expectedMessage)
         $this->parser->parse($data);
     }
 
-    public function getInvalidBinaryData()
+    public static function getInvalidBinaryData()
     {
         return [
             'length not a multiple of four' => ['data: !!binary "SGVsbG8d29ybGQ="', '/The normalized base64 encoded data \(data without whitespace characters\) length must be a multiple of four \(\d+ bytes given\)/'],
@@ -1563,7 +1563,7 @@ public function testParserThrowsExceptionWithCorrectLineNumber($lineNumber, $yam
         $this->parser->parse($yaml);
     }
 
-    public function parserThrowsExceptionWithCorrectLineNumberProvider()
+    public static function parserThrowsExceptionWithCorrectLineNumberProvider()
     {
         return [
             [
@@ -1720,7 +1720,7 @@ public function testParseQuotedStringContainingEscapedQuotationCharacters(string
         $this->assertSame($expected, $this->parser->parse($yaml));
     }
 
-    public function escapedQuotationCharactersInQuotedStrings()
+    public static function escapedQuotationCharactersInQuotedStrings()
     {
         return [
             'single quoted string' => [
@@ -1778,7 +1778,7 @@ public function testParseMultiLineMappingValue($yaml, $expected, $parseError)
         $this->assertSame($expected, $this->parser->parse($yaml));
     }
 
-    public function multiLineDataProvider()
+    public static function multiLineDataProvider()
     {
         $tests = [];
 
@@ -1845,7 +1845,7 @@ public function testInlineNotationSpanningMultipleLines($expected, string $yaml)
         $this->assertSame($expected, $this->parser->parse($yaml));
     }
 
-    public function inlineNotationSpanningMultipleLinesProvider(): array
+    public static function inlineNotationSpanningMultipleLinesProvider(): array
     {
         return [
             'mapping' => [
@@ -2234,7 +2234,7 @@ public function testCustomTagSupport($expected, $yaml)
         $this->assertSameData($expected, $this->parser->parse($yaml, Yaml::PARSE_CUSTOM_TAGS));
     }
 
-    public function taggedValuesProvider()
+    public static function taggedValuesProvider()
     {
         return [
             'scalars' => [
@@ -2658,7 +2658,7 @@ public function testDetectCircularReferences($yaml)
         $this->parser->parse($yaml, Yaml::PARSE_CUSTOM_TAGS);
     }
 
-    public function circularReferenceProvider()
+    public static function circularReferenceProvider()
     {
         $tests = [];
 
@@ -2698,7 +2698,7 @@ public function testParseIndentedMappings($yaml, $expected)
         $this->assertSame($expected, $this->parser->parse($yaml));
     }
 
-    public function indentedMappingData()
+    public static function indentedMappingData()
     {
         $tests = [];