1 files changed, 99 insertions, 0 deletions
diff --git a/cli/tests/unit_node/_fs/_fs_truncate_test.ts b/cli/tests/unit_node/_fs/_fs_truncate_test.ts
new file mode 100644
index 000000000..3aff3fac2
--- /dev/null
+++ b/cli/tests/unit_node/_fs/_fs_truncate_test.ts
@@ -0,0 +1,99 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+import {
+  assertEquals,
+  assertThrows,
+  fail,
+} from "../../../../test_util/std/testing/asserts.ts";
+import { truncate, truncateSync } from "node:fs";
+
+Deno.test({
+  name: "ASYNC: no callback function results in Error",
+  fn() {
+    assertThrows(
+      () => {
+        // @ts-expect-error Argument of type 'number' is not assignable to parameter of type 'NoParamCallback'
+        truncate("some/path", 0);
+      },
+      Error,
+      "No callback function supplied",
+    );
+  },
+});
+
+Deno.test({
+  name: "ASYNC: truncate entire file contents",
+  async fn() {
+    const file: string = Deno.makeTempFileSync();
+    await Deno.writeFile(file, new TextEncoder().encode("hello world"));
+
+    await new Promise<void>((resolve, reject) => {
+      truncate(file, (err: Error | null) => {
+        if (err !== null) reject();
+        else resolve();
+      });
+    })
+      .then(
+        () => {
+          const fileInfo: Deno.FileInfo = Deno.lstatSync(file);
+          assertEquals(fileInfo.size, 0);
+        },
+        () => {
+          fail("No error expected");
+        },
+      )
+      .finally(() => Deno.removeSync(file));
+  },
+});
+
+Deno.test({
+  name: "ASYNC: truncate file to a size of precisely len bytes",
+  async fn() {
+    const file: string = Deno.makeTempFileSync();
+    await Deno.writeFile(file, new TextEncoder().encode("hello world"));
+
+    await new Promise<void>((resolve, reject) => {
+      truncate(file, 3, (err: Error | null) => {
+        if (err !== null) reject();
+        else resolve();
+      });
+    })
+      .then(
+        () => {
+          const fileInfo: Deno.FileInfo = Deno.lstatSync(file);
+          assertEquals(fileInfo.size, 3);
+        },
+        () => {
+          fail("No error expected");
+        },
+      )
+      .finally(() => Deno.removeSync(file));
+  },
+});
+
+Deno.test({
+  name: "SYNC: truncate entire file contents",
+  fn() {
+    const file: string = Deno.makeTempFileSync();
+    try {
+      truncateSync(file);
+      const fileInfo: Deno.FileInfo = Deno.lstatSync(file);
+      assertEquals(fileInfo.size, 0);
+    } finally {
+      Deno.removeSync(file);
+    }
+  },
+});
+
+Deno.test({
+  name: "SYNC: truncate file to a size of precisely len bytes",
+  fn() {
+    const file: string = Deno.makeTempFileSync();
+    try {
+      truncateSync(file, 3);
+      const fileInfo: Deno.FileInfo = Deno.lstatSync(file);
+      assertEquals(fileInfo.size, 3);
+    } finally {
+      Deno.removeSync(file);
+    }
+  },
+});