1 files changed, 114 insertions, 0 deletions
diff --git a/tests/unit/truncate_test.ts b/tests/unit/truncate_test.ts
new file mode 100644
index 000000000..95b76052d
--- /dev/null
+++ b/tests/unit/truncate_test.ts
@@ -0,0 +1,114 @@
+// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
+import { assertEquals, assertRejects, assertThrows } from "./test_util.ts";
+
+Deno.test(
+  { permissions: { read: true, write: true } },
+  function ftruncateSyncSuccess() {
+    const filename = Deno.makeTempDirSync() + "/test_ftruncateSync.txt";
+    using file = Deno.openSync(filename, {
+      create: true,
+      read: true,
+      write: true,
+    });
+
+    file.truncateSync(20);
+    assertEquals(Deno.readFileSync(filename).byteLength, 20);
+    file.truncateSync(5);
+    assertEquals(Deno.readFileSync(filename).byteLength, 5);
+    file.truncateSync(-5);
+    assertEquals(Deno.readFileSync(filename).byteLength, 0);
+
+    Deno.removeSync(filename);
+  },
+);
+
+Deno.test(
+  { permissions: { read: true, write: true } },
+  async function ftruncateSuccess() {
+    const filename = Deno.makeTempDirSync() + "/test_ftruncate.txt";
+    using file = await Deno.open(filename, {
+      create: true,
+      read: true,
+      write: true,
+    });
+
+    await file.truncate(20);
+    assertEquals((await Deno.readFile(filename)).byteLength, 20);
+    await file.truncate(5);
+    assertEquals((await Deno.readFile(filename)).byteLength, 5);
+    await file.truncate(-5);
+    assertEquals((await Deno.readFile(filename)).byteLength, 0);
+
+    await Deno.remove(filename);
+  },
+);
+
+Deno.test(
+  { permissions: { read: true, write: true } },
+  function truncateSyncSuccess() {
+    const filename = Deno.makeTempDirSync() + "/test_truncateSync.txt";
+    Deno.writeFileSync(filename, new Uint8Array(5));
+    Deno.truncateSync(filename, 20);
+    assertEquals(Deno.readFileSync(filename).byteLength, 20);
+    Deno.truncateSync(filename, 5);
+    assertEquals(Deno.readFileSync(filename).byteLength, 5);
+    Deno.truncateSync(filename, -5);
+    assertEquals(Deno.readFileSync(filename).byteLength, 0);
+    Deno.removeSync(filename);
+  },
+);
+
+Deno.test(
+  { permissions: { read: true, write: true } },
+  async function truncateSuccess() {
+    const filename = Deno.makeTempDirSync() + "/test_truncate.txt";
+    await Deno.writeFile(filename, new Uint8Array(5));
+    await Deno.truncate(filename, 20);
+    assertEquals((await Deno.readFile(filename)).byteLength, 20);
+    await Deno.truncate(filename, 5);
+    assertEquals((await Deno.readFile(filename)).byteLength, 5);
+    await Deno.truncate(filename, -5);
+    assertEquals((await Deno.readFile(filename)).byteLength, 0);
+    await Deno.remove(filename);
+  },
+);
+
+Deno.test({ permissions: { write: false } }, function truncateSyncPerm() {
+  assertThrows(() => {
+    Deno.truncateSync("/test_truncateSyncPermission.txt");
+  }, Deno.errors.PermissionDenied);
+});
+
+Deno.test({ permissions: { write: false } }, async function truncatePerm() {
+  await assertRejects(async () => {
+    await Deno.truncate("/test_truncatePermission.txt");
+  }, Deno.errors.PermissionDenied);
+});
+
+Deno.test(
+  { permissions: { read: true, write: true } },
+  function truncateSyncNotFound() {
+    const filename = "/badfile.txt";
+    assertThrows(
+      () => {
+        Deno.truncateSync(filename);
+      },
+      Deno.errors.NotFound,
+      `truncate '${filename}'`,
+    );
+  },
+);
+
+Deno.test(
+  { permissions: { read: true, write: true } },
+  async function truncateSyncNotFound() {
+    const filename = "/badfile.txt";
+    await assertRejects(
+      async () => {
+        await Deno.truncate(filename);
+      },
+      Deno.errors.NotFound,
+      `truncate '${filename}'`,
+    );
+  },
+);