diff --git a/Process.php b/Process.php
index 1aaf730d..435efb3c 100644
--- a/Process.php
+++ b/Process.php
@@ -1202,7 +1202,7 @@ public static function isTtySupported(): bool
     {
         static $isTtySupported;
 
-        return $isTtySupported ??= ('/' === \DIRECTORY_SEPARATOR && stream_isatty(\STDOUT));
+        return $isTtySupported ??= ('/' === \DIRECTORY_SEPARATOR && stream_isatty(\STDOUT) && @is_writable('/dev/tty'));
     }
 
     /**
diff --git a/Tests/ExecutableFinderTest.php b/Tests/ExecutableFinderTest.php
index a0f62273..a1b8d6d5 100644
--- a/Tests/ExecutableFinderTest.php
+++ b/Tests/ExecutableFinderTest.php
@@ -99,12 +99,16 @@ public function testFindWithOpenBaseDir()
         }
 
         putenv('PATH='.\dirname(\PHP_BINARY));
-        $this->iniSet('open_basedir', \dirname(\PHP_BINARY).\PATH_SEPARATOR.'/');
+        $initialOpenBaseDir = ini_set('open_basedir', \dirname(\PHP_BINARY).\PATH_SEPARATOR.'/');
 
-        $finder = new ExecutableFinder();
-        $result = $finder->find($this->getPhpBinaryName());
+        try {
+            $finder = new ExecutableFinder();
+            $result = $finder->find($this->getPhpBinaryName());
 
-        $this->assertSamePath(\PHP_BINARY, $result);
+            $this->assertSamePath(\PHP_BINARY, $result);
+        } finally {
+            ini_set('open_basedir', $initialOpenBaseDir);
+        }
     }
 
     public function testFindBatchExecutableOnWindows()