1 files changed, 41 insertions, 0 deletions
diff --git a/packages/cli/src/ui/utils/textUtils.test.ts b/packages/cli/src/ui/utils/textUtils.test.ts
new file mode 100644
index 00000000..5dd08875
--- /dev/null
+++ b/packages/cli/src/ui/utils/textUtils.test.ts
@@ -0,0 +1,41 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { isBinary } from './textUtils';
+
+describe('textUtils', () => {
+  describe('isBinary', () => {
+    it('should return true for a buffer containing a null byte', () => {
+      const buffer = Buffer.from([
+        0x89, 0x50, 0x4e, 0x47, 0x0d, 0x1a, 0x0a, 0x00,
+      ]);
+      expect(isBinary(buffer)).toBe(true);
+    });
+
+    it('should return false for a buffer containing only text', () => {
+      const buffer = Buffer.from('This is a test string.');
+      expect(isBinary(buffer)).toBe(false);
+    });
+
+    it('should return false for an empty buffer', () => {
+      const buffer = Buffer.from([]);
+      expect(isBinary(buffer)).toBe(false);
+    });
+
+    it('should return false for a null or undefined buffer', () => {
+      expect(isBinary(null)).toBe(false);
+      expect(isBinary(undefined)).toBe(false);
+    });
+
+    it('should only check the sample size', () => {
+      const longBufferWithNullByteAtEnd = Buffer.concat([
+        Buffer.from('a'.repeat(1024)),
+        Buffer.from([0x00]),
+      ]);
+      expect(isBinary(longBufferWithNullByteAtEnd, 512)).toBe(false);
+    });
+  });
+});