diff --git a/.travis.yml b/.travis.yml
index 5218cd2..6a380ff 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -21,6 +21,10 @@ install:
   - $COMPOSER_UP
 
 jobs:
+  allow_failures:
+    - php: nightly
+    - php: 7.4snapshot
+
   include:
     - stage: Test
       php: 7.1
@@ -31,6 +35,12 @@ jobs:
     - stage: Test
       php: 7.3
       env: REMOVE_XDEBUG=true
+    - stage: Test
+      php: 7.4snapshot
+#      env: REMOVE_XDEBUG=true
+    - stage: Test
+      php: nightly
+#      env: REMOVE_XDEBUG=true
 
     - stage: Coding standard
       if: type != cron
diff --git a/src/Config.php b/src/Config.php
index 5ca5efe..0d4a7e8 100644
--- a/src/Config.php
+++ b/src/Config.php
@@ -95,9 +95,6 @@ public function getRules(): array
                 'noise_remaining_usages' => false,
             ],
             'no_superfluous_phpdoc_tags'             => false,
-            'php_unit_test_case_static_method_calls' => [
-                'call_type' => 'this',
-            ],
             'fopen_flags'                            => false,
             'fopen_flag_order'                       => false,
             'php_unit_test_class_requires_covers'    => false,
diff --git a/tests/ConfigTest.php b/tests/ConfigTest.php
index 737f032..ec64372 100644
--- a/tests/ConfigTest.php
+++ b/tests/ConfigTest.php
@@ -38,14 +38,14 @@ final class ConfigTest extends TestCase
 {
     public function testImplementsInterface(): void
     {
-        $this->assertInstanceOf(ConfigInterface::class, new Config());
+        self::assertInstanceOf(ConfigInterface::class, new Config());
     }
 
     public function testValues(): void
     {
         $config = new Config();
 
-        $this->assertSame('narrowspark', $config->getName());
+        self::assertSame('narrowspark', $config->getName());
     }
 
     public function testHasPsr2Rules(): void
@@ -90,20 +90,20 @@ public function testIfAllRulesAreTested(): void
         $rules = (new Config())->getRules();
 
         foreach ($rules as $key => $value) {
-            $this->assertTrue(isset($testRules[$key]), '[' . $key . '] Rule is missing.');
+            self::assertTrue(isset($testRules[$key]), '[' . $key . '] Rule is missing.');
         }
 
-        $this->assertCount(\count($testRules), $rules);
+        self::assertCount(\count($testRules), $rules);
     }
 
     public function testDoesNotHaveHeaderCommentFixerByDefault(): void
     {
         $rules = (new Config())->getRules();
 
-        $this->assertArrayHasKey('header_comment', $rules);
-        $this->assertFalse($rules['header_comment']);
-        $this->assertTrue($rules['no_blank_lines_before_namespace']);
-        $this->assertFalse($rules['single_blank_line_before_namespace']);
+        self::assertArrayHasKey('header_comment', $rules);
+        self::assertFalse($rules['header_comment']);
+        self::assertTrue($rules['no_blank_lines_before_namespace']);
+        self::assertFalse($rules['single_blank_line_before_namespace']);
     }
 
     public function testHasHeaderCommentFixerIfProvided(): void
@@ -112,7 +112,7 @@ public function testHasHeaderCommentFixerIfProvided(): void
         $config = new Config($header);
         $rules  = $config->getRules();
 
-        $this->assertArrayHasKey('header_comment', $rules);
+        self::assertArrayHasKey('header_comment', $rules);
 
         $expected = [
             'comment_type' => 'PHPDoc',
@@ -120,9 +120,9 @@ public function testHasHeaderCommentFixerIfProvided(): void
             'location'     => 'after_declare_strict',
             'separate'     => 'both',
         ];
-        $this->assertSame($expected, $rules['header_comment']);
-        $this->assertTrue($rules['no_blank_lines_before_namespace']);
-        $this->assertFalse($rules['single_blank_line_before_namespace']);
+        self::assertSame($expected, $rules['header_comment']);
+        self::assertTrue($rules['no_blank_lines_before_namespace']);
+        self::assertFalse($rules['single_blank_line_before_namespace']);
     }
 
     public function testAllConfiguredRulesAreBuiltIn(): void
@@ -148,7 +148,7 @@ public function testAllConfiguredRulesAreBuiltIn(): void
             \array_merge($this->builtInFixers(), $pedroTrollerRules, $kubawerlosRules)
         );
 
-        $this->assertEmpty($fixersNotBuiltIn, \sprintf(
+        self::assertEmpty($fixersNotBuiltIn, \sprintf(
             'Failed to assert that fixers for the rules "%s" are built in',
             \implode('", "', $fixersNotBuiltIn)
         ));
@@ -168,13 +168,13 @@ public function testDoesNotHaveRulesEnabled(string $fixer, $reason): void
         ];
 
         if ($fixer === 'array_syntax') {
-            $this->assertNotSame(['syntax' => 'long'], $config->getRules()['array_syntax'], \sprintf(
+            self::assertNotSame(['syntax' => 'long'], $config->getRules()['array_syntax'], \sprintf(
                 'Fixer "%s" should not be enabled, because "%s"',
                 $fixer,
                 $reason['long']
             ));
         } else {
-            $this->assertArraySubset($rule, $config->getRules(), true, \sprintf(
+            self::assertArraySubset($rule, $config->getRules(), true, \sprintf(
                 'Fixer "%s" should not be enabled, because "%s"',
                 $fixer,
                 $reason
@@ -426,7 +426,7 @@ private function getPHPUnitRules(): array
                 'use_class_const' => true,
             ],
             'php_unit_test_case_static_method_calls' => [
-                'call_type' => 'this',
+                'call_type' => 'self',
             ],
             'php_unit_internal_class' => [
                 'types' => [
@@ -629,12 +629,12 @@ private function getSymfonyRules(): array
     private function assertHasRules(array $expected, array $actual, string $set): void
     {
         foreach ($expected as $fixer => $isEnabled) {
-            $this->assertArrayHasKey($fixer, $actual, \sprintf(
+            self::assertArrayHasKey($fixer, $actual, \sprintf(
                 'Failed to assert that a rule for fixer "%s" (in set "%s") exists.,',
                 $fixer,
                 $set
             ));
-            $this->assertSame($isEnabled, $actual[$fixer], \sprintf(
+            self::assertSame($isEnabled, $actual[$fixer], \sprintf(
                 'Failed to assert that fixer "%s" (in set "%s") is %s.',
                 $fixer,
                 $set,