diff --git a/.gitignore b/.gitignore
index 47f36f6..31df0e3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 .DS_Store
-vendor
\ No newline at end of file
+vendor
+tests/tmp/*
\ No newline at end of file
diff --git a/src/Storage/FilesystemJsonStorage.php b/src/Storage/FilesystemJsonStorage.php
index ddff741..be10d8e 100644
--- a/src/Storage/FilesystemJsonStorage.php
+++ b/src/Storage/FilesystemJsonStorage.php
@@ -50,7 +50,7 @@ class FilesystemJsonStorage implements TokenStorageInterface {
 
 	public function put(string $key, array $data): bool {
 		// Ensure that the containing folder exists.
-		mkdir($this->path, 0777, true);
+		@mkdir($this->path, 0777, true);
 
 		return file_put_contents($this->getPath($key), json_encode($data)) !== false;
 	}
diff --git a/tests/FilesystemJsonStorageTest.php b/tests/FilesystemJsonStorageTest.php
new file mode 100644
index 0000000..c5b6c18
--- /dev/null
+++ b/tests/FilesystemJsonStorageTest.php
@@ -0,0 +1,56 @@
+<?php declare(strict_types=1);
+
+namespace Taproot\IndieAuth\Test;
+
+use DirectoryIterator;
+use PHPUnit\Framework\TestCase;
+use Taproot\IndieAuth\Storage\FilesystemJsonStorage;
+
+const TMP_DIR = __DIR__ . '/tmp';
+
+class FilesystemJsonStorageTest extends TestCase {
+	protected function setUp(): void {
+		// Clean tmp dir.
+		foreach (new DirectoryIterator(TMP_DIR) as $fileInfo) {
+			if ($fileInfo->isFile()) {
+				unlink($fileInfo->getPathname());
+			}
+		}
+	}
+
+	protected function tearDown(): void {
+		// Clean tmp dir.
+		foreach (new DirectoryIterator(TMP_DIR) as $fileInfo) {
+			if ($fileInfo->isFile()) {
+				unlink($fileInfo->getPathname());
+			}
+		}
+	}
+	
+	public function testCrud() {
+		$s = new FilesystemJsonStorage(TMP_DIR, 0, false);
+
+		$t1data = ['example' => 'data'];
+		$t1path = TMP_DIR . '/t1.json';
+
+		$this->assertTrue($s->put('t1', $t1data), "Saving t1 data failed");
+
+		$this->assertFileExists($t1path, "t1 was not stored to $t1path");
+		
+		$this->assertEquals($t1data, $s->get('t1'), "The result of getting t1 did not match the saved data.");
+
+		$s->delete('t1');
+
+		$this->assertFileDoesNotExist($t1path, "t1 was not successfully deleted.");
+
+		$this->assertNull($s->get('t1'), "Getting a nonexistent key did not return null");
+	}
+
+	public function testCleanUp() {
+		$s = new FilesystemJsonStorage(TMP_DIR, 1, false);
+		$s->put('t1', ['example' => 'data']);
+		sleep(2);
+		$s->cleanUp();
+		$this->assertNull($s->get('t1'), 't1 was not cleaned up after expiring.');
+	}
+}