diff --git a/ext/tests/php70/array_rand.phpt b/ext/tests/php70/array_rand.phpt
index 41efc25..6195004 100644
--- a/ext/tests/php70/array_rand.phpt
+++ b/ext/tests/php70/array_rand.phpt
@@ -6,7 +6,7 @@ colopl_bc
 date.timezone=UTC
 --SKIPIF--
 <?php
-if (PHP_ZTS !== 0) print 'skip ZTS not supported'; 
+if ((bool) PHP_ZTS === true) print 'skip ZTS not supported'; 
 ?>
 --FILE--
 <?php
diff --git a/ext/tests/php70/array_rand_zts.phpt b/ext/tests/php70/array_rand_zts.phpt
index 08540be..57015d3 100644
--- a/ext/tests/php70/array_rand_zts.phpt
+++ b/ext/tests/php70/array_rand_zts.phpt
@@ -6,7 +6,7 @@ colopl_bc
 date.timezone=UTC
 --SKIPIF--
 <?php
-if (PHP_ZTS === 0 || PHP_ZTS === false) print 'skip NTS not supported';
+if ((bool) PHP_ZTS === false) print 'skip NTS not supported';
 ?>
 --FILE--
 <?php
diff --git a/ext/tests/php70/shuffle.phpt b/ext/tests/php70/shuffle.phpt
index 3050c33..7a23910 100644
--- a/ext/tests/php70/shuffle.phpt
+++ b/ext/tests/php70/shuffle.phpt
@@ -6,7 +6,7 @@ colopl_bc
 date.timezone=UTC
 --SKIPIF--
 <?php
-if (PHP_ZTS !== 0) print 'skip ZTS not supported'; 
+if ((bool) PHP_ZTS === true) print 'skip ZTS not supported'; 
 ?>
 --FILE--
 <?php
diff --git a/ext/tests/php70/shuffle_zts.phpt b/ext/tests/php70/shuffle_zts.phpt
index cd91330..2ad5a16 100644
--- a/ext/tests/php70/shuffle_zts.phpt
+++ b/ext/tests/php70/shuffle_zts.phpt
@@ -6,7 +6,7 @@ colopl_bc
 date.timezone=UTC
 --SKIPIF--
 <?php
-if (PHP_ZTS === 0 || PHP_ZTS === false) print 'skip NTS not supported';
+if ((bool) PHP_ZTS === false) print 'skip NTS not supported';
 ?>
 --FILE--
 <?php
diff --git a/ext/tests/php70/str_shuffle.phpt b/ext/tests/php70/str_shuffle.phpt
index 0dc5cf9..4be1037 100644
--- a/ext/tests/php70/str_shuffle.phpt
+++ b/ext/tests/php70/str_shuffle.phpt
@@ -6,7 +6,7 @@ colopl_bc
 date.timezone=UTC
 --SKIPIF--
 <?php
-if (PHP_ZTS !== 0) print 'skip ZTS not supported'; 
+if ((bool) PHP_ZTS === true) print 'skip ZTS not supported'; 
 ?>
 --FILE--
 <?php
diff --git a/ext/tests/php70/str_shuffle_zts.phpt b/ext/tests/php70/str_shuffle_zts.phpt
index e97176c..f9df75a 100644
--- a/ext/tests/php70/str_shuffle_zts.phpt
+++ b/ext/tests/php70/str_shuffle_zts.phpt
@@ -6,7 +6,7 @@ colopl_bc
 date.timezone=UTC
 --SKIPIF--
 <?php
-if (PHP_ZTS === 0 || PHP_ZTS === false) print 'skip NTS not supported';
+if ((bool) PHP_ZTS === false) print 'skip NTS not supported';
 ?>
 --FILE--
 <?php
diff --git a/ext/tests/php70/undefined_behavior_compatibility.phpt b/ext/tests/php70/undefined_behavior_compatibility.phpt
index c9f18c2..8a072ec 100644
--- a/ext/tests/php70/undefined_behavior_compatibility.phpt
+++ b/ext/tests/php70/undefined_behavior_compatibility.phpt
@@ -6,7 +6,7 @@ colopl_bc
 date.timezone=UTC
 --SKIPIF--
 <?php
-if (PHP_ZTS !== 0) print 'skip ZTS not supported'; 
+if ((bool) PHP_ZTS === true) print 'skip ZTS not supported'; 
 if (PHP_INT_SIZE !== 8) die("skip this test is for 64bit platform only");
 ?>
 --FILE--
diff --git a/tests/Extension/PHP70Test.php b/tests/Extension/PHP70Test.php
index 52d3b7f..3eb76cc 100644
--- a/tests/Extension/PHP70Test.php
+++ b/tests/Extension/PHP70Test.php
@@ -21,7 +21,7 @@ public function testSRand(): void
     {
         \Colopl\ColoplBc\Php70\srand(1234);
 
-        if (\PHP_ZTS === 0) {
+        if ((bool) \PHP_ZTS === false) {
             self::assertSame(\Colopl\ColoplBc\Php70\rand(), 479142414);
         } else {
             self::assertSame(\Colopl\ColoplBc\Php70\rand(), 1584308507);
@@ -43,7 +43,7 @@ public function testSRandNull(): void
          * @psalm-suppress PossiblyNullArgument
          */
         \Colopl\ColoplBc\Php70\srand($seed);
-        if (\PHP_ZTS === 0) {
+        if ((bool) \PHP_ZTS === false) {
             self::assertSame(\Colopl\ColoplBc\Php70\rand(), 1804289383);
         } else {
             self::assertSame(\Colopl\ColoplBc\Php70\rand(), 1012484);
@@ -53,7 +53,7 @@ public function testSRandNull(): void
     public function testRand(): void
     {
         \Colopl\ColoplBc\Php70\srand(5678);
-        if (\PHP_ZTS === 0) {
+        if ((bool) \PHP_ZTS === false) {
             self::assertSame(\Colopl\ColoplBc\Php70\rand(), 1860157456);
         } else {
             self::assertSame(\Colopl\ColoplBc\Php70\rand(), 1173971923);
@@ -71,7 +71,7 @@ public function testShuffle(): void
         \Colopl\ColoplBc\Php70\srand(1234);
         \Colopl\ColoplBc\Php70\shuffle($arr);
 
-        if (\PHP_ZTS === 0) {
+        if ((bool) \PHP_ZTS === false) {
             self::assertSame($arr, [2, 3, 4, 1]);
         } else {
             self::assertSame($arr, [4, 2, 1, 3]);
@@ -83,7 +83,7 @@ public function testStrShuffle(): void
         $str = 'Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.';
         \Colopl\ColoplBc\Php70\srand(1234);
 
-        if (\PHP_ZTS === 0) {
+        if ((bool) \PHP_ZTS === false) {
             self::assertSame(
                 \Colopl\ColoplBc\Php70\str_shuffle($str),
                 'cfapiqi uogi txnrdaeqvnataten ume v aiisalm  isiatdaduaeudr eenteotscdm itdenrieuaicii loi aaot imxll ne luecat uri ipp a l moplaur tsarc.eptuisrccdlotep ecorU oeaceqsuerno .t li sa  rerldulidieoor i n nd  tloiii eeulds  ithsnot btrnf ilm a,nuto umdscd viee.amndrueonmce ns dancratmamo inuios ilmo sg a neo ci. eispiisu pueoe umurt denaamlmiu ,loi ptctaurst lrinm usLrdto  gru coaetucnuliittro, npemeDnpt s,efdlq q teoiabuEet ert ioinu tlbxoo o '
@@ -100,7 +100,7 @@ public function testArrayRand(): void
     {
         \Colopl\ColoplBc\Php70\srand(1234);
 
-        if (\PHP_ZTS === 0) {
+        if ((bool) \PHP_ZTS === false) {
             self::assertSame(
                 \Colopl\ColoplBc\Php70\array_rand([1, 2, 3, 4, 5], 3),
                 [0, 1, 3]