diff --git a/core/modules/system/system.install b/core/modules/system/system.install
index c6851ef..05fa4fc 100644
--- a/core/modules/system/system.install
+++ b/core/modules/system/system.install
@@ -186,7 +186,6 @@ function system_requirements($phase) {
     ];
   }
 
-  $is_test_site = drupal_valid_test_ua() || getenv('DRUPAL_DEV_SITE_PATH');
   if (version_compare($phpversion, DRUPAL_MINIMUM_UPDATE_PHP) < 0) {
     $requirements['php']['description'] = t('Your PHP installation is too old. Drupal requires at least PHP %version.', ['%version' => DRUPAL_MINIMUM_UPDATE_PHP]);
     $requirements['php']['severity'] = REQUIREMENT_ERROR;
@@ -201,7 +200,7 @@ function system_requirements($phase) {
       $requirements['php']['severity'] = REQUIREMENT_WARNING;
     }
     // Allow test installations of Drupal on older PHP versions.
-    elseif (!$is_test_site) {
+    elseif (!drupal_valid_test_ua()) {
       $requirements['php']['description'] = t('Your PHP installation is too old. Drupal requires at least PHP %version.', ['%version' => DRUPAL_MINIMUM_PHP]);
       $requirements['php']['severity'] = REQUIREMENT_ERROR;
       // If PHP is old, it's not safe to continue with the requirements check.
diff --git a/core/tests/Drupal/Tests/Core/Command/QuickStartTest.php b/core/tests/Drupal/Tests/Core/Command/QuickStartTest.php
index 5622aa2..9333bba 100644
--- a/core/tests/Drupal/Tests/Core/Command/QuickStartTest.php
+++ b/core/tests/Drupal/Tests/Core/Command/QuickStartTest.php
@@ -83,6 +83,10 @@ public function tearDown() {
    * Tests the quick-start command.
    */
   public function testQuickStartCommand() {
+    if (version_compare(phpversion(), DRUPAL_MINIMUM_PHP) < 0) {
+      $this->markTestSkipped();
+    }
+
     // Install a site using the standard profile to ensure the one time login
     // link generation works.
 
@@ -133,9 +137,47 @@ public function testQuickStartCommand() {
   }
 
   /**
+   * Tests that the installer throws a requirement error on older PHP versions.
+   */
+  public function testPhpRequirement() {
+    if (version_compare(phpversion(), DRUPAL_MINIMUM_PHP) >= 0) {
+      $this->markTestSkipped();
+    }
+
+    $install_command = [
+      $this->php,
+      'core/scripts/drupal',
+      'quick-start',
+      'standard',
+      "--site-name='Test site {$this->testDb->getDatabasePrefix()}'",
+      '--suppress-login',
+    ];
+    $process = new Process($install_command, NULL, ['DRUPAL_DEV_SITE_PATH' => $this->testDb->getTestSitePath()]);
+    $process->inheritEnvironmentVariables();
+    $process->setTimeout(500);
+    $process->start();
+    while ($process->isRunning()) {
+      // Wait for more output.
+      sleep(1);
+    }
+
+    $error_output = $process->getErrorOutput();
+    $this->assertContains('Your PHP installation is too old.', $error_output);
+    $this->assertContains('Drupal requires at least PHP', $error_output);
+    $this->assertContains(DRUPAL_MINIMUM_PHP, $error_output);
+
+    // Stop the web server.
+    $process->stop();
+  }
+
+  /**
    * Tests the quick-start commands.
    */
   public function testQuickStartInstallAndServerCommands() {
+    if (version_compare(phpversion(), DRUPAL_MINIMUM_PHP) < 0) {
+      $this->markTestSkipped();
+    }
+
     // Install a site.
     $install_command = [
       $this->php,
@@ -290,3 +332,7 @@ protected function fileUnmanagedDeleteRecursive($path, $callback = NULL) {
   }
 
 }
+
+if (!defined('DRUPAL_MINIMUM_PHP')) {
+  define('DRUPAL_MINIMUM_PHP', '7.0.0');
+}