diff --git a/composer.json b/composer.json
index 068ef756..acc66427 100644
--- a/composer.json
+++ b/composer.json
@@ -90,7 +90,7 @@
       "phpunit --colors --testsuite=unit"
     ],
     "infection": [
-      "./bin/infection --threads=8 --min-msi=98 --show-mutations"
+      "./bin/infection --threads=8 --min-msi=100 --show-mutations"
     ],
     "tests": [
       "@tests:unit"
diff --git a/tests/unit/DateTest.php b/tests/unit/DateTest.php
index 25049e8e..62ae1d5d 100644
--- a/tests/unit/DateTest.php
+++ b/tests/unit/DateTest.php
@@ -416,7 +416,9 @@ public function it_can_be_offset_by_days(int $days): void
 
         $expectedDate = Date::fromDateTime($date->startOfDay()->modify(\sprintf('%d days', $days)));
 
-        if ($days !== 0) {
+        if ($days === 0) {
+            $this->assertSame($date, $offsetDate);
+        } else {
             $this->assertNotSame($date, $offsetDate);
         }
 
@@ -447,7 +449,9 @@ public function it_can_be_offset_by_months(int $days): void
 
         $expectedDate = Date::fromDateTime($date->startOfDay()->modify(\sprintf('%d months', $days)));
 
-        if ($days !== 0) {
+        if ($days === 0) {
+            $this->assertSame($date, $offsetDate);
+        } else {
             $this->assertNotSame($date, $offsetDate);
         }
 
@@ -478,7 +482,9 @@ public function it_can_be_offset_by_years(int $days): void
 
         $expectedDate = Date::fromDateTime($date->startOfDay()->modify(\sprintf('%d years', $days)));
 
-        if ($days !== 0) {
+        if ($days === 0) {
+            $this->assertSame($date, $offsetDate);
+        } else {
             $this->assertNotSame($date, $offsetDate);
         }