diff --git a/.gitignore b/.gitignore
index 4a485fb2..dcd18b14 100644
--- a/.gitignore
+++ b/.gitignore
@@ -11,3 +11,4 @@ composer.lock
 phpunit.xml
 phpcs.xml
 .phpcs.xml
+.phpunit.result.cache
diff --git a/composer.json b/composer.json
index 90f8a12e..05b17a43 100644
--- a/composer.json
+++ b/composer.json
@@ -20,7 +20,7 @@
         "wp-cli/eval-command": "^1 || ^2",
         "wp-cli/wp-cli": "^2.5.1",
         "wp-coding-standards/wpcs": "^3",
-        "yoast/phpunit-polyfills": "^1.0.3"
+        "yoast/phpunit-polyfills": "^1.0.3 || ^2.0.1"
     },
     "require-dev": {
         "roave/security-advisories": "dev-latest"
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index 6d71ef1b..4ec777f6 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -4,8 +4,8 @@
 	>
 	<testsuites>
 		<testsuite name="default">
-			<directory prefix="spec-" suffix=".php">tests/</directory>
-			<directory prefix="test-" suffix=".php">tests/</directory>
+			<directory prefix="Spec" suffix=".php">tests/</directory>
+			<directory prefix="Test" suffix=".php">tests/tests</directory>
 		</testsuite>
 	</testsuites>
 </phpunit>
diff --git a/tests/bootstrap.php b/tests/bootstrap.php
index 73b76032..0b7f434e 100644
--- a/tests/bootstrap.php
+++ b/tests/bootstrap.php
@@ -29,7 +29,7 @@
 
 require_once VENDOR_DIR . '/autoload.php';
 require_once WP_CLI_ROOT . '/php/utils.php';
-require_once __DIR__ . '/wp-cli-testcase.php';
+require_once __DIR__ . '/includes/TestCase.php';
 
 function wpcli_tests_include_config( array $config_filenames = [] ) {
 	$config_filename = false;
diff --git a/tests/wp-cli-testcase.php b/tests/includes/TestCase.php
similarity index 100%
rename from tests/wp-cli-testcase.php
rename to tests/includes/TestCase.php
diff --git a/tests/test-behat-tags.php b/tests/tests/TestBehatTags.php
similarity index 95%
rename from tests/test-behat-tags.php
rename to tests/tests/TestBehatTags.php
index 17d959a4..d819a181 100644
--- a/tests/test-behat-tags.php
+++ b/tests/tests/TestBehatTags.php
@@ -3,7 +3,7 @@
 use WP_CLI\Tests\TestCase;
 use WP_CLI\Utils;
 
-class BehatTagsTest extends TestCase {
+class TestBehatTags extends TestCase {
 
 	public $temp_dir;
 
@@ -39,7 +39,7 @@ public function test_behat_tags_wp_version_github_token( $env, $expected ) {
 		putenv( 'WP_VERSION' );
 		putenv( 'GITHUB_TOKEN' );
 
-		$behat_tags = dirname( __DIR__ ) . '/utils/behat-tags.php';
+		$behat_tags = dirname( dirname( __DIR__ ) ) . '/utils/behat-tags.php';
 
 		$contents = '@require-wp-4.6 @require-wp-4.8 @require-wp-4.9 @less-than-wp-4.6 @less-than-wp-4.8 @less-than-wp-4.9';
 		file_put_contents( $this->temp_dir . '/features/wp_version.feature', $contents );
@@ -64,7 +64,7 @@ public function test_behat_tags_wp_version_github_token( $env, $expected ) {
 		putenv( false === $env_github_token ? 'GITHUB_TOKEN' : "GITHUB_TOKEN=$env_github_token" );
 	}
 
-	public function data_behat_tags_wp_version_github_token() {
+	public static function data_behat_tags_wp_version_github_token() {
 		return array(
 			array( 'WP_VERSION=4.5', '~@require-wp-4.6&&~@require-wp-4.8&&~@require-wp-4.9&&~@github-api' ),
 			array( 'WP_VERSION=4.6', '~@require-wp-4.8&&~@require-wp-4.9&&~@less-than-wp-4.6&&~@github-api' ),
@@ -85,7 +85,7 @@ public function test_behat_tags_php_version() {
 
 		putenv( 'GITHUB_TOKEN' );
 
-		$behat_tags = dirname( __DIR__ ) . '/utils/behat-tags.php';
+		$behat_tags = dirname( dirname( __DIR__ ) ) . '/utils/behat-tags.php';
 
 		$php_version = substr( PHP_VERSION, 0, 3 );
 		$contents    = '';
@@ -142,7 +142,7 @@ public function test_behat_tags_extension() {
 
 		putenv( 'GITHUB_TOKEN' );
 
-		$behat_tags = dirname( __DIR__ ) . '/utils/behat-tags.php';
+		$behat_tags = dirname( dirname( __DIR__ ) ) . '/utils/behat-tags.php';
 
 		file_put_contents( $this->temp_dir . '/features/extension.feature', '@require-extension-imagick @require-extension-curl' );